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Encyclopedia > Solar system
Planets and dwarf planets of the Solar System; while the sizes are to scale, the relative distances from the Sun are not.
Planets and dwarf planets of the Solar System; while the sizes are to scale, the relative distances from the Sun are not.

The Solar System or solar system[a] consists of the Sun and the other celestial objects gravitationally bound to it: the eight planets, their 166 known moons,[1] three dwarf planets (Ceres, Pluto, and Eris and their four known moons), and billions of small bodies. This last category includes asteroids, Kuiper belt objects, comets, meteoroids, and interplanetary dust. An artists concept of a protoplanetary disc. ... A star system or stellar system is a small number of stars that orbit each other,[1] bound by gravitational attraction. ... An extrasolar planet, or exoplanet, is a planet beyond the Solar System. ... Image File history File links Download high-resolution version (1280x720, 54 KB)The solar system is the largest known in the galaxy. ... Image File history File links Download high-resolution version (1280x720, 54 KB)The solar system is the largest known in the galaxy. ... Sol redirects here. ... Astronomical objects are significant physical entities, associations or structures which current science has confirmed to exist in space. ... Gravity redirects here. ... This article is about the astronomical term. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Artists impression of Pluto (background) and Charon (foreground). ... Spectral type: G[8] Absolute magnitude: 3. ... For other uses, see Pluto (disambiguation). ... Absolute magnitude: −1. ... A Small Solar System Body (SSSB) is a term defined in 2006 by the International Astronomical Union to describe objects in the Solar System that are neither planets nor dwarf planets: [1] This encompasses: all minor planets apart from the dwarf planets, : the classical asteroids, (except for 1 Ceres, the... For other uses, see Asteroid (disambiguation). ... The Kuiper belt, derived from data from the Minor Planet Center. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... “Meteor” redirects here. ... Interplanetary dust cloud The interplanetary dust cloud has been studied for many years in order to understand its nature, origin, and relationship to solar systems (our own, as well as extrasolar systems). ...


In broad terms, the charted regions of the Solar System consist of the Sun, four terrestrial inner planets, an asteroid belt composed of small rocky bodies, four gas giant outer planets, and a second belt, the Kuiper belt, composed of icy objects. Beyond the Kuiper belt is the scattered disc, the heliopause, and ultimately the hypothetical Oort cloud. The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... For other uses, see Asteroid (disambiguation). ... This article does not cite any references or sources. ... The Kuiper belt, derived from data from the Minor Planet Center. ... Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ... The heliosphere is a bubble in space produced by the solar wind. ... Artists rendering of the Oort cloud and the Kuiper Belt. ...


In order of their distances from the Sun, the terrestrial planets are:

The outer gas giants (or jovians) are: This article is about the planet. ... For other uses, see Venus (disambiguation). ... This article is about Earth as a planet. ... Adjectives: Martian Atmosphere Surface pressure: 0. ...

The three dwarf planets are For other uses, see Jupiter (disambiguation). ... This article is about the planet. ... For other uses, see Uranus (disambiguation). ... For other uses, see Neptune (disambiguation). ...

  • Ceres, the largest object in the asteroid belt;
  • Pluto, the largest known Kuiper belt object; and
  • Eris, the largest of the three which lies in the scattered disc.

Six of the eight planets and two of the dwarf planets are in turn orbited by natural satellites, usually termed "moons" after Earth's Moon, and each of the outer planets is encircled by planetary rings of dust and other particles. All the planets except Earth are named after deities from Greco-Roman mythology. Spectral type: G[8] Absolute magnitude: 3. ... For other uses, see Pluto (disambiguation). ... Absolute magnitude: −1. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... This article is about Earths moon. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... The bust of Zeus found at Otricoli (Sala Rotonda, Museo Pio-Clementino, Vatican) Greek mythology is the body of stories belonging to the Ancient Greeks concerning their gods and heroes, the nature of the world and the origins and significance of their own cult and ritual practices. ... A head of Minerva found in the ruins of the Roman baths in Bath Roman mythology, the mythological beliefs of the people of Ancient Rome, can be considered as having two parts. ... For other uses, see Mythology (disambiguation). ...

Contents

Terminology

The zones of the Solar system: the inner solar system, the asteroid belt, the giant planets (jovians) and the Kuiper Belt. Orbits not to scale.
The zones of the Solar system: the inner solar system, the asteroid belt, the giant planets (jovians) and the Kuiper Belt. Orbits not to scale.
See also: Definition of planet

Objects orbiting the Sun are divided into three classes: planets, dwarf planets, and small Solar System bodies. Photograph of the planet Neptune and its moon Triton, taken by Voyager 2 as it entered the outer solar system. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ...


A planet is any body in orbit around the Sun that a) has enough mass to form itself into a spherical shape and b) has cleared its immediate neighbourhood of all smaller objects. By this definition, the Solar System has eight known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. From the time of its discovery in 1930 until 2006, Pluto was considered the Solar System's ninth planet. But in the late 20th and early 21st centuries, many objects similar to Pluto were discovered in the outer Solar System, most notably Eris, which is slightly larger than Pluto. On August 24, 2006, the International Astronomical Union defined the term "planet" for the first time, excluding Pluto and reclassifying it under the new category of dwarf planet along with Eris and Ceres.[2] A dwarf planet is not required to clear its neighbourhood of other celestial bodies. Other objects that may become classified as dwarf planets are Sedna, Orcus, and Quaoar. This article is about the astronomical term. ... For other uses, see Mass (disambiguation). ... For other uses, see Sphere (disambiguation). ... This article or section may be confusing or unclear for some readers, and should be edited to rectify this. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... IAU redirects here. ... The final definition left the solar system with eight planets. ... Artists impression of Pluto (background) and Charon (foreground). ... Absolute magnitude: −1. ... Spectral type: G[8] Absolute magnitude: 3. ... you are abunch of bull | bgcolour=#FFFFC0 | name=90377 Sedna | image= | caption= Sedna is located in the center of the green circle | discovery=yes | discoverer=M. Brown, C. Trujillo, D. Rabinowitz | discovered=November 14, 2003 | mp_name=90377 Sedna | alt_names= | mp_category=Trans-Neptunian object | epoch=September 26, 1990 (JD 2448160. ... 90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. ... 50000 Quaoar (pronounced kwaa·waar or kwow·ər, English IPA: , Tongva ) [2] is a Trans-Neptunian object orbiting the Sun in the Kuiper belt. ...


The remainder of the objects in orbit around the Sun are small Solar System bodies (SSSBs).[3] A Small Solar System Body (SSSB) is a term defined in 2006 by the International Astronomical Union to describe objects in the Solar System that are neither planets nor dwarf planets: [1] This encompasses: all minor planets apart from the dwarf planets, : the classical asteroids, (except for 1 Ceres, the...


Natural satellites, or moons, are those objects in orbit around planets, dwarf planets and SSSBs, rather than the Sun itself. A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ...


Astronomers usually measure distances within the Solar System in astronomical units (AU). One AU is the approximate distance between the Earth and the Sun, or roughly 149,598,000 km (93,000,000 mi). Pluto is roughly 38 AU from the Sun while Jupiter lies at roughly 5.2 AU. One light-year, the best known unit of interstellar distance, is roughly 63,240 AU. A body's distance from the Sun varies in the course of its year. Its closest approach to the Sun is called its perihelion, while its farthest distance from the Sun is called its aphelion. The astronomical unit (AU or au or a. ... “km” redirects here. ... “Miles” redirects here. ... A light-year, symbol ly, is the distance light travels in one year: exactly 9. ... A year (from Old English gÄ“r) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ...


Informally, the Solar System is sometimes divided into separate zones. The inner Solar System includes the four terrestrial planets and the main asteroid belt. Some define the outer Solar System as comprising everything beyond the asteroids.[4] Others define it as the region beyond Neptune, with the four gas giants considered a separate "middle zone".[5] The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... This article does not cite any references or sources. ...


Layout and structure

The ecliptic viewed in sunlight from behind the Moon in this Clementine image. From left to right: Mercury, Mars, Saturn.
The ecliptic viewed in sunlight from behind the Moon in this Clementine image. From left to right: Mercury, Mars, Saturn.

The principal component of the Solar System is the Sun, a main sequence G2 star that contains 99.86% of the system's known mass and dominates it gravitationally.[6] Jupiter and Saturn, the Sun's two largest orbiting bodies, account for more than 90% of the system's remaining mass.[b] Image File history File linksMetadata Solarsystem. ... Image File history File linksMetadata Solarsystem. ... Clementine was a joint space project between the Ballistic Missile Defense Organization (BMDO, previously the Strategic Defense Initiative Organization, or SDIO) and NASA. The objective of the mission was to test sensors and spacecraft components under extended exposure to the space environment and to make scientific observations of the Moon... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... This article is about the astronomical object. ... For other uses, see Mass (disambiguation). ... Gravity redirects here. ...


Most large objects in orbit around the Sun lie near the plane of Earth's orbit, known as the ecliptic. The planets are very close to the ecliptic while comets and Kuiper belt objects are usually at significantly greater angles to it. The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... The Kuiper belt, derived from data from the Minor Planet Center. ...

The orbits of the bodies in the Solar System to scale (clockwise from top left)
The orbits of the bodies in the Solar System to scale (clockwise from top left)

All of the planets and most other objects also orbit with the Sun's rotation in a counter-clockwise direction as viewed from a point above the Sun's north pole. There are exceptions, such as Halley's Comet. This NASA diagram demonstrates the presumed distance of the Oort cloud compared to the solar systems planets, the Kuiper belt, and the 90377 Sedna planetoid. ... This NASA diagram demonstrates the presumed distance of the Oort cloud compared to the solar systems planets, the Kuiper belt, and the 90377 Sedna planetoid. ... This article is about the comet. ...


Objects travel around the Sun following Kepler's laws of planetary motion. Each object orbits along an approximate ellipse with the Sun at one focus of the ellipse. The closer an object is to the Sun, the faster it moves. The orbits of the planets are nearly circular, but many comets, asteroids and objects of the Kuiper belt follow highly-elliptical orbits. Johannes Keplers primary contributions to astronomy/astrophysics were his three laws of planetary motion. ...


To cope with the vast distances involved, many representations of the Solar System show orbits the same distance apart. In reality, with a few exceptions, the farther a planet or belt is from the Sun, the larger the distance between it and the previous orbit. For example, Venus is approximately 0.33 AU farther out than Mercury, while Saturn is 4.3 AU out from Jupiter, and Neptune lies 10.5 AU out from Uranus. Attempts have been made to determine a correlation between these orbital distances (see Titius-Bode law), but no such theory has been accepted. The Titius-Bode law (or Bodes law) is the observation that orbits of planets in the solar system closely follow a simple geometric rule. ...

Formation and evolution

Artist's conception of a protoplanetary disk
Artist's conception of a protoplanetary disk

The Solar System is believed to have formed according to the nebular hypothesis, which holds that it emerged from the gravitational collapse of a giant molecular cloud 4.6 billion years ago. This initial cloud was likely several light-years across and probably birthed several stars.[7] Studies of ancient meteorites reveal traces of elements only formed in the hearts of very large exploding stars, indicating that the Sun formed within a star cluster, and in range of a number of nearby supernovae explosions. The shock wave from these supernovae may have triggered the formation of the Sun by creating regions of overdensity in the surrounding nebula, allowing gravitational forces to overcome internal gas pressures and cause collapse.[8] The theories concerning the formation and evolution of the Solar System are complex and varied, interweaving various scientific disciplines, from astronomy and physics to geology and planetary science. ... Image File history File links Artists concept of a protoplanetary disk. ... Image File history File links Artists concept of a protoplanetary disk. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... A planetary disk forming in the Orion Nebula In this artists conception, of a planet spins through a clearing in a nearby stars dusty, planet-forming disc In cosmogony, the nebular hypothesis is the currently accepted argument about how Earths Solar System formed. ... A molecular cloud is a type of interstellar cloud whose density and size permits the formation of molecules, most commonly molecular hydrogen (H2). ... Willamette Meteorite A meteorite is a natural object originating in outer space that survives an impact with the Earths surface without being destroyed. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... This article or section does not cite its references or sources. ... For other uses, see Supernova (disambiguation). ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... Gas phase particles (atoms, molecules, or ions) move around freely Gas is one of the four major states of matter, consisting of freely moving atoms or molecules without a definite shape and without a definite volume. ...


The region that would become the Solar System, known as the pre-solar nebula,[9] had a diameter of between 7000 and 20,000 AU[7][10] and a mass just over that of the Sun (by between 0.1 and 0.001 solar masses).[11] As the nebula collapsed, conservation of angular momentum made it rotate faster. As the material within the nebula condensed, the atoms within it began to collide with increasing frequency. The centre, where most of the mass collected, became increasingly hotter than the surrounding disc.[7] As gravity, gas pressure, magnetic fields, and rotation acted on the contracting nebula, it began to flatten into a spinning protoplanetary disc with a diameter of roughly 200 AU[7] and a hot, dense protostar at the centre.[12][13] This article or section does not cite any references or sources. ... This gyroscope remains upright while spinning due to its angular momentum. ... For other uses, see Condensation (disambiguation). ... Properties For other meanings of Atom, see Atom (disambiguation). ... For the indie-pop band, see The Magnetic Fields. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... A Protostar is an object that forms by contraction out of the gas of a giant molecular cloud in the interstellar medium. ...


Studies of T Tauri stars, young, pre-fusing solar mass stars believed to be similar to the Sun at this point in its evolution, show that they are often accompanied by discs of pre-planetary matter.[11] These discs extend to several hundred AU and reach only a thousand kelvins at their hottest.[14] Drawing of a T-Tauri star with a circumstellar accretion disk T Tauri stars are a class of variable stars named after their prototype - T Tauri. ... For other uses, see Kelvin (disambiguation). ...

Hubble image of protoplanetary disks in the Orion Nebula, a light-years-wide "stellar nursery" likely very similar to the primordial nebula from which our Sun formed.
Hubble image of protoplanetary disks in the Orion Nebula, a light-years-wide "stellar nursery" likely very similar to the primordial nebula from which our Sun formed.

After 100 million years, the pressure and density of hydrogen in the centre of the collapsing nebula became great enough for the protosun to begin thermonuclear fusion. This increased until hydrostatic equilibrium was achieved, with the thermal energy countering the force of gravitational contraction. At this point the Sun became a full-fledged star.[15] Image File history File links M42proplyds. ... Image File history File links M42proplyds. ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ... The Orion Nebula (also known as Messier 42, M42, or NGC 1976) is a diffuse nebula situated south of Orions Belt. ... This article is about the chemistry of hydrogen. ... A Protostar is an object that forms by contraction out of the gas of a giant molecular cloud in the interstellar medium. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Hydrostatic equilibrium occurs when compression due to gravity is balanced by a pressure gradient which creates a pressure gradient force in the opposite direction. ...


From the remaining cloud of gas and dust (the "solar nebula"), the various planets formed. They are believed to have formed by accretion: the planets began as dust grains in orbit around the central protostar; then gathered by direct contact into clumps between one and ten metres in diameter; then collided to form larger bodies (planetesimals) of roughly 5 km in size; then gradually increased by further collisions at roughly 15 cm per year over the course of the next few million years.[16] This article or section does not cite any references or sources. ... In astrophysics, the term accretion is used for at least two distinct processes. ... Planetesimals are solid objects thought to exist in protoplanetary disks and in debris disks. ... A centimetre (American spelling centimeter, symbol cm) is a unit of length that is equal to one hundredth of a metre, the current SI base unit of length. ...


The inner Solar System was too warm for volatile molecules like water and methane to condense, and so the planetesimals which formed there were relatively small (comprising only 0.6% the mass of the disc)[7] and composed largely of compounds with high melting points, such as silicates and metals. These rocky bodies eventually became the terrestrial planets. Farther out, the gravitational effects of Jupiter made it impossible for the protoplanetary objects present to come together, leaving behind the asteroid belt.[17] 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Methane is a chemical compound with the molecular formula . ... Look up chemical compound in Wiktionary, the free dictionary. ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. ... This article is about metallic materials. ... The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... For other uses, see Asteroid (disambiguation). ...


Farther out still, beyond the frost line, where more volatile icy compounds could remain solid, Jupiter and Saturn became the gas giants. Uranus and Neptune captured much less material and are known as ice giants because their cores are believed to be made mostly of ices (hydrogen compounds).[18][19] In astronomy or planetary physics, the frost line refers to a particular distance in the solar nebula from the central protosun where it is cool enough for hydrogen compounds such as water, ammonia, and methane to condense into solid ice grains. ... This article does not cite any references or sources. ...


Once the young Sun began producing energy, the solar wind (see below) blew the gas and dust in the protoplanetary disk into interstellar space and ended the growth of the planets. T Tauri stars have far stronger stellar winds than more stable, older stars.[20][21] The plasma in the solar wind meeting the heliopause The solar wind is a stream of charged particles (i. ... A solar wind is a stream of particles (mostly high-energy protons ~ 500 keV) which are ejected from the upper atmosphere of a star (in the case of a star other than the Earths Sun, it may be called a stellar wind instead). ...

Artist's conception of the future evolution of our Sun. Left: main sequence; middle: red giant; right: white dwarf

Astronomers estimate that the Solar System as we know it today will last until the Sun begins its journey off of the main sequence. As the Sun burns through its supply of hydrogen fuel, it gets hotter in order to be able to burn the remaining fuel, and so burns it even faster. As a result, the Sun is growing brighter at a rate of roughly ten percent every 1.1 billion years.[22] Image File history File links Redgiantsun. ... Image File history File links Redgiantsun. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ...


Around 6.4 billion years from now, the Sun's core will become hot enough to cause hydrogen fusion to occur in its less dense upper layers. This will cause the Sun to expand to roughly 100 times its current diameter, and become a red giant.[23] At this point, the sun will have cooled and dulled, because of its vastly increased surface area. According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giant stars. ...


Eventually, the Sun's outer layers will fall away, leaving a white dwarf, an extraordinarily dense object, half its original mass but only the size of the Earth.[24] This article or section does not adequately cite its references or sources. ...


Sun

Main article: Sun
The Sun as seen from Earth
The Sun as seen from Earth

The Sun is the Solar System's parent star, and far and away its chief component. Its large mass gives it an interior density high enough to sustain nuclear fusion, which releases enormous amounts of energy, mostly radiated into space as electromagnetic radiation such as visible light. Sol redirects here. ... Image File history File links Download high resolution version (1024x768, 38 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (1024x768, 38 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... For other uses, see Density (disambiguation). ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... Radiant energy is the energy of electromagnetic waves. ... Layers of Atmosphere - not to scale (NOAA)[1] Outer space, sometimes simply called space, refers to the relatively empty regions of the universe outside the atmospheres of celestial bodies. ... This box:      Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. ... Visible light redirects here. ...


The Sun is classified as a moderately large yellow dwarf, but this name is misleading as, compared to stars in our galaxy, the Sun is rather large and bright. Stars are classified by the Hertzsprung-Russell diagram, a graph which plots the brightness of stars against their surface temperatures. Generally, hotter stars are brighter. Stars following this pattern are said to be on the main sequence; the Sun lies right in the middle of it. However, stars brighter and hotter than the Sun are rare, while stars dimmer and cooler are common.[25] Large solar flare recorded by SOHO EIT304 instrument in the ultraviolet. ... For other uses, see Milky Way (disambiguation). ... The Hertzsprung-Russell diagram (usually referred to by the abbreviation H-R diagram or HRD, also known as a Colour-Magnitude diagram, or CMD) shows the relationship between absolute magnitude, luminosity, classification, and effective temperature of stars. ... For other uses, see Temperature (disambiguation). ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ...

The Hertzsprung-Russell diagram; the main sequence is from bottom right to top left.

It is believed that the Sun's position on the main sequence puts it in the "prime of life" for a star, in that it has not yet exhausted its store of hydrogen for nuclear fusion. The Sun is growing brighter; early in its history it was 75 percent as bright as it is today.[26] Image File history File links Size of this preview: 534 × 599 pixelsFull resolution (723 × 811 pixel, file size: 26 KB, MIME type: image/gif) Hertzsprung-Russell Diagram from Richard Powells diagram at http://(remove this, site is blacklisted)anzwers. ... Image File history File links Size of this preview: 534 × 599 pixelsFull resolution (723 × 811 pixel, file size: 26 KB, MIME type: image/gif) Hertzsprung-Russell Diagram from Richard Powells diagram at http://(remove this, site is blacklisted)anzwers. ... The Hertzsprung-Russell diagram (usually referred to by the abbreviation H-R diagram or HRD, also known as a Colour-Magnitude diagram, or CMD) shows the relationship between absolute magnitude, luminosity, classification, and effective temperature of stars. ...


Calculations of the ratios of hydrogen and helium within the Sun suggest it is halfway through its life cycle. It will eventually move off the main sequence and become larger, brighter, cooler and redder, becoming a red giant in about five billion years.[27] At that point its luminosity will be several thousand times its present value. General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... According to the Hertzsprung-Russell diagram, a red giant is a large non-main sequence star of stellar classification K or M; so-named because of the reddish appearance of the cooler giant stars. ... This article does not cite any references or sources. ...


The Sun is a population I star; it was born in the later stages of the universe's evolution. It contains more elements heavier than hydrogen and helium ("metals" in astronomical parlance) than older population II stars.[28] Elements heavier than hydrogen and helium were formed in the cores of ancient and exploding stars, so the first generation of stars had to die before the universe could be enriched with these atoms. The oldest stars contain few metals, while stars born later have more. This high metallicity is thought to have been crucial to the Sun's developing a planetary system, because planets form from accretion of metals.[29] The globular cluster M80. ... For other uses, see Universe (disambiguation). ... The globular cluster M80. ... The structure of the Sun The core of the Sun is considered to extend from the center to about 0. ... An artists concept of a protoplanetary disc. ...


Interplanetary medium

Main article: Interplanetary medium

Along with light, the Sun radiates a continuous stream of charged particles (a plasma) known as the solar wind. This stream of particles spreads outwards at roughly 1.5 million kilometres per hour,[30] creating a tenuous atmosphere (the heliosphere) that permeates the Solar System out to at least 100 AU (see heliopause). This is known as the interplanetary medium. The Sun's 11-year sunspot cycle and frequent solar flares and coronal mass ejections disturb the heliosphere, creating space weather.[31] The Sun's rotating magnetic field acts on the interplanetary medium to create the heliospheric current sheet, the largest structure in the solar system.[32] Heliospheric current sheet, the largest structure in the Solar System, results from the influence of the Suns rotating magnetic field on the plasma in the interplanetary medium (Solar Wind) [1]. (click to enlarge) The interplanetary medium is the material which fills the solar system and through which all the... Image File history File links Size of this preview: 768 × 600 pixelsFull resolution (866 × 676 pixel, file size: 172 KB, MIME type: image/gif) (All user names refer to en. ... Image File history File links Size of this preview: 768 × 600 pixelsFull resolution (866 × 676 pixel, file size: 172 KB, MIME type: image/gif) (All user names refer to en. ... Heliospheric current sheet The Heliospheric current sheet (HCS) is the surface within the Solar System where the polarity of the Suns magnetic field changes from north to south. ... For other uses, see Light (disambiguation). ... For other uses, see Plasma. ... The plasma in the solar wind meeting the heliopause The solar wind is a stream of charged particles (i. ... The heliosphere is a bubble in space produced by the solar wind. ... Heliospheric current sheet, the largest structure in the Solar System, results from the influence of the Suns rotating magnetic field on the plasma in the interplanetary medium (Solar Wind) [1]. (click to enlarge) The interplanetary medium is the material which fills the solar system and through which all the... It has been suggested that this article or section be merged with Schwabe-Wolf cycle. ... A solar flare observed by Hinode in the G-band. ... A composite image showing two CMEs (at 2 oclock and 8 oclock), with the sun at center. ... Aurora australis observed by Discovery, May 1991. ... Heliospheric current sheet The Heliospheric current sheet (HCS) is the surface within the Solar System where the polarity of the Suns magnetic field changes from north to south. ...

Aurora australis seen from orbit.
Aurora australis seen from orbit.

Earth's magnetic field protects its atmosphere from interacting with the solar wind. Venus and Mars do not have magnetic fields, and the solar wind causes their atmospheres to gradually bleed away into space.[33] The interaction of the solar wind with Earth's magnetic field creates the aurorae seen near the magnetic poles. Download high resolution version (874x576, 51 KB)NASA image of aurora australis taken from Space Shuttle in May 1991. ... Download high resolution version (874x576, 51 KB)NASA image of aurora australis taken from Space Shuttle in May 1991. ... Aurora borealis Polar aurorae are optical phenomena characterized by colorful displays of light in the night sky. ... The magnetosphere shields the surface of the Earth from the charged particles of the solar wind. ... Air redirects here. ... The Aurora Borealis, or Northern Lights, shines above Bear Lake Aurora Borealis as seen over Canada at 11,000m (36,000 feet) Red and green Aurora in Fairbanks, Alaska Aurora Borealis redirects here. ... The magnetosphere shields the surface of the Earth from the charged particles of the solar wind. ...


Cosmic rays originate outside the Solar System. The heliosphere partially shields the Solar System, and planetary magnetic fields (for planets which have them) also provide some protection. The density of cosmic rays in the interstellar medium and the strength of the Sun's magnetic field change on very long timescales, so the level of cosmic radiation in the Solar System varies, though by how much is unknown.[34] Cosmic rays can loosely be defined as energetic particles originating outside of the Earth. ... The interstellar medium (or ISM) is the name astronomers give to the tenuous gas and dust that pervade interstellar space. ...


The interplanetary medium is home to at least two disc-like regions of cosmic dust. The first, the zodiacal dust cloud, lies in the inner Solar System and causes zodiacal light. It was likely formed by collisions within the asteroid belt brought on by interactions with the planets.[35] The second extends from about 10 AU to about 40 AU, and was probably created by similar collisions within the Kuiper belt.[36][37] “Space dust” redirects here. ... Interplanetary dust cloud The interplanetary dust cloud has been studied for many years in order to understand its nature, origin, and relationship to solar systems (our own, as well as extrasolar systems). ... The zodiacal light in the eastern sky before the beginning of morning twilight. ...


Inner Solar System

The inner Solar System is the traditional name for the region comprising the terrestrial planets and asteroids. Composed mainly of silicates and metals, the objects of the inner Solar System huddle very closely to the Sun; the radius of this entire region is shorter than the distance between Jupiter and Saturn. This region was, in old parlance, denoted inner space; the area outside the asteroid belt was denoted outer space. In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. ...


Inner planets

Main article: Terrestrial planet
The inner planets. From left to right: Mercury, Venus, Earth, and Mars (sizes to scale)
The inner planets. From left to right: Mercury, Venus, Earth, and Mars (sizes to scale)

The four inner or terrestrial planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of minerals with high melting points, such as the silicates which form their solid crusts and semi-liquid mantles, and metals such as iron and nickel, which form their cores. Three of the four inner planets (Venus, Earth and Mars) have substantial atmospheres; all have impact craters and tectonic surface features such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets which are closer to the Sun than Earth is (i.e. Mercury and Venus). The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... Image File history File linksMetadata Download high resolution version (1500x653, 488 KB)Terrestrial planet size comparisons. ... Image File history File linksMetadata Download high resolution version (1500x653, 488 KB)Terrestrial planet size comparisons. ... This article is about the planet. ... For other uses, see Venus (disambiguation). ... This article is about Earth as a planet. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... Rock redirects here. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. ... Earth cutaway from core to exosphere. ... Earth cutaway from core to exosphere. ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... For other uses, see Nickel (disambiguation). ... The planetary core consists of the innermost layer(s) of a planet. ... For other uses, see Atmosphere (disambiguation). ... Tycho crater on Earths moon. ... The tectonic plates of the world were mapped in the second half of the 20th century. ... African Rift Valley. ... Cleveland Volcano in the Aleutian Islands of Alaska photographed from the International Space Station For other uses, see Volcano (disambiguation). ... The terms inferior planet and superior planet were coined by Copernicus to distinguish a planets orbits size in relation to the Earths. ...

Mercury
Mercury (0.4 AU) is the closest planet to the Sun and the smallest planet (0.055 Earth masses). Mercury has no natural satellites, and its only known geological features besides impact craters are "wrinkle-ridges", probably produced by a period of contraction early in its history.[38] Mercury's almost negligible atmosphere consists of atoms blasted off its surface by the solar wind.[39] Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, and that it was prevented from fully accreting by the young Sun's energy.[40][41]
Venus
Venus (0.7 AU) is close in size to Earth (0.815 Earth masses) and, like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere and evidence of internal geological activity. However, it is much drier than Earth and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C, most likely due to the amount of greenhouse gases in the atmosphere.[42] No definitive evidence of current geological activity has been detected on Venus, but it has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is regularly replenished by volcanic eruptions.[43]
Earth
Earth (1 AU) is the largest and densest of the inner planets, the only one known to have current geological activity, and the only planet known to have life. Its liquid hydrosphere is unique among the terrestrial planets, and it is also the only planet where plate tectonics has been observed. Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen.[44] It has one satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System.
Mars
Mars (1.5 AU) is smaller than Earth and Venus (0.107 Earth masses). It possesses a tenuous atmosphere of mostly carbon dioxide. Its surface, peppered with vast volcanoes such as Olympus Mons and rift valleys such as Valles Marineris, shows geological activity that may have persisted until very recently. Its red color comes from rust in its iron-rich soil.[45] Mars has two tiny natural satellites (Deimos and Phobos) thought to be captured asteroids.[46]

This article is about the planet. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... A wrinkle-ridge is a type of feature commonly found on Lunar mares. ... For other uses, see Venus (disambiguation). ... For other uses, see Celsius (disambiguation). ... Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... This article is about Earth as a planet. ... This article is about life in general. ... The movement of water around, over, and through the Earth is called the water cycle, a key process of the hydrosphere. ... The tectonic plates of the world were mapped in the second half of the 20th century. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colourless (gas) colourless (liquid) Standard atomic weight 15. ... This article is about Earths moon. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... This article is about the volcano on Mars and Solar Systems tallest mountain in Latin, For other uses, see Olympus (disambiguation). ... Valles Marineris cuts a wide swath across the face of Mars Valles Marineris (Latin for Mariner Valley, named after the Mariner 9 Mars orbiter of 1971-72 which discovered it. ... Deimos (IPA or ; Greek Δείμος: Dread), is the smaller and outermost of Mars’ two moons, named after Deimos from Greek Mythology. ... Phobos (IPA: or [ˈfoÊŠ.bÉ™s]) (systematic designation: ) is the larger and closer of Mars two moons (the other being Deimos). ... For other uses, see Asteroid (disambiguation). ...

Asteroid belt

Main article: Asteroid belt
Image of the main asteroid belt and the Trojan asteroids
Image of the main asteroid belt and the Trojan asteroids

Asteroids are mostly small Solar System bodies composed mainly of rocky and metallic non-volatile minerals. For other uses, see Asteroid (disambiguation). ... Image File history File links Download high-resolution version (768x768, 188 KB)The inner Solar System, from the Sun to Jupiter. ... Image File history File links Download high-resolution version (768x768, 188 KB)The inner Solar System, from the Sun to Jupiter. ... For other uses, see Asteroid (disambiguation). ...


The main asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter.


Asteroids range in size from hundreds of kilometres across to microscopic. All asteroids save the largest, Ceres, are classified as small Solar System bodies, but some asteroids such as Vesta and Hygieia may be reclassed as dwarf planets if they are shown to have achieved hydrostatic equilibrium. Spectral type: G[8] Absolute magnitude: 3. ... 4 Vesta (ves-ta) is the second most massive asteroid in the asteroid belt, with a mean diameter of about 530 km and an estimated mass 12% the mass of the entire asteroid belt. ... 10 Hygiea (hye-jee-a or hi-jee-a) is the fourth largest Main belt asteroid with a diameter of 407 km. ... Hydrostatic equilibrium occurs when compression due to gravity is balanced by a pressure gradient which creates a pressure gradient force in the opposite direction. ...


The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter.[47] Despite this, the total mass of the main belt is unlikely to be more than a thousandth of that of the Earth.[48] The main belt is very sparsely populated; spacecraft routinely pass through without incident. Asteroids with diameters between 10 and 10-4 m are called meteoroids.[49] Technicians work on the Ulysses space probe. ... This article is about the unit of length. ... “Meteor” redirects here. ...

Ceres
Ceres
Ceres
Ceres (2.77 AU) is the largest body in the asteroid belt and is classified as a dwarf planet. It has a diameter of slightly under 1000 km, large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in the 19th century, but was reclassified as an asteroid in the 1850s as further observation revealed additional asteroids.[50] It was again reclassified in 2006 as a dwarf planet.
Asteroid groups
Asteroids in the main belt are divided into asteroid groups and families based on their orbital characteristics. Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners. The asteroid belt also contains main-belt comets[51] which may have been the source of Earth's water.

Trojan asteroids are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term "Trojan" is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits. Image File history File linksMetadata Ceres_optimized. ... Image File history File linksMetadata Ceres_optimized. ... Spectral type: G[8] Absolute magnitude: 3. ... Artists impression of Pluto (background) and Charon (foreground). ... Minor planet is the official term for asteroids and trans-Neptunian objects. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... Main-belt comets are bodies orbiting within the (main) asteroid belt which show cometary activity during a part of their orbit. ... Image of the Trojan asteroids in front of and behind Jupiter along its orbital path. ... A contour plot of the effective potential (the Hills Surfaces) of a two-body system (the Sun and Earth here), showing the five Lagrange points. ... Hilda asteroids are asteroids with a semi-major axis between 3. ... In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other. ...


The inner Solar System is also dusted with rogue asteroids, many of which cross the orbits of the inner planets. Computer model of the Apollo Asteroid 6489 Golevka Near-Earth asteroids (NEAs) are asteroids whose orbits are close to Earths orbit. ...


Mid Solar System

The middle region of the Solar System is home to the gas giants and their planet-sized satellites. Many short period comets, including the centaurs, also lie in this region. It has no traditional name; it is occasionally referred to as the "outer Solar System", although recently that term has been more often applied to the region beyond Neptune. The solid objects in this region are composed of a higher proportion of "ices" (water, ammonia, methane) than the rocky denizens of the inner Solar System. The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ...


Outer planets

Main article: Gas giant
From top to bottom: Neptune, Uranus, Saturn, and Jupiter (not to scale)
From top to bottom: Neptune, Uranus, Saturn, and Jupiter (not to scale)

The four outer planets, or gas giants (sometimes called Jovian planets), collectively make up 99 percent of the mass known to orbit the Sun. Jupiter and Saturn's atmospheres are largely hydrogen and helium. Uranus and Neptune's atmospheres have a higher percentage of “ices”, such as water, ammonia and methane. Some astronomers suggest they belong in their own category, “ice giants.”[52] All four gas giants have rings, although only Saturn's ring system is easily observed from Earth. The term outer planet should not be confused with superior planet, which designates planets outside Earth's orbit (the outer planets and Mars). This article does not cite any references or sources. ... Image File history File links Download high resolution version (509x655, 33 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): European Space Operations Centre Gas giant Solar system Encyclopedia Astronautica Meteoroid Marshall Space Flight Center Stanford torus EADS... Image File history File links Download high resolution version (509x655, 33 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): European Space Operations Centre Gas giant Solar system Encyclopedia Astronautica Meteoroid Marshall Space Flight Center Stanford torus EADS... This article does not cite any references or sources. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Ammonia (disambiguation). ... Methane is a chemical compound with the molecular formula . ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... The terms inferior planet and superior planet were coined by Copernicus to distinguish a planets orbits size in relation to the Earths. ...

Jupiter
Jupiter (5.2 AU), at 318 Earth masses, masses 2.5 times all the other planets put together. It is composed largely of hydrogen and helium. Jupiter's strong internal heat creates a number of semi-permanent features in its atmosphere, such as cloud bands and the Great Red Spot. Jupiter has sixty-three known satellites. The four largest, Ganymede, Callisto, Io, and Europa, show similarities to the terrestrial planets, such as volcanism and internal heating.[53] Ganymede, the largest satellite in the Solar System, is larger than Mercury.
Saturn
Saturn (9.5 AU), famous for its extensive ring system, has similarities to Jupiter, such as its atmospheric composition. Saturn is far less massive, being only 95 Earth masses. Saturn has sixty known satellites (and 3 unconfirmed); two of which, Titan and Enceladus, show signs of geological activity, though they are largely made of ice.[54] Titan is larger than Mercury and the only satellite in the Solar System with a substantial atmosphere.
Uranus
Uranus (19.6 AU), at 14 Earth masses, is the lightest of the outer planets. Uniquely among the planets, it orbits the Sun on its side; its axial tilt is over ninety degrees to the ecliptic. It has a much colder core than the other gas giants, and radiates very little heat into space.[55] Uranus has twenty-seven known satellites, the largest ones being Titania, Oberon, Umbriel, Ariel and Miranda.
Neptune
Neptune (30 AU), though slightly smaller than Uranus, is more massive (equivalent to 17 Earths) and therefore denser. It radiates more internal heat, but not as much as Jupiter or Saturn.[56] Neptune has thirteen known satellites. The largest, Triton, is geologically active, with geysers of liquid nitrogen.[57] Triton is the only large satellite with a retrograde orbit. Neptune is accompanied in its orbit by a number of minor planets in a 1:1 resonance with it, termed Neptune Trojans.

For other uses, see Jupiter (disambiguation). ... This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... A false-color image of the Great Red Spot of Jupiter from Voyager 1. ... Jupiters 4 Galilean moons, in a composite image comparing their sizes and the size of Jupiter (Great Red Spot visible). ... This article is about the natural satellite of Jupiter. ... There is also an asteroid named 204 Kallisto. ... Atmosphere Surface pressure: trace Composition: 90% sulfur dioxide Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter and, with a diameter of 3,642 kilometers, is the fourth largest moon in the Solar System. ... Apparent magnitude: 5. ... This article is about the planet. ... The full set of rings, photographed as Saturn eclipsed the sun from the vantage of the Cassini spacecraft on September 15, 2006 (brightness has been exaggerated in this image). ... The Saturnian system (photographic montage) Saturn has 60 confirmed natural satellites, plus three hypothetical moons. ... Titan (, from Ancient Greek Τῑτάν) or Saturn VI is the largest moon of Saturn and the only moon known to have a dense atmosphere. ... Atmosphere Surface pressure: trace, significant spatial variability[8][9] Composition: 91% Water vapour 4% Nitrogen 3. ... Ganesa Macula, a dark feature on Saturns moon Titan, might be a cryovolcanic dome. ... For other uses, see Uranus (disambiguation). ... In astronomy, axial tilt is the inclination angle of a planets rotational axis in relation to a perpendicular to its orbital plane. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... Uranus has 27 known moons. ... Atmospheric pressure   Titania (ti-taan-ee-É™ or tye-tan-ee-É™) is the largest moon of Uranus. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ... Atmospheric pressure 0 kPa Umbriel (um-bree-É™l, IPA ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... Atmospheric pressure 0 kPa Ariel (air-ee-É™l, IPA ) is a moon of Uranus discovered on 24 October 1851 by William Lassell. ... Miranda (IPA: ) is the smallest and innermost of Uranus five major moons. ... For other uses, see Neptune (disambiguation). ... For other uses, see Mass (disambiguation). ... For other uses, see Density (disambiguation). ... Neptune (top) and Triton (bottom), 3 days after the Voyager 2 flyby. ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... Strokkur geyser, Iceland A geyser is a type of hot spring that erupts periodically, ejecting a column of hot water and steam into the air. ... A tank of liquid nitrogen, used to supply a cryogenic freezer (for storing laboratory samples at a temperature of about -150 Celsius). ... Direct motion is the motion of a planetary body in a direction similar to that of other bodies within its system, and is sometimes called prograde motion. ... Minor planets, or asteroids or planetoids, are minor celestial bodies of the Solar system orbiting the Sun (mostly Small solar system bodies) that are smaller than major planets, but larger than meteoroids (commonly defined as being 10 meters across or less[1]), and that are not comets. ... In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other. ... As of March 2007, there are five[1] known Neptune Trojans (named by analogy to the Trojan asteroids) which have the same orbital period as the planet. ...

Comets

Main article: Comet
Comet Hale-Bopp
Comet Hale-Bopp

Comets are small Solar System bodies, usually only a few kilometres across, composed largely of volatile ices. They have highly eccentric orbits, generally a perihelion within the orbits of the inner planets and an aphelion far beyond Pluto. When a comet enters the inner Solar System, its proximity to the Sun causes its icy surface to sublimate and ionise, creating a coma: a long tail of gas and dust often visible to the naked eye. Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... Image File history File links Comet_c1995o1. ... Image File history File links Comet_c1995o1. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article does not cite any references or sources. ... This article is about the electrically charged particle. ... The comet Ikeya-Zhang exhibiting a bright, condensed coma (march 2002) In astronomy, the nebulous envelope around the nucleus of a comet is called its coma (from the Latin word for hair). It is formed when the comet passes close to the sun on its highly elliptical orbit; as the...


Short-period comets have orbits lasting less than two hundred years. Long-period comets have orbits lasting thousands of years. Short-period comets are believed to originate in the Kuiper belt, while long-period comets, such as Hale-Bopp, are believed to originate in the Oort cloud. Many comet groups, such as the Kreutz Sungrazers, formed from the breakup of a single parent.[58] Some comets with hyperbolic orbits may originate outside the Solar System, but determining their precise orbits is difficult.[59] Old comets that have had most of their volatiles driven out by solar warming are often categorised as asteroids.[60] The Kuiper belt, derived from data from the Minor Planet Center. ... Comet Hale-Bopp (formally designated C/1995 O1) was probably the most widely observed comet of the twentieth century, and one of the brightest seen for many decades. ... Artists rendering of the Oort cloud and the Kuiper Belt. ... SOHO spots a Kreutz Sungrazer with a prominent tail, plunging towards the Sun The Kreutz Sungrazers are a family of comets characterized by orbits taking them extremely close to the Sun at perihelion. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ...

Centaurs
The centaurs, which extend from 9 to 30 AU, are icy comet-like bodies that orbit in the region between Jupiter and Neptune. The largest known centaur, 10199 Chariklo, has a diameter of between 200 and 250 km.[61] The first centaur discovered, 2060 Chiron, has been called a comet since it develops a coma just as comets do when they approach the Sun.[62] Some astronomers classify centaurs as inward-scattered Kuiper belt objects along with the outward-scattered residents of the scattered disc.[63]

The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... 10199 Chariklo (provisional designation: 1997 CU26) is known as a centaur because it orbits between Saturn and Uranus. ... 2060 Chiron (IPA: ) is an object in the outer solar system with an orbit between those of Saturn and Uranus and a radius of 71±5 km [1]. Although it was initially classified as an asteroid, later dispute arose as to whether it was an asteroid or actually a comet. ...

Trans-Neptunian region

The area beyond Neptune, or the "trans-Neptunian region", is still largely unexplored. It appears to consist overwhelmingly of small worlds (the largest having a diameter only a fifth that of the Earth and a mass far smaller than that of the Moon) composed mainly of rock and ice. This region is sometimes known as the "outer Solar System", though others use that term to mean the region beyond the asteroid belt. A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... Timeline of solar system exploration organized by date of launch. ... For other uses, see Asteroid (disambiguation). ...


Kuiper belt

Main article: Kuiper belt
Plot of all known Kuiper belt objects, set against the four outer planets
Plot of all known Kuiper belt objects, set against the four outer planets

The Kuiper belt, the region's first formation, is a great ring of debris similar to the asteroid belt, but composed mainly of ice. It extends between 30 and 50 AU from the Sun. This region is thought to be the source of short-period comets. It is composed mainly of small Solar System bodies, but many of the largest Kuiper belt objects, such as Quaoar, Varuna, (136108) 2003 EL61, (136472) 2005 FY9 and Orcus, may be reclassified as dwarf planets. There are estimated to be over 100,000 Kuiper belt objects with a diameter greater than 50 km, but the total mass of the Kuiper belt is thought to be only a tenth or even a hundredth the mass of the Earth.[64] Many Kuiper belt objects have multiple satellites, and most have orbits that take them outside the plane of the ecliptic. The Kuiper belt, derived from data from the Minor Planet Center. ... Image File history File links Size of this preview: 611 × 599 pixelsFull resolution (2708 × 2656 pixel, file size: 314 KB, MIME type: image/png) Legend Red = The Sun Aquamarine = Giant Planet Green = Kuiper Belt Object Orange = Scattered Disk object or Centaur Pink = Trojan of Jupiter Yellow = Trojan of Neptune Axes... Image File history File links Size of this preview: 611 × 599 pixelsFull resolution (2708 × 2656 pixel, file size: 314 KB, MIME type: image/png) Legend Red = The Sun Aquamarine = Giant Planet Green = Kuiper Belt Object Orange = Scattered Disk object or Centaur Pink = Trojan of Jupiter Yellow = Trojan of Neptune Axes... 50000 Quaoar (pronounced kwaa·waar or kwow·ər, English IPA: , Tongva ) [2] is a Trans-Neptunian object orbiting the Sun in the Kuiper belt. ... 20000 Varuna (VAR oo na) is a large classical Kuiper Belt object (KBO). ... (also written (136108) 2003 EL61), nicknamed Easter Bunny, is a large Kuiper belt object, roughly one-third the mass of Pluto, discovered by J. L. Ortiz et al. ... (also written (136472) 2005 FY9) is a very large Kuiper belt object, and one of the two largest among the population in the classical KBO orbits. ... 90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. ...

Diagram showing the resonant and classical Kuiper belt
Diagram showing the resonant and classical Kuiper belt

The Kuiper belt can be roughly divided into the "resonant" belt and the "classical" belt. The resonant belt consists of objects with orbits linked to that of Neptune (e.g. orbiting twice for every three Neptune orbits, or once for every two). The resonant belt actually begins within the orbit of Neptune itself. The classical belt consists of objects having no resonance with Neptune, and extends from roughly 39.4 AU to 47.7 AU.[65] Members of the classical Kuiper belt are classified as cubewanos, after the first of their kind to be discovered, (15760) 1992 QB1.[66] Image File history File links TheKuiperBelt_Projections_55AU_Classical_Plutinos. ... Image File history File links TheKuiperBelt_Projections_55AU_Classical_Plutinos. ... In astronomy, a resonant Trans-Neptunian Object is a Trans-Neptunian Object (TNO) in mean motion orbital resonance with Neptune. ... In astronomy a cubewano (pronounced ) is a Kuiper belt object that orbits beyond Neptune and is not controlled by an orbital resonance with the giant planet. ... In astronomy a cubewano (pronounced ) is a Kuiper belt object that orbits beyond Neptune and is not controlled by an orbital resonance with the giant planet. ... (15760) 1992 QB1 (also written (15760) 1992 QB1) was the first trans-Neptunian object to be discovered after Pluto and Charon. ...

Pluto and Charon
Pluto (39 AU average), a dwarf planet, is the largest known object in the Kuiper belt. When discovered in 1930 it was considered to be the ninth planet; this changed in 2006 with the adoption of a formal definition of planet. Pluto has a relatively eccentric orbit inclined 17 degrees to the ecliptic plane and ranging from 29.7 AU from the Sun at perihelion (within the orbit of Neptune) to 49.5 AU at aphelion.
Pluto and its three known moons
Pluto and its three known moons
It is unclear whether Charon, Pluto's largest moon, will continue to be classified as such or as a dwarf planet itself. Both Pluto and Charon orbit a barycenter of gravity above their surfaces, making Pluto-Charon a binary system. Two much smaller moons, Nix and Hydra, orbit Pluto and Charon.
Pluto lies in the resonant belt, having a 3:2 resonance with Neptune (it orbits twice round the Sun for every three Neptunian orbits). Kuiper belt objects whose orbits share this resonance are called plutinos.[67]

For other uses, see Pluto (disambiguation). ... Photograph of the planet Neptune and its moon Triton, taken by Voyager 2 as it entered the outer solar system. ... Image File history File linksMetadata Download high-resolution version (1085x1095, 118 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Solar System Pluto User:Wahkeenah Plutos natural satellites Talk:Plutos natural satellites User:Appraiser User:JohnnyBGood... Image File history File linksMetadata Download high-resolution version (1085x1095, 118 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Solar System Pluto User:Wahkeenah Plutos natural satellites Talk:Plutos natural satellites User:Appraiser User:JohnnyBGood... Charon (shair-ən or kair-ən (key), IPA , Greek Χάρων), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... In physics, the center of mass of a system of particles is a specific point at which, for many purposes, the systems mass behaves as if it were concentrated. ... A binary system is an astronomy term referring to two objects in space, usually stars, which are so close that their gravitational forces attract one another into a mutual orbit. ... Nix (formerly known as S/2005 P 2), is a natural satellite of Pluto. ... Hydra (formerly known as S/2005 P 1) is a natural satellite of Pluto. ... In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other. ... In astronomy, a plutino is a trans-Neptunian object that has a 3:2 orbital resonance with Neptune. ...

Scattered disc

Main article: Scattered disc
Black: scattered; blue: classical; green: resonant
Black: scattered; blue: classical; green: resonant

The scattered disc overlaps the Kuiper belt but extends much further outwards. Scattered disc objects are believed to come from the Kuiper belt, having been ejected into erratic orbits by the gravitational influence of Neptune's early outward migration. Most scattered disc objects (SDOs) have perihelia within the Kuiper belt but aphelia as far as 150 AU from the Sun. SDOs' orbits are also highly inclined to the ecliptic plane, and are often almost perpendicular to it. Some astronomers consider the scattered disc to be merely another region of the Kuiper belt, and describe scattered disc objects as "scattered Kuiper belt objects."[68] Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ... Image File history File links TheKuiperBelt_Projections_100AU_Classical_SDO.svg // Summary Projection of the aligned orbits of the scattered, classical and resonant objects. ... Image File history File links TheKuiperBelt_Projections_100AU_Classical_SDO.svg // Summary Projection of the aligned orbits of the scattered, classical and resonant objects. ... The theories concerning the formation and evolution of the Solar System are complex and varied, interweaving various scientific disciplines, from astronomy and physics to geology and planetary science. ...

Eris and its moon Dysnomia
Eris and its moon Dysnomia
Eris
Eris (68 AU average) is the largest known scattered disc object, and caused a debate about what constitutes a planet, since it is at least 5% larger than Pluto with an estimated diameter of 2400 km (1500 mi). It is the largest of the known dwarf planets.[69] It has one moon, Dysnomia. Like Pluto, its orbit is highly eccentric, with a perihelion of 38.2 AU (roughly Pluto's distance from the Sun) and an aphelion of 97.6 AU, and steeply inclined to the ecliptic plane.

Image File history File linksMetadata No higher resolution available. ... Image File history File linksMetadata No higher resolution available. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... Absolute magnitude: −1. ... Photograph of the planet Neptune and its moon Triton, taken by Voyager 2 as it entered the outer solar system. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ...

Farthest regions

The point at which the Solar System ends and interstellar space begins is not precisely defined, since its outer boundaries are shaped by two separate forces: the solar wind and the Sun's gravity. The solar wind is believed to surrender to the interstellar medium at roughly four times Pluto's distance. However, the Sun's Roche sphere, the effective range of its gravitational influence, is believed to extend up to a thousand times farther. The interstellar medium (or ISM) is the name astronomers give to the tenuous gas and dust that pervade interstellar space. ... A Hill sphere approximates the gravitational sphere of influence of one astronomical body in the face of perturbations from another heavier body around which it orbits. ...


Heliopause

The Voyagers entering the heliosheath
The Voyagers entering the heliosheath

The heliosphere is divided into two separate regions. The solar wind travels at its maximum velocity out to about 95 AU, or three times the orbit of Pluto. The edge of this region is the termination shock, the point at which the solar wind collides with the opposing winds of the interstellar medium. Here the wind slows, condenses and becomes more turbulent, forming a great oval structure known as the heliosheath that looks and behaves very much like a comet's tail, extending outward for a further 40 AU at its stellar-windward side, but tailing many times that distance in the opposite direction. The outer boundary of the heliosphere, the heliopause, is the point at which the solar wind finally terminates, and is the beginning of interstellar space.[70] Image File history File linksMetadata Download high resolution version (2500x1687, 1789 KB) original description: This still shows the locations of Voyagers 1 and 2. ... Image File history File linksMetadata Download high resolution version (2500x1687, 1789 KB) original description: This still shows the locations of Voyagers 1 and 2. ... Voyager Project redirects here. ... The locations of Voyagers 1 and 2 as of 2005 The heliosheath is the zone between the termination shock and the heliopause at the outer border of the solar system. ... The heliosphere is a bubble in space produced by the solar wind. ... The locations of Voyagers 1 and 2 as of 2005 In space physics, the termination shock is the boundary marking one of the outer limits of the suns influence. ... The interstellar medium (or ISM) is the name astronomers give to the tenuous gas and dust that pervade interstellar space. ... The locations of Voyagers 1 and 2 as of 2005 The heliosheath is the zone between the termination shock and the heliopause at the outer border of the solar system. ... The heliopause is the boundary between the heliosphere and the interstellar medium outside the solar system. ...


The shape and form of the outer edge of the heliosphere is likely affected by the fluid dynamics of interactions with the interstellar medium,[71] as well as solar magnetic fields prevailing to the south, e.g. it is bluntly shaped with the northern hemisphere extending 9 AU (roughly 900 million miles) farther than the southern hemisphere. Beyond the heliopause, at around 230 AU, lies the bow shock, a plasma "wake" left by the Sun as it travels through the Milky Way.[72] Fluid dynamics is the sub-discipline of fluid mechanics dealing with fluids (liquids and gases) in motion. ... In a planetary magnetosphere, the bow shock is the boundary at which the solar wind abruptly drops as a result of its approach to the magnetopause. ... For other uses, see Milky Way (disambiguation). ...


No spacecraft have yet passed beyond the heliopause, so it is impossible to know for certain the conditions in local interstellar space. How well the heliosphere shields the Solar System from cosmic rays is poorly understood. A dedicated mission beyond the heliosphere has been suggested.[73][74]


Oort cloud

Main article: Oort cloud
Artist's rendering of the Kuiper Belt and hypothetical Oort cloud
Artist's rendering of the Kuiper Belt and hypothetical Oort cloud

The hypothetical Oort cloud is a great mass of up to a trillion icy objects that is believed to be the source for all long-period comets and to surround the Solar System at around 50 AU, and extending out to roughly 50,000 AU (around 1 LY), and possibly to as far as 100,000 AU (1.8 LY). It is believed to be composed of comets which were ejected from the inner Solar System by gravitational interactions with the outer planets. Oort cloud objects move very slowly, and can be perturbed by infrequent events such as collisions, the gravitational effects of a passing star, or the galactic tide.[75][76] Artists rendering of the Oort cloud and the Kuiper Belt. ... Image File history File links Kuiper_oort. ... Image File history File links Kuiper_oort. ... Artists rendering of the Oort cloud and the Kuiper Belt. ... A light-year, symbol ly, is the distance light travels in one year: exactly 9. ... The Andromeda Galaxy. ...

Telescopic image of Sedna
Telescopic image of Sedna

Sedna and the inner Oort cloud Download high resolution version (874x665, 198 KB)Image of Sedna from BBC web site (http://news. ... Download high resolution version (874x665, 198 KB)Image of Sedna from BBC web site (http://news. ...

90377 Sedna is a large, reddish Pluto-like object with a gigantic, highly elliptical orbit that takes it from about 76 AU at perihelion to 928 AU at aphelion and takes 12,050 years to complete. Mike Brown, who discovered the object in 2003, asserts that it cannot be part of the scattered disc or the Kuiper belt as its perihelion is too distant to have been affected by Neptune's migration. He and other astronomers consider it to be the first in an entirely new population, which also may include the object 2000 CR105, which has a perihelion of 45 AU, an aphelion of 415 AU, and an orbital period of 3420 years.[77] Brown terms this population the "Inner Oort cloud," as it may have formed through a similar process, although it is far closer to the Sun.[78] Sedna is very likely a dwarf planet, though its shape has yet to be determined with certainty.

you are abunch of bull | bgcolour=#FFFFC0 | name=90377 Sedna | image= | caption= Sedna is located in the center of the green circle | discovery=yes | discoverer=M. Brown, C. Trujillo, D. Rabinowitz | discovered=November 14, 2003 | mp_name=90377 Sedna | alt_names= | mp_category=Trans-Neptunian object | epoch=September 26, 1990 (JD 2448160. ... Michael (Mike) E. Brown (born c. ... Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ... The Kuiper belt, derived from data from the Minor Planet Center. ... 2000 CR105 is the third most distant known object in the solar system after 2003 UB313 and 90377 Sedna. ...

Boundaries

See also: Hypothetical planet

Much of our Solar System is still unknown. The Sun's gravitational field is estimated to dominate the gravitational forces of surrounding stars out to about two light years (125,000 AU). The outer extent of the Oort cloud, by contrast, may not extend farther than 50,000 AU.[79] Despite discoveries such as Sedna, the region between the Kuiper belt and the Oort cloud, an area tens of thousands of AU in radius, is still virtually unmapped. There are also ongoing studies of the region between Mercury and the Sun.[80] Objects may yet be discovered in the Solar System's uncharted regions. An artists rendering of a hypothetical exoplanet. ... This list of the nearest stars to Earth is ordered by increasing distance out to a maximum of 5 parsecs (16. ...


Galactic context

Location of the Solar System within our galaxy
Location of the Solar System within our galaxy

The Solar System is located in the Milky Way galaxy, a barred spiral galaxy with a diameter of about 100,000 light-years containing about 200 billion stars.[81] Our Sun resides in one of the Milky Way's outer spiral arms, known as the Orion Arm or Local Spur.[82] The Sun lies between 25,000 and 28,000 light years from the Galactic Centre, and its speed within the galaxy is about 220 kilometres per second, so that it completes one revolution every 225–250 million years. This revolution is known as the Solar System's galactic year.[83] Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... For other uses, see Milky Way (disambiguation). ... For other uses, see Galaxy (disambiguation). ... NGC 1300, viewed nearly face-on. ... A light-year, symbol ly, is the distance light travels in one year: exactly 9. ... Observed structure of the Milky Ways spiral arms The Orion Arm or Local Arm (labeled 0) is a minor, spiral arm of the Milky Way galaxy. ... The Galactic Center is the rotational center of the Milky Way galaxy. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... // Galactic time NGC 4414, a typical spiral galaxy alike our Milky Way Galactic time, not to confuse with siderial time, is the time that is described by our spin relative to the center of the galaxy. ...


The Solar System's location in the galaxy is very likely a factor in the evolution of life on Earth. Its orbit is close to being circular and is at roughly the same speed as that of the spiral arms, which means it passes through them only rarely. Since spiral arms are home to a far larger concentration of potentially dangerous supernovae, this has given Earth long periods of interstellar stability for life to evolve.[84] The Solar System also lies well outside the star-crowded environs of the galactic centre. Near the centre, gravitational tugs from nearby stars could perturb bodies in the Oort Cloud and send many comets into the inner Solar System, producing collisions with potentially catastrophic implications for life on Earth. The intense radiation of the galactic centre could also interfere with the development of complex life.[84] Even at the Solar System's current location, some scientists have hypothesised that recent supernovae may have adversely affected life in the last 35,000 years by flinging pieces of expelled stellar core towards the Sun in the form of radioactive dust grains and larger, comet-like bodies.[85] This article is about evolution in biology. ... This article is about life in general. ... For other uses, see Supernova (disambiguation). ...


Neighbourhood

Artist's conception of the Local Bubble
Artist's conception of the Local Bubble

The immediate galactic neighbourhood of the Solar System is known as the Local Interstellar Cloud or Local Fluff, an area of dense cloud in an otherwise sparse region known as the Local Bubble, an hourglass-shaped cavity in the interstellar medium roughly 300 light years across. The bubble is suffused with high-temperature plasma that suggests it is the product of several recent supernovae.[86] Image File history File links Local_bubble. ... Image File history File links Local_bubble. ... The Local Bubble is a cavity in the local interstellar medium (ISM) at least 300 light years across containing a neutral hydrogen density that is approximately one tenth of that of the average ISM in the Milky Way (approximately 0. ... The Local Interstellar Cloud is the interstellar cloud that our solar system is currently moving through. ... The Local Bubble is a cavity in the local interstellar medium (ISM) at least 300 light years across containing a neutral hydrogen density that is approximately one tenth of that of the average ISM in the Milky Way (approximately 0. ... The interstellar medium (or ISM) is the name astronomers give to the tenuous gas and dust that pervade interstellar space. ... Look up plasma in Wiktionary, the free dictionary. ...


The solar apex, the direction of the Sun's path through interstellar space, is near the constellation of Hercules in the direction of the current location of the bright star Vega.[87] The solar apex, or the Apex of the Suns Way, refers to the direction that the Sun travels through space. ... Hercules (IPA: ) is the fifth largest of the 88 modern constellations. ... For other uses, see Vega (disambiguation). ...


There are relatively few stars within ten light years (95 trillion km) of the Sun. The closest is the triple star system Alpha Centauri, which is about 4.4 light years away. Alpha Centauri A and B are a closely tied pair of Sun-like stars, while the small red dwarf Alpha Centauri C (also known as Proxima Centauri) orbits the pair at a distance of 0.2 light years. The stars next closest to the Sun are the red dwarfs Barnard's Star (at 5.9 light years), Wolf 359 (7.8 light years) and Lalande 21185 (8.3 light years). The largest star within ten light years is Sirius, a bright main sequence star roughly twice the Sun's mass and orbited by a white dwarf called Sirius B. It lies 8.6 light years away. The remaining systems within ten light years are the binary red dwarf system Luyten 726-8 (8.7 light years) and the solitary red dwarf Ross 154 (9.7 light years).[88] Our closest solitary sunlike star is Tau Ceti, which lies 11.9 light years away. It has roughly 80 percent the Sun's mass, but only 60 percent its luminosity.[89] The closest known estrasolar system to the Sun lies around the star Epsilon Eridani, a star slightly dimmer and redder than the Sun, which lies 10.5 light years away. Its one confirmed planet, Epsilon Eridani b, is roughly 1.5 times Jupiter's mass and orbits its star every 6.9 years.[90] This list of the nearest stars to Earth is ordered by increasing distance out to a maximum of 5 parsecs (16. ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ... Red dwarfs constitute the majority of all stars According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type. ... Proxima Centauri (Latin proximus, -a, -um: meaning next to or nearest to)[4] is a red dwarf star that is likely a part of the Alpha Centauri star system and is the nearest star to the Sun at a distance of 4. ... Barnards Star is a very low-mass star in the constellation Ophiuchus which was discovered by the astronomer E. E. Barnard in 1916. ... Wolf 359 is a star located approximately 2. ... Lalande 21185 is a red dwarf star approximately 2. ... For other uses, see Sirius (disambiguation). ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... This article or section does not adequately cite its references or sources. ... Luyten 726-8 is a binary star system that is one of Earths nearest neighbors. ... Ross 154 is a red dwarf star approximately 3. ... Tau Ceti (Ï„ Cet / Ï„ Ceti) is a star commonly mentioned by science fiction authors since it is similar to the Sun in mass and spectral type in addition to being relatively close to us. ... Epsilon Eridani (ε Eri / ε Eridani) is a notable main-sequence K2 class star in the constellation of Eridanus. ... Epsilon Eridani b is an extrasolar planet around Epsilon Eridani, announced in 2000 by a team led by Artie Hatzes. ...


Discovery and exploration

Main articles: Geocentric model and Heliocentrism

For many thousands of years, humanity, with a few notable exceptions, did not believe the Solar System existed. The Earth was believed not only to be stationary at the centre of the universe, but to be categorically different from the divine or ethereal objects that moved through the sky. While Nicolaus Copernicus and his predecessors, such as the Indian mathematician-astronomer Aryabhata and the Greek philosopher Aristarchus of Samos, had speculated on a heliocentric reordering of the cosmos, it was the conceptual advances of the 17th century, led by Galileo Galilei, Johannes Kepler, and Isaac Newton, which led gradually to the acceptance of the idea not only that Earth moved round the Sun, but that the planets were governed by the same physical laws that governed the Earth, and therefore could be material worlds in their own right, with such earthly phenomena as craters, weather, geology, seasons and ice caps. This article is about the historical term. ... Heliocentric Solar System Heliocentrism (lower panel) in comparison to the geocentric model (upper panel) In astronomy, heliocentrism is the theory that the sun is at the center of the Universe and/or the Solar System. ... For other uses, see Universe (disambiguation). ... Copernicus redirects here. ... For other uses, see Aryabhata (disambiguation). ... For other uses of this name, including the grammarian Aristarchus of Samothrace, see Aristarchus Statue of Aristarchus at Aristotle University in Thessalonica, Greece Aristarchus (Greek: Ἀρίσταρχος; 310 BC - ca. ... Galileo redirects here. ... Kepler redirects here. ... Sir Isaac Newton FRS (4 January 1643 – 31 March 1727) [ OS: 25 December 1642 – 20 March 1727][1] was an English physicist, mathematician, astronomer, natural philosopher, and alchemist. ...


Telescopic observations

A replica of Isaac Newton's telescope
A replica of Isaac Newton's telescope

The first exploration of the Solar System was conducted by telescope, when astronomers first began to map those objects too faint to be seen with the naked eye. Timeline of solar system astronomy // 2137 BC, October 22 - Chinese astronomers record a solar eclipse ca. ... Download high resolution version (1024x891, 118 KB)A replica of Isaac Newtons telescope of 1672. ... Download high resolution version (1024x891, 118 KB)A replica of Isaac Newtons telescope of 1672. ... This article does not cite any references or sources. ... For other uses, see Astronomy (disambiguation). ...


Galileo Galilei was the first to discover physical details about the individual bodies of the Solar System. He discovered that the Moon was cratered, that the Sun was marked with sunspots, and that Jupiter had four satellites in orbit around it.[91] Christiaan Huygens followed on from Galileo's discoveries by discovering Saturn's moon Titan and the shape of the rings of Saturn.[92] Giovanni Domenico Cassini later discovered four more moons of Saturn, the Cassini division in Saturn's rings, and the Great Red Spot of Jupiter.[93] Galileo redirects here. ... This article is about Earths moon. ... Christiaan Huygens (pronounced in English (IPA): ; in Dutch: ) (April 14, 1629 – July 8, 1698), was a Dutch mathematician, astronomer and physicist; born in The Hague as the son of Constantijn Huygens. ... Titan (, from Ancient Greek Τῑτάν) or Saturn VI is the largest moon of Saturn and the only moon known to have a dense atmosphere. ... The full set of rings, photographed as Saturn eclipsed the sun from the vantage of the Cassini spacecraft on September 15, 2006 (brightness has been exaggerated in this image). ... Giovanni Domenico (Jean-Dominique) Cassini Portrait Giovanni Domenico Cassini (June 8, 1625–September 14, 1712) was an Italian astronomer, engineer, and astrologer. ... Cassini Sidera Lodoicea (IPA ˈsɪdərə ˌlɒdəʊˈɪʃə) is the name given by the astronomer Giovanni Domenico Cassini to the four moons of Saturn discovered by him in the years 1671, 1672, and 1684 and published in the Journal des sçavans in 1673 and 1686. ... The full set of rings, photographed as Saturn eclipsed the sun from the vantage of the Cassini spacecraft on September 15, 2006 (brightness has been exaggerated in this image). ... A false-color image of the Great Red Spot of Jupiter from Voyager 1. ...


Edmond Halley realised in 1705 that repeated sightings of a comet were in fact recording the same object, returning regularly once every 75–76 years. This was the first evidence that anything other than the planets orbited the Sun.[94] Around this time (1704), the term "solar system" first appeared in English.[95] // Portrait of Edmond Halley painted around 1687 by Thomas Murray (Royal Society, London) Portrait of Edmond Halley Bust of Edmond Halley in the Museum of the Royal Greenwich Observatory Edmond Halley FRS (sometimes Edmund; IPA: ) (November 8, 1656 – January 14, 1742) was an English astronomer, geophysicist, mathematician, meteorologist, and physicist. ... This article is about the comet. ...


In 1781, William Herschel was looking for binary stars in the constellation of Taurus when he observed what he thought was a new comet. In fact, its orbit revealed that it was a new planet, Uranus, the first ever discovered.[96] For other persons named William Herschel, see William Herschel (disambiguation). ... For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... Taurus (IPA: , Latin: , symbol , ) is one of the constellations of the zodiac. ...


Giuseppe Piazzi discovered Ceres in 1801, a small world between Mars and Jupiter that was initially considered a new planet. However, subsequent discoveries of thousands of other small worlds in the same region led to their eventual reclassification as asteroids.[97] Giuseppe Piazzi. ... Spectral type: G[8] Absolute magnitude: 3. ... For other uses, see Asteroid (disambiguation). ...


By 1846, discrepancies in the orbit of Uranus led many to suspect a large planet must be tugging at it from farther out. Urbain Le Verrier's calculations eventually led to the discovery of Neptune.[98] The excess perihelion precession of Mercury's orbit led Le Verrier to postulate the intra-Mercurian planet Vulcan in 1859 – but that would turn out to be a red herring. Urbain Le Verrier. ... This article is about the planet. ... Vulcan was the name given to a small planet proposed to exist in an orbit between Mercury and the Sun in a 19th-century hypothesis. ...


While it is debatable when the Solar System was truly "discovered," two 19th century observations determined its nature and place in the universe beyond reasonable doubt. First, in 1838, Friedrich Wilhelm Bessel successfully measured a stellar parallax, an apparent shift in the position of a star created by the Earth's motion around the Sun. This was not only the first direct, experimental proof of heliocentrism, but also revealed, for the first time, the vast distance between our Solar System and the stars. Then, in 1856, Father Angelo Secchi, using the newly invented spectroscope, compared the spectral signature of the Sun with those of other stars, and found them virtually identical. The realisation that the Sun was a star led to the hypothesis that other stars could have systems of their own, though this was not to be proven for nearly 140 years. Friedrich Wilhelm Bessel (July 22, 1784 – March 17, 1846) was a German mathematician, astronomer, and systematizer of the Bessel functions (which, despite their name, were discovered by Daniel Bernoulli). ... Parallax (Greek: παραλλαγή = alteration) is the change of angular position of two stationary points relative to each other as seen by an observer, due to the motion of said observer. ... Pietro Angelo Secchi (June 18, 1818 – February 26, 1878) was an Italian astronomer. ... A spectroscope is a device which measures the spectrum of light. ...


Further apparent discrepancies in the orbits of the outer planets led Percival Lowell to conclude that yet another planet, "Planet X," must still be out there. After his death, his Lowell Observatory conducted a search which ultimately led to Clyde Tombaugh's discovery of Pluto in 1930. Pluto was, however, found to be too small to have disrupted the orbits of the outer planets, and its discovery was therefore coincidental. Like Ceres, it was initially considered to be a planet, but after the discovery of many other similarly sized objects in its vicinity it was reclassified in 2006 as a dwarf planet by the IAU.[98] Percival Lowell (March 13, 1855 – November 12, 1916) was an author, mathematician, and esteemed astronomer who fueled speculation that there were canals on Mars, founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the work and theories that led to the discovery of Pluto 14 years after... For other uses, see Planet X (disambiguation). ... Lowell Observatory Percival observing Mars from the Clark telescope at the Lowell Observatory. ... An image of Clyde Tombaugh Clyde William Tombaugh (February 4, 1906 – January 17, 1997) was an American astronomer who discovered the dwarf planet Pluto in 1930. ... For other uses, see Pluto (disambiguation). ... Artists impression of Pluto (background) and Charon (foreground). ...


In 1992, the first evidence of a planetary system other than our own was discovered, orbiting the pulsar PSR B1257+12. Three years later, 51 Pegasi b, the first extrasolar planet around a Sunlike star, was discovered. As of 2008, 221 extrasolar systems have been found.[99] An artists concept of a protoplanetary disc. ... It has been suggested that Radio pulsar be merged into this article or section. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... An extrasolar planet, or exoplanet, is a planet beyond the Solar System. ...


In 1992, astronomers David C. Jewitt of the University of Hawaii and Jane Luu of the Massachusetts Institute of Technology discovered (15760) 1992 QB1. This object proved to be the first of a new population, which came to be known as the Kuiper belt; an icy analogue to the asteroid belt of which such objects as Pluto and Charon were deemed a part.[100][101] David C. Jewitt is a Professor of astronomy at the University of Hawaii Institute for Astronomy. ... This article is about the University of Hawaii system. ... Dr. Jane Luu Dr. Jane Luu (a. ... “MIT” redirects here. ... (15760) 1992 QB1 (also written (15760) 1992 QB1) was the first trans-Neptunian object to be discovered after Pluto and Charon. ... The Kuiper belt, derived from data from the Minor Planet Center. ...


Mike Brown, Chad Trujillo and David Rabinowitz announced the discovery of Eris in 2005, a scattered disc object larger than Pluto and the largest object discovered in orbit round the Sun since Neptune.[102] Michael (Mike) E. Brown (born c. ... Chadwick A. Chad Trujillo (born November 22, 1973), is the co-discoverer of Eris, which he claims to be the Tenth Planet. ... This article or section does not cite its references or sources. ... Absolute magnitude: −1. ... Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ...


Observations by spacecraft

Artist's conception of Pioneer 10, which passed the orbit of Pluto in 1983. The last transmission was received in January 2003, sent from approximately 82 AU away. The 35-year-old space probe is now receding at over 43,400 km/h (27,000 mph) from the Sun.
Artist's conception of Pioneer 10, which passed the orbit of Pluto in 1983. The last transmission was received in January 2003, sent from approximately 82 AU away. The 35-year-old space probe is now receding at over 43,400 km/h (27,000 mph) from the Sun.[103]

Since the start of the Space Age, a great deal of exploration has been performed by robotic spacecraft missions that have been organized and executed by various space agencies. Timeline of solar system exploration organized by date of launch. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Pioneer 10 was the first spacecraft to travel through the asteroid belt, and was the first spacecraft to make direct observations of Jupiter. ... The Space Shuttle takes off on a manned mission to space. ... An artists interpretation of the MESSENGER spacecraft at Mercury A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. ...


All planets in the Solar System have now been visited to varying degrees by spacecraft launched from Earth. Through these unmanned missions, humans have been able to get close-up photographs of all of the planets and, in the case of landers, perform tests of the soils and atmospheres of some. A lander is a type of spacecraft which descends to come to rest on the surface of an astronomical body. ... For other uses, see Atmosphere (disambiguation). ...


The first manmade object sent into space was the Soviet satellite Sputnik 1, launched in 1957, which successfully orbited the Earth for over a year. The American probe Explorer 6, launched in 1959, was the first satellite to image the Earth from space. Sputnik 1 (Russian: , Satellite-1, or literally Co-traveler-1 byname ПС-1 (PS-1, i. ... Explorer 6 was a US satellite launched on August 7, 1959. ...


Flybys

The first successful probe to fly by another Solar System body was Luna 1, which sped past the Moon in 1959. Originally meant to impact with the Moon, it instead missed its target and became the first manmade object to orbit the Sun. Mariner 2 was the first probe to fly by another planet, Venus, in 1962. The first successful flyby of Mars was made by Mariner 4 in 1965. Mercury was first encountered by Mariner 10 in 1974. Luna 1 is the first spacecraft to reach the vicinity of the Moon and the first of the Luna programme of Soviet automatic interplanetary stations successfully launched in the direction of the Moon. ... -1... Mariner 4 (Mariner-Mars 1964) was the fourth in a series of spacecraft used for planetary exploration in a flyby mode and performed the first successful flyby of the planet Mars, returning the first pictures of the Martian surface. ... This article is about the planet. ... The Mariner 10 probe. ...

A photo of Earth (circled) taken by Voyager 1, 6.4 billion km (4 billion miles) away. The streaks of light are diffraction spikes radiating from the Sun (off frame to the left). This photograph is known as Pale Blue Dot
A photo of Earth (circled) taken by Voyager 1, 6.4 billion km (4 billion miles) away. The streaks of light are diffraction spikes radiating from the Sun (off frame to the left). This photograph is known as Pale Blue Dot

The first probe to explore the outer planets was Pioneer 10, which flew by Jupiter in 1973. Pioneer 11 was the first to visit Saturn, in 1979. The Voyager probes performed a grand tour of the outer planets following their launch in 1977, with both probes passing Jupiter in 1979 and Saturn in 1980 – 1981. Voyager 2 then went on to make close approaches to Uranus in 1986 and Neptune in 1989. The Voyager probes are now far beyond Neptune's orbit, and are on course to find and study the termination shock, heliosheath, and heliopause. According to NASA, both Voyager probes have encountered the termination shock at a distance of approximately 93 AU from the Sun.[70][104] This is the Pale Blue Dot photograph of the Earth taken by the Voyager 1 spacecraft. ... This is the Pale Blue Dot photograph of the Earth taken by the Voyager 1 spacecraft. ... Seen from four billion miles away, Earth is a dot obscured in a beam of scattered sunlight (pinpointed by artificial blue circle). ... For the album by The Verve, see Voyager 1 (album). ... Seen from four billion miles away, Earth is a dot obscured in a beam of scattered sunlight (pinpointed by artificial blue circle). ... Pioneer 10 was the first spacecraft to travel through the asteroid belt, and was the first spacecraft to make direct observations of Jupiter. ... Position of Pioneer 10 and 11 Pioneer 11 was the second mission to investigate Jupiter and the outer solar system and the first to explore the planet Saturn and its main rings. ... Voyager Project redirects here. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... The locations of Voyagers 1 and 2 as of 2005 In space physics, the termination shock is the boundary marking one of the outer limits of the suns influence. ... The National Aeronautics and Space Administration (NASA) (IPA [ˈnæsÉ™]) is an agency of the United States government, responsible for the nations public space program. ...


The first flyby of a comet occurred in 1985, when the International Cometary Explorer (ICE) passed by the comet Giacobini-Zinner,[105] while the first flybys of asteroids were conducted by the Galileo spaceprobe, which imaged both 951 Gaspra (in 1991) and 243 Ida (in 1993) on its way to Jupiter. The International Cometary Explorer (ICE) spacecraft was originally known as International Sun/Earth Explorer 3 (ISEE-3) satellite, launched August 12, 1978. ... Comet Giacobini-Zinner was discovered by Michel Giacobini (Nice, France) in Aquarius on December 20, 1900. ... Galileo is prepared for mating with the IUS booster Galileo and Inertial Upper Stage being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ... 951 Gaspra is an S-type asteroid that orbits very close to the inner edge of the asteroid belt. ... NASA image of 243 Ida. ... For other uses, see Jupiter (disambiguation). ...


No Kuiper belt object has yet been visited by a spacecraft. Launched on January 19, 2006, the New Horizons probe is currently en route to becoming the first man-made spacecraft to explore this area. This unmanned mission is scheduled to fly by Pluto in July 2015. Should it prove feasible, the mission will then be extended to observe a number of other Kuiper belt objects.[106] is the 19th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... New Horizons on the launchpad New Horizons is a robotic spacecraft mission conducted by NASA. It is expected to be the first spacecraft to fly by and study the dwarf planet Pluto and its moons, Charon, Nix and Hydra. ...


Orbiters, landers and rovers

In 1966, the Moon became the first Solar System body beyond Earth to be orbited by an artificial satellite (Luna 10), followed by Mars in 1971 (Mariner 9), Venus in 1975 (Venera 9), Jupiter in 1995 (Galileo), the asteroid 433 Eros in 2000 (NEAR Shoemaker), and Saturn in 2004 (Cassini–Huygens). The MESSENGER probe is currently en route to commence the first orbit of Mercury in 2011, while the Dawn spacecraft is currently set to orbit the asteroid Vesta in 2011 and the dwarf planet Ceres in 2015. For other uses, see Satellite (disambiguation). ... Luna 10 was an unmanned space mission of the Luna program, also called Lunik 10. ... Mariner 9 launch Mariner 9 (Mariner Mars 71 / Mariner-I) was a NASA space probe orbiter that helped in the exploration of Mars and was part of the Mariner program. ... Venera 9 (Russian: Венера-9) was a USSR unmanned space mission to Venus. ... Galileo is prepared for mating with the IUS booster Galileo and Inertial Upper Stage being deployed after being launched by the Space Shuttle Atlantis on the STS-34 mission Galileo was an unmanned spacecraft sent by NASA to study the planet Jupiter and its moons. ... The asteroid 433 Eros (eer-os) was named after the Greek god of love Eros. ... Artists conception of the NEAR Shoemaker spacecraft Near Earth Asteroid Eros as seen from the NEAR spacecraft. ... Cassini–Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ... This article is about the NASA space mission. ... The Dawn Mission, launched on September 27, 2007, is NASAs mission to send a robotic space probe to the two most massive members of the asteroid belt: the asteroid Vesta and the dwarf planet Ceres. ... 4 Vesta (ves-ta) is the second most massive asteroid in the asteroid belt, with a mean diameter of about 530 km and an estimated mass 12% the mass of the entire asteroid belt. ... Spectral type: G[8] Absolute magnitude: 3. ...


The first probe to land on another Solar System body was the Soviet Luna 2 probe, which impacted the Moon in 1959. Since then, increasingly distant planets have been reached, with probes landing on or impacting the surfaces of Venus in 1966 (Venera 3), Mars in 1971 (Mars 3, although a fully successful landing didn't occur until Viking 1 in 1976), the asteroid 433 Eros in 2001 (NEAR Shoemaker), and Saturn's moon Titan (Huygens) and the comet Tempel 1 (Deep Impact) in 2005. The Galileo orbiter also dropped a probe into Jupiter's atmosphere in 1995; since Jupiter has no physical surface, it was destroyed by increasing temperature and pressure as it descended. This is a list of all spacecraft landings on other planets and bodies in the solar system, including both intended and unintended crash-landings. ... Soviet Soyuz rockets like the one pictured above were the first reliable means to transport objects into Earth orbit. ... Luna 2 (E-1A series) was the second of the Soviet Unions Luna program spacecraft launched in the direction of the Moon. ... Venera 3 Venera-3 on-board medal Venera 3 (Russian:Венера-3) was a Venera program space probe that was built and launched by the Soviet Union to explore the surface of Venus. ... It has been suggested that this article or section be merged with Mars 2. ... Viking 1 was the first of two spacecraft sent to Mars as part of NASAs Viking program, and holds the record for the longest Mars surface mission. ... The asteroid 433 Eros (eer-os) was named after the Greek god of love Eros. ... Artists conception of the NEAR Shoemaker spacecraft Near Earth Asteroid Eros as seen from the NEAR spacecraft. ... Titan (, from Ancient Greek Τῑτάν) or Saturn VI is the largest moon of Saturn and the only moon known to have a dense atmosphere. ... The Huygens probe, supplied by the European Space Agency (ESA) and named after the Dutch 17th century astronomer Christiaan Huygens, is an atmospheric entry probe carried to Saturns moon Titan as part of the Cassini-Huygens mission. ... Tempel 1 is a periodic comet (formally designated 9P/Tempel 1). ... Illustration of the Deep Impact space probe after impactor separation (artists conception) Deep Impact is a NASA space probe designed to study the composition of the interior of the comet Tempel 1. ...


To date, only two worlds in the Solar System, the Moon and Mars, have been visited by mobile rovers. The first rover to visit another celestial body was the Soviet Lunokhod 1, which landed on the Moon in 1970. The first to visit another planet was Sojourner, which travelled 500 metres across the surface of Mars in 1997. The only manned rover to visit another world was NASA's Lunar rover, which travelled with Apollos 15, 16 and 17 between 1971 and 1972. Two different Mars rover designs. ... Lunokhod series Soviet Moon exploration robot vehicle A panorama shot from Lunokhod 1 A photo from Lunokhod 1 showing the Luna 17 lander The tracks of Lunokhod showing the little wheel in the center that was used for odometry. ... Sojourner next to the rock Barnacle Bill The Sojourner rover was the first space exploration rover to successfully reach another planet. ... For the Soviet robotic rovers, see Lunokhod programme. ... Apollo 15 was the ninth manned mission in the Apollo program and the fourth mission to land on the Moon. ... Apollo 16 was the tenth manned mission in the Apollo program and the fifth mission to land on the Moon. ... Apollo 17 was the eleventh manned space mission in the NASA Apollo program. ...


Manned exploration

Manned exploration of the Solar System is currently confined to Earth's immediate environs. The first human being to reach space (defined as an altitude of over 100 km) and to orbit the Earth was Yuri Gagarin, a Soviet cosmonaut who was launched in Vostok 1 on April 12, 1961. The first man to walk on the surface of another Solar System body was Neil Armstrong, who stepped onto the Moon on July 21, 1969 during the Apollo 11 mission; five more Moon landings occurred through 1972. The United States' Space Shuttle, which debuted in 1981, is the only reusable spacecraft to successfully make multiple orbital flights. The five shuttles that have been built have flown a total of 121 missions, with two of the craft destroyed in accidents. The first orbital space station to host more than one crew was NASA's Skylab, which successfully held three crews from 1973 to 1974. The first true human settlement in space was the Soviet space station Mir, which was continuously occupied for close to ten years, from 1989 to 1999. It was decommissioned in 2001, and its successor, the International Space Station, has maintained a continuous human presence in space since then. In 2004, SpaceShipOne became the first privately funded vehicle to reach space on a suborbital flight. That same year, U.S. President George W. Bush announced the Vision for Space Exploration, which called for a replacement for the aging Shuttle, a return to the Moon and, ultimately, a manned mission to Mars. Layers of Atmosphere - not to scale (NOAA)[1] Atmospheric gases scatter blue wavelengths of visible light more than other wavelengths, giving the Earth’s visible edge a blue halo. ... “Gagarin” redirects here. ... Soviet redirects here. ... U.S. Space Shuttle astronaut Bruce McCandless II using a manned maneuvering unit. ... Vostok 1 (Russian: , meaning Orient-1 or East-1) was the first human spaceflight. ... is the 102nd day of the year (103rd in leap years) in the Gregorian calendar. ... Year 1961 (MCMLXI) was a common year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... This article is about the former American astronaut. ... This article is about Earths moon. ... is the 202nd day of the year (203rd in leap years) in the Gregorian calendar. ... Also: 1969 (number) 1969 (movie) 1969 (Stargate SG-1) episode. ... This article covers the Apollo 11 mission itself. ... Year 1972 (MCMLXXII) was a leap year starting on Saturday (link will display full calendar) of the Gregorian calendar. ... This article is about the space vehicle. ... Year 1981 (MCMLXXXI) was a common year starting on Thursday (link displays the 1981 Gregorian calendar). ... The International Space Station in 2007 A space station is an artificial structure designed for humans to live in outer space. ... The National Aeronautics and Space Administration (NASA) (IPA [ˈnæsə]) is an agency of the United States government, responsible for the nations public space program. ... For other uses, see Skylab (disambiguation). ... For other uses, see Mir (disambiguation). ... ISS redirects here. ... SpaceShipOne is small, having a three-person cabin and short but wide wings. ... George Walker Bush (born July 6, 1946) is the forty-third and current President of the United States of America, originally inaugurated on January 20, 2001. ... Image from NASA site Two planned configurations for a return to the moon, heavy lift (left) and crew (right) The Vision for Space Exploration is the United States space policy announced on January 14, 2004 by President George W. Bush. ...


See also

Solar System Portal

Image File history File links Download high resolution version (1024x1274, 113 KB) Original caption released with image This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars... Below is a list of solar system objects with diameter >500km: The Sun, a spectral class G2 star Mercury Venus Earth Moon Mars Jupiter Io Europa Ganymede Callisto complete list of Jupiters natural satellites Saturn Tethys Dione Rhea Titan Iapetus complete list of Saturns natural satellites Uranus Ariel... This is a list of solar system objects by mass, in decreasing order. ... It has been suggested that Planetary-size comparison be merged into this article or section. ... This is a list of named solar system objects, including planets, moons, dwarf planets, and trans-Neptunian objects, ordered alphabetically. ... The following values were calculated using Newtons law of universal gravitation. ... These tables list the atributes of the solar systems largest objects (excluding the Sun). ... Chinese Celestial symbols on an antique bronze mirror Astronomical symbols are symbols used to represent various celestial objects, theoretical constructs and observational events in astronomy. ... This is a directory of lists of geological features on other planets, moons and asteroids. ... A Solar System Numerical Model A Law of Motion for Entities in a Solar System Numerical Model The solar system may be modeled numerically using both Newtons Law of Gravitation and Newtons Second Law of Motion. ... Overview of the planets and dwarf planets in the Solar System. ... This timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. ... Jupiter at South Station, part of Museum of Science, Boston scale model. ... Artists conception of a space habitat called the Stanford torus, by Don Davis Space colonization (also called space settlement, space humanization, space habitation, etc. ... The Solar system and its various bodies (planets, asteroids, moons, etc. ... For other uses, see Celestia (disambiguation). ... The family portrait taken by Voyager 1 The Family Portrait, or Portrait of the Planets is an image of the Solar System created by Voyager 1 on February 14, 1990; the last taken by the spacecraft before it began its mission into interstellar space. ... Isaac Newton, one of the greatest scientists of all time, was also a devout Christian. ...

Notes

  1. ^ Capitalization of the name varies. The IAU, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects (Solar System). However, the name is commonly rendered in lower case (solar system) including in the Oxford English Dictionary, Merriam-Webster's 11th Collegiate Dictionary, and Encyclopædia Britannica.
  2. ^ The mass of the Solar System excluding the Sun, Jupiter and Saturn can be determined by adding together all the calculated masses for its largest objects and using rough calculations for the masses of the Oort cloud (estimated at roughly 3 Earth masses),[107] the Kuiper Belt (estimated at roughly 0.1 Earth mass)[64] and the asteroid belt (estimated to be 0.0005 Earth mass)[48] for a total, rounded upwards, of ~37 Earth masses, or 8.9 percent the combined mass of Jupiter and Saturn.

Capitalization (or capitalisation) is writing a word with its first letter as a majuscule (upper case letter) and the remaining letters in minuscules (lower case letters), in those writing systems which have a case distinction. ... IAU redirects here. ... The Oxford English Dictionary print set The Oxford English Dictionary (OED) is a dictionary published by the Oxford University Press (OUP), and is the most successful dictionary of the English language, (not to be confused with the one-volume Oxford Dictionary of English, formerly New Oxford Dictionary of English, of...

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Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 204th day of the year (205th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 214th day of the year (215th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... This article is about the day. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 61st day of the year (62nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 46th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 203rd day of the year (204th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... December 27 is the 361st day of the year in the Gregorian calendar (362nd in leap years). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 11th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 46th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... “PDF” redirects here. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 9th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2000 (MM) was a leap year starting on Saturday (link will display full 2000 Gregorian calendar). ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 19th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 320th day of the year (321st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 122nd day of the year (123rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 320th day of the year (321st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 323rd day of the year (324th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 320th day of the year (321st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... “PDF” redirects here. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 42nd day of the year in the Gregorian calendar. ... “PDF” redirects here. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 323rd day of the year (324th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 302nd day of the year (303rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 363rd day of the year (364th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 341st day of the year (342nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... is the 68th day of the year (69th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 204th day of the year (205th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 197th day of the year (198th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 276th day of the year (277th in leap years) in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... is the 46th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 35th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 173rd day of the year (174th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 42nd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 34th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 34th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 40th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 257th day of the year (258th in leap years) in the Gregorian calendar. ... “PDF” redirects here. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 323rd day of the year (324th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 204th day of the year (205th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Georgij A. Krasinsky is a Russian astronomer active at the Institute of Applied Astronomy, Russian Academy of Science, St Petersburg. ... Elena Vladimirovna Pitjeva is a Russian theoretical physicist at the Institute of Applied Astronomy, Russian Academy of Sciences, St. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 243rd day of the year (244th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 241st day of the year (242nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 16th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 2nd day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 104th day of the year (105th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 3rd day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 250th day of the year (251st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 236th day of the year (237th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 360th day of the year (361st in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 197th day of the year (198th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 258th day of the year (259th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 5th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 36th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 323rd day of the year (324th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 122nd day of the year (123rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 204th day of the year (205th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 204th day of the year (205th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 204th day of the year (205th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 174th day of the year (175th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 33rd day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 204th day of the year (205th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 43rd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... December 27 is the 361st day of the year in the Gregorian calendar (362nd in leap years). ... 2008 (MMVIII) will be a leap year starting on Tuesday of the Anno Domini (common) era, in accordance with the Gregorian calendar. ... is the 24th day of the year in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... is the 1st day of the year in the Gregorian calendar. ... The Union Jack, flag of the newly formed United Kingdom of Great Britain and Ireland. ... is the 1st day of the year in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 312th day of the year (313th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) will be a leap year starting on Tuesday of the Anno Domini (common) era, in accordance with the Gregorian calendar. ... is the 24th day of the year in the Gregorian calendar. ... “MIT” redirects here. ... This article is about the University of Hawaii system. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 313th day of the year (314th in leap years) in the Gregorian calendar. ... The Minor Planet Center operates at the Smithsonian Astrophysical Observatory (SAO), which is part of the Center for Astrophysics (CfA) along with the Harvard College Observatory (HCO). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 313th day of the year (314th in leap years) in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... is the 56th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 192nd day of the year (193rd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 296th day of the year (297th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 215th day of the year (216th in leap years) in the Gregorian calendar. ...

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The Solar System
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The Sun Mercury Venus The Moon Earth Phobos and Deimos Mars Ceres The asteroid belt Jupiter Jupiter's natural satellites Saturn Saturn's natural satellites Uranus Uranus' natural satellites Neptune's natural satellites Neptune Charon, Nix, and Hydra Pluto The Kuiper belt Dysnomia Eris The scattered disc The Oort cloud
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(minor planets)
Groups and families: Vulcanoids · Near-Earth asteroids · Asteroid belt
Jupiter Trojans · Centaurs · Neptune Trojans · Asteroid moons · Meteoroids
See also the list of asteroids, and the meaning and pronunciation of asteroid names.
Trans-
Neptunians
Kuiper beltPlutinos: Orcus · IxionCubewanos: 2002 UX25 · Varuna ·
1992 QB1 · 2002 TX300 · 2003 EL61 · Quaoar · 2005 FY9 · 2002 AW197
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Comets Lists of periodic and non-periodic comets · Damocloids · Oort cloud
See also Geology of solar terrestrial planets, astronomical objects, the solar system's list of objects, sorted by radius or mass, and the Solar System Portal

Image File history File links Commons-logo. ... Wikipedia does not have an article with this exact name. ... Image File history File links Wikibooks-logo. ... Image File history File links Wikiquote-logo. ... Image File history File links Wikisource-logo. ... Image File history File links Commons-logo. ... Image File history File links WikiNews-Logo. ... Image File history File links Wikiversity-logo-Snorky. ... A small orrery showing earth and the inner planets An orrery is a mechanical device that illustrates the relative positions and motions of the planets and moons in the solar system in heliocentric model. ... Sol redirects here. ... The heliosphere is a bubble in space produced by the solar wind. ... This article is about the astronomical term. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... This article is about the planet. ... For other uses, see Venus (disambiguation). ... This article is about Earth as a planet. ... This article is about Earths moon. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale. ... For other uses, see Jupiter (disambiguation). ... Jupiters outer moons and their highly inclined orbits. ... A schema of Jupiters ring system showing the four main components The rings of Jupiter are a system of planetary rings around the planet Jupiter. ... This article is about the planet. ... The Saturnian system (photographic montage) Saturn has 60 confirmed natural satellites, plus three hypothetical moons. ... The full set of rings, photographed as Saturn eclipsed the sun from the vantage of the Cassini spacecraft on September 15, 2006 (brightness has been exaggerated in this image). ... For other uses, see Uranus (disambiguation). ... Uranus has 27 known moons. ... This is a list of the named planetary rings of Uranus. ... For other uses, see Neptune (disambiguation). ... Neptune (top) and Triton (bottom), 3 days after the Voyager 2 flyby. ... This is a list of the named rings and ring arcs of Neptune. ... Artists impression of Pluto (background) and Charon (foreground). ... Spectral type: G[8] Absolute magnitude: 3. ... For other uses, see Pluto (disambiguation). ... The planet Pluto has three known moons. ... Absolute magnitude: −1. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... It has been suggested that minor planet be merged into this article or section. ... For other uses, see Asteroid (disambiguation). ... Minor planet is the official term for asteroids and trans-Neptunian objects. ... Vulcanoids are hypothetical asteroids that may orbit in a dynamically stable zone between 0. ... Computer model of the Apollo Asteroid 6489 Golevka Near-Earth asteroids (NEAs) are asteroids whose orbits are close to Earths orbit. ... For other uses, see Asteroid (disambiguation). ... Image of the Trojan asteroids in front of and behind Jupiter along its orbital path. ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... As of March 2007, there are five[1] known Neptune Trojans (named by analogy to the Trojan asteroids) which have the same orbital period as the planet. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... Worlds second largest Meteorite in Culiacan, Mexico A meteorite is a relatively small extra-terrestrial body that reaches the Earths surface. ... This is a list of numbered minor planets, nearly all of them asteroids, in sequential order. ... This is a list of named asteroids, with links to the Wikipedia articles on the people, places, characters and concepts that they are named after. ... This page alphabetically lists the first thousand asteroids to be numbered, which are mostly in the main belt. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... The Kuiper belt, derived from data from the Minor Planet Center. ... In astronomy, a plutino is a trans-Neptunian object that has a 3:2 orbital resonance with Neptune. ... 90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. ... 28978 Ixion (IPA pronunciation: , Wiktionary:Ixion) is a Kuiper belt object discovered on May 22, 2001. ... A cubewano is any substantial Kuiper belt object, orbiting beyond about 41 AU and not controlled by resonances with the outer planets. ... The correct title of this article is (55637) 2002 UX25. ... 20000 Varuna (VAR oo na) is a large classical Kuiper Belt object (KBO). ... (15760) 1992 QB1 (also written (15760) 1992 QB1) was the first trans-Neptunian object to be discovered after Pluto and Charon. ... (55636) 2002 TX300 (Also written as (55636) 2002 TX300) is a large Trans-Neptunian object discovered in October 15, 2002 by the NEAT program. ... (also written (136108) 2003 EL61), nicknamed Easter Bunny, is a large Kuiper belt object, roughly one-third the mass of Pluto, discovered by J. L. Ortiz et al. ... 50000 Quaoar (pronounced kwaa·waar or kwow·ər, English IPA: , Tongva ) [2] is a Trans-Neptunian object orbiting the Sun in the Kuiper belt. ... (also written (136472) 2005 FY9) is a very large Kuiper belt object, and one of the two largest among the population in the classical KBO orbits. ... is a trans-Neptunian object (TNO). ... Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ... (84522) 2002TC302 is a large Scattered Disk Object (SDO), orbiting the sun at a distance of 39. ... 2004 XR190 (also written 2004 XR190) is a newly discovered trans-Neptunian object located in the scattered disc. ... you are abunch of bull | bgcolour=#FFFFC0 | name=90377 Sedna | image= | caption= Sedna is located in the center of the green circle | discovery=yes | discoverer=M. Brown, C. Trujillo, D. Rabinowitz | discovered=November 14, 2003 | mp_name=90377 Sedna | alt_names= | mp_category=Trans-Neptunian object | epoch=September 26, 1990 (JD 2448160. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... The following is the IAUs list of periodic comets that have a number designation. ... Non-periodic comets are seen on only one occasion. ... Damocloids are asteroids such as 5335 Damocles and (16746) 1996 PW that have long-period highly eccentric orbits typical of periodic comets such as 1P/Halley, but without showing a cometary coma or tail. ... Artists rendering of the Oort cloud and the Kuiper Belt. ... The inner planets. ... Astronomical objects are significant physical entities, associations or structures which current science has confirmed to exist in space. ... Below is a list of solar system objects with diameter >500km: The Sun, a spectral class G2 star Mercury Venus Earth Moon Mars Jupiter Io Europa Ganymede Callisto complete list of Jupiters natural satellites Saturn Tethys Dione Rhea Titan Iapetus complete list of Saturns natural satellites Uranus Ariel... It has been suggested that Planetary-size comparison be merged into this article or section. ... This is a list of solar system objects by mass, in decreasing order. ... This article is about Earth as a planet. ... Layers of Atmosphere - not to scale (NOAA)[1] Outer space, sometimes simply called space, refers to the relatively empty regions of the universe outside the atmospheres of celestial bodies. ... This article is about Earth as a planet. ... The Local Interstellar Cloud is the interstellar cloud that our solar system is currently moving through. ... The Local Bubble is a cavity in the local interstellar medium (ISM) at least 300 light years across containing a neutral hydrogen density that is approximately one tenth of that of the average ISM in the Milky Way (approximately 0. ... Observed structure of the Milky Ways spiral arms The Orion Arm or Local Arm (labeled 0) is a minor, spiral arm of the Milky Way galaxy. ... For other uses, see Milky Way (disambiguation). ... A member of the Local Group of galaxies, irregular galaxy Sextans A is 4. ... The Virgo Supercluster The Virgo Supercluster or Local Supercluster is the galactic supercluster that contains the Local Group, the latter which, in its turn, contains the Milky Way and Andromeda galaxies. ... See universe for a general discussion of the universe. ... For other uses, see Universe (disambiguation). ... For other uses, see System (disambiguation). ... Systems science is the science of complex systems. ... An example of a system: The nervous system. ... There are many definitions of complexity, therefore many natural, artificial and abstract objects or networks can be considered to be complex systems, and their study (complexity science) is highly interdisciplinary. ... Complex adaptive systems are special cases of complex systems. ... A conceptual system is a system that is comprised of non-physical objects, i. ... Cultural system refers to the functional interaction between the different elements of culture in a particular manner. ... The Lorenz attractor is an example of a non-linear dynamical system. ... An economic system is a particular set of social institutions which deals with the production, distribution and consumption of goods and services in a particular society. ... A coral reef near the Hawaiian islands is an example of a complex marine ecosystem. ... In logic and mathematics, a formal system consists of two components, a formal language plus a set of inference rules or transformation rules. ... GPS redirects here. ... List of bones of the human skeleton Human anatomy is primarily the scientific study of the morphology of the adult human body. ... Information System (example) An Information System (IS) is the system of persons, data records and activities that process the data and information in a given organization, including manual processes or automated processes. ... World distribution of major legal traditions The three major legal systems of the world today consist of civil law, common law and religious law. ... A system of measurement is a set of units which can be used to specify anything which can be measured and were historically important, regulated and defined because of trade and internal commerce. ... The International System of Units (symbol: SI) (for the French phrase Syst me International dUnit s) is the most widely used system of units. ... The nervous system is a highly specialized network whose principal components are cells called neurons. ... In mathematics, a nonlinear system is one whose behavior cant be expressed as a sum of the behaviors of its parts (or of their multiples. ... An operating system (OS) is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. ... A physical system is a system that is comprised of matter and energy. ... A political system is a system of politics and government. ... The human eye is the first element of a sensory system: in this case, vision, for the visual system. ... See Social structure of the United States for an explanation of concepts exsistance within US society. ... For other uses, see Chaos Theory (disambiguation). ... Complex systems have a number of properties, some of which are listed below. ... For control theory in psychology and sociology, see control theory (sociology). ... For other uses, see Cybernetics (disambiguation). ... Holism in science, or Holistic science, is an approach to research that emphasizes the study of complex systems. ... Sociotechnical systems theory is theory about the social aspects of people and society and technical aspects of machines and technology. ... Systems biology is a term used very widely in the biosciences, particularly from the year 2000 onwards, and in a variety of contexts. ... System dynamics is an approach to understanding the behaviour of complex systems over time. ... Systems Ecology is a transdiscipline which studies ecological systems, or ecosystems. ... Systems engineering techniques are used in complex projects: from spacecrafts to chip design, from robotics to creating large software products to building bridges, Systems engineering uses a host of tools that include modeling & simulation, requirements analysis, and scheduling to manage complexity Systems Engineering (SE) is an interdisciplinary approach and means... Systems science is the science of complex systems. ... Systems theory is an interdisciplinary field of science. ... Russell Lincoln Ackoff (born 12 February 1919) is a Professor Emeritus of the Wharton School in operations research and systems theory. ... William Ross Ashby (September 6, 1903, London, England - November 15, 1972) was a British psychiatrist and a pioneer in the study of complex systems. ... Gregory Bateson (9 May 1904–4 July 1980) was a British anthropologist, social scientist, linguist and cyberneticist whose work intersected that of many other fields. ... Anthony Stafford Beer (September 25, 1926 - August 23, 2002) was a theorist in operational research and management cybernetics. ... Karl Ludwig von Bertalanffy (September 19, 1901, Vienna, Austria - June 12, 1972, New York, USA) was a biologist who was a founder of general systems theory--which he literally translated from the mathematization of Nicolai Hartmanns Ontology as stated by himself in his seminal work-- .An Austrian citizen, he... Kenneth E. Boulding Kenneth Ewart Boulding (January 18, 1910 - March 18, 1993) was an economist, educator, peace activist, poet, religious mystic, devoted Quaker, systems scientist, and interdisciplinary philosopher. ... British academic Peter Checkland is the developer of soft-systems methodology (SSM) in the field of systems thinking. ... Charles West Churchman (born August 29, 1913 Philadelphia, Pennsylvania, died March 21, 2004 Bolinas, California) was an American philospher in the field of management science, operations research and systems theory. ... He is a twat He was born in Vienna and died in Pescadero, California. ... Charles François is a Belgian citizen, born 1922 and retired from the Belgian Foreign Service since 1987. ... Jay Wright Forrester (born 14 July 1918 Climax, Nebraska) is an American pioneer of computer engineering. ... Ralph Waldo Gerard (7 October 1900, Harvey, Illinois - 17 February 1974) was an American neurophysiologist and behavioral scientist known for his wide-ranging work on the nervous system, nerve metabolism, psychopharmacology, and biological bases of schizophrenia [1]. // Gerard was born in Harvey, Illinois at the beginning of the 20th century. ... Debora Hammond down the Green River in Canyonlands National Park Debora Hammond is an American systems theorist, working as an Associate Professor professor Interdisciplinary Studies of the Hutchins School of Liberal Studies at the Sonoma State University. ... George Jiri Klir (1932 Prague, Czechoslovakia) is an Czech-American computer scientist and professor of systems sciences at the Center for Intelligent Systems at the Binghamton University in New York. ... Niklas Luhmann (December 8, 1927 - November 6, 1998) was a German sociologist, administration expert, and social systems theorist, as well as one the most prominent modern day thinkers in the sociological systems theory. ... Humberto Maturana (born September 14, 1928 in Santiago) is a Chilean biologist whose work crosses over into philosophy and cognitive science. ... Donella Dana Meadows (March 13, 1941 Elgin, Illinois, USA - February 20, 2001, New Hampshire) was a pioneering environmental scientist, a teacher and writer. ... Mihajlo D. Mesarovic (1928) is a Yugoslavian scientist, who was professor of Systems Engineering and Mathematics at Case Western Reserve University. ... Howard Thomas Odum (1924-2002), commonly known as H.T. Odum or Tom Odum, was an eminent American ecosystem ecologist and a professor at the University of Florida. ... Talcott Parsons Talcott Edgar Frederick Parsons (December 13, 1902–May 8, 1979) was for many years the best-known sociologist in the United States, and indeed one of the best-known in the world. ... Ilya Prigogine (January 25, 1917 – May 28, 2003) was a Belgian physicist and chemist noted for his work on dissipative structures, complex systems, and irreversibility. ... Anatol Rapoport (born May 22, 1911) is a Russian-born American Jewish, mathematical psychologist. ... Francisco Varela (Santiago, September 7, 1946 – May 28, 2001, Paris) was a Chilean biologist and philosopher who, together with his teacher Humberto Maturana, is best known for introducing the concept of autopoiesis to biology. ... JOHN N. WARFIELD The career of John Warfield has been described as passing through four phases: Phase 1: Electrical engineering faculty member: 1948-1965 Phase 2: Starting a systems science research career path: 1966-1980 Phase 3: Accruing evidence and developing components of systems science: 1980-2000 Phase 4: Aggregating... Norbert Wiener Norbert Wiener (November 26, 1894, Columbia, Missouri – March 18, 1964, Stockholm Sweden) was an American theoretical and applied mathematician. ...


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The Solar System (1562 words)
Nearly all the solar system by volume appears to be an empty void.
The solar magnetic field is the dominating magnetic field throughout the interplanetary regions of the solar system, except in the immediate environment of planets which have their own magnetic fields.
The terrestrial planets are the four innermost planets in the solar system, Mercury, Venus, Earth and Mars.
Solar System - MSN Encarta (1887 words)
Solar System, the Sun and everything that orbits the Sun, including the nine planets and their satellites; the asteroids and comets; and interplanetary dust and gas.
The dimensions of the solar system are specified in terms of the mean distance from Earth to the Sun, called the astronomical unit (AU).
The solar system was the only planetary system known to exist around a star similar to the Sun until 1995, when astronomers discovered a planet about 0.6 times the mass of Jupiter orbiting the star 51 Pegasi.
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