FACTOID # 10: The total number of state executions in 2005 was 60: 19 in Texas and 41 elsewhere. The racial split was 19 Black and 41 White.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
RELATED ARTICLES
People who viewed "Meteoroid" also viewed:
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Meteoroid
Photo of a part of the sky during a meteor shower over an extended exposure time. The meteors may have actually occurred several seconds to several minutes apart.
Photo of a part of the sky during a meteor shower over an extended exposure time. The meteors may have actually occurred several seconds to several minutes apart.

A meteoroid is a small sand to boulder-sized particle of debris in the Solar system. The visible path of a meteoroid that enters Earth's (or another body's) atmosphere is a meteor, commonly called a "shooting star" or "falling star". Many meteors are part of a meteor shower. The root word meteor comes from the Greek meteōros, meaning high in the air. Wiktionary has related dictionary definitions, such as: meteor Meteor or shooting star may refer to: Meteor, a visible trace of a meteoroid (cf. ... Download high resolution version (1422x1422, 393 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (1422x1422, 393 KB) Wikipedia does not have an article with this exact name. ... A meteor shower, some of which are known as a meteor storm or meteor outburst, is a celestial event where a group of meteors are observed to radiate from one point in the sky. ... The shutter speed dial of a Fujika STX-1. ... For other uses, see Sand (disambiguation). ... This article is about the large rocks. ... This article is about the Solar System. ... This article is about Earth as a planet. ... Air redirects here. ... A meteor shower, some of which are known as a meteor storm or meteor outburst, is a celestial event where a group of meteors are observed to radiate from one point in the sky. ...

Contents

Meteoroid

A meteor (possibly 2) and Milky way
A meteor (possibly 2) and Milky way

A meteoroid is a small sand to boulder-sized particle of debris in the universe. Larger than that, the object is an asteroid; smaller than that, it is interplanetary dust. The current official definition of a meteoroid from the International Astronomical Union is "A solid object moving in interplanetary space, of a size considerably smaller than an asteroid and considerably larger than an atom."[citation needed] The Royal Astronomical Society has proposed a new definition where a meteoroid is between 100 µm and 10 m across.[1] The NEO definition includes larger objects, up to 50 m in diameter, to this category. Image File history File links Metadata Size of this preview: 723 × 600 pixelsFull resolution (2324 × 1928 pixel, file size: 3. ... Image File history File links Metadata Size of this preview: 723 × 600 pixelsFull resolution (2324 × 1928 pixel, file size: 3. ... For other uses, see Milky Way (disambiguation). ... For other uses, see Asteroid (disambiguation). ... It has been suggested that Space dust be merged into this article or section. ... IAU redirects here. ... This article is about the British Society. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... Near-Earth objects (NEO) are asteroids, comets and large meteoroids whose orbit intersects Earths orbit and which may therefore pose a collision danger. ...


Meteor

Comet 17P/Holmes and Geminid

A meteor is the visible event that occurs when a meteoroid or asteroid enters Earth's atmosphere and becomes brightly visible. For bodies with a size scale larger than the atmospheric mean free path (10 cm to several metres) the visibility is due to the heat produced by the ram pressure (not friction, as is commonly assumed) of atmospheric entry. Since the majority of meteors are from small sand-grain size meteoroid bodies, most visible signatures are caused by electron relaxation following the individual collisions between vaporized meteor atoms and atmospheric constituents. The meteor is simply the visible event rather than an object itself.

Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... 17P/Holmes is a periodic comet in our solar system, discovered by the British amateur astronomer Edwin Holmes on November 6, 1892. ... For other uses, see Asteroid (disambiguation). ... In physics, ram pressure is pressure exerted on a body which is moving at supersonic velocity through a fluid medium. ... For other uses, see Friction (disambiguation). ... Atmospheric entry is the transition from the vacuum of space to the atmosphere of any planet or other celestial body. ...


Fireball

A fireball is brighter than a usual meteor. The International Astronomical Union defines a fireball as "a meteor brighter than any of the planets" (magnitude -4 or greater).[2] The International Meteor Organization (an amateur organization that studies meteors) has a more rigid definition. It defines a fireball as a meteor that would have a magnitude of -3 or brighter if seen at zenith. This definition corrects for the greater distance between an observer and a meteor near the horizon. For example, a meteor of magnitude -1 at 5 degrees above the horizon would be classified as a fireball because if the observer had been directly below the meteor it would have appeared as magnitude -6.[3] IAU redirects here. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... The International Meteor Organization (IMO) was founded in 1988 and has several hundred members. ... In broad terms, the zenith is the direction pointing directly above a particular location (perpendicular, orthogonal). ...


Bolide

The word bolide comes from the Greek βολις, (bolis) which can mean a missile or to flash. The IAU has no official definition of bolide and generally considers the term synonymous with fireball. The term is more often used among geologists than astronomers where it means a very large impactor. For example, the USGS uses the term to mean a generic large crater forming projectile "to imply that we do not know the precise nature of the impacting body ... whether it is a rocky or metallic asteroid, or an icy comet, for example".[4] Astronomers tend to use the term to mean an exceptionally bright fireball, particularly one that explodes (sometimes called a detonating fireball). The term bolide (from the Greek βολις, bolis, missile) can refer to either an extraterrestrial body that collides with the Earth, or to an exceptionally bright, fireball-like meteor regardless of whether it ultimately impacts the surface. ... The Geologist by Carl Spitzweg A geologist is a contributor to the science of geology, studying the physical structure and processes of the Earth and planets of the solar system (see planetary geology). ... Galileo is often referred to as the Father of Modern Astronomy. ... InsertSLUTTY WHORES≤ non-formatted text here{| class=toccolours border=1 cellpadding=4 style=float: right; margin: 0 0 1em 1em; width: 20em; border-collapse: collapse; font-size: 95%; clear: right; |+ United States Geological Survey |- |style= align=center colspan=2| [[Image:USGS logo. ...


Meteorite

A meteorite is a portion of a meteoroid or asteroid that survives its passage through the atmosphere and impact with the ground without being destroyed. Meteorites are sometimes, but not always, found in association with hypervelocity impact craters; during energetic collisions, the entire impactor may be vaporized, leaving no meteorites. Willamette Meteorite A meteorite is a natural object originating in outer space that survives an impact with the Earths surface without being destroyed. ... Tycho crater on Earths moon. ...


Tektite

Two tektites
Two tektites

Molten terrestrial material "splashed" from a crater can cool and solidify into an object known as a tektite. These are often mistaken for meteorites. A tektite Tektites (from Greek tektos, molten) are natural glass objects, up to a few centimeters in size, which — according to most scientists — have been formed by the impact of large meteorites on Earths surface, although a few researchers favor an origin from the Moon as volcanic ejecta. ...


Meteoric dust

Most meteoroids are destroyed when they enter the atmosphere. The left-over debris is called meteoric dust or just meteor dust. Meteor dust particles can persist in the atmosphere for up to several months. These particles might affect climate, both by scattering electromagnetic radiation and by catalyzing chemical reactions in the upper atmosphere.


Ionization trails

During the entry of a meteoroid or asteroid into the upper atmosphere, an ionization trail is created, where the molecules in the upper atmosphere are ionized by the passage of the meteor. Such ionization trails can last up to 45 minutes at a time. Small, sand-grain sized meteoroids are entering the atmosphere constantly, essentially every few seconds in a given region, and thus ionization trails can be found in the upper atmosphere more or less continuously. When radio waves are bounced off these trails, it is called meteor burst communications. Earths atmosphere is the layer of gases surrounding the planet Earth and retained by the Earths gravity. ... Ionization is the physical process of converting an atom or molecule into an ion by changing the difference between the number of protons and electrons. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Meteor scatter propogation as used by SNOTEL Meteor burst communications, or MBC for short, is a radio propagation mode that exploits the ionized trails of meteors during atmospheric entry to establish brief communications paths between radio stations up to 2200 kilometers (1400 miles) apart. ...


Meteor radars can measure atmospheric density and winds by measuring the decay rate and Doppler shift of a meteor trail. Radioactive decay is the set of various processes by which unstable atomic nuclei emit subatomic particles (radiation). ... The Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ...


Sound

Numerous people have over the years reported sounds being heard while bright meteors flared overhead. This would seem impossible, given the relatively slow speed of sound. Any sound generated by a meteor in the upper atmosphere, such as a sonic boom, should not be heard until many seconds after the meteor disappeared. However, in certain instances, for example during the Leonid meteor shower of 2001, several people reported sounds described as "crackling", "swishing", or "hissing"[5] occurring at the same instant as a meteor flare. Similar sounds have also been reported during intense displays of Earth's auroras. 1966 Leonid Meteor Shower The Leonids are a prolific meteor shower associated with the comet Tempel-Tuttle. ... 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. ...


Many investigators believe the sounds to be imaginary... essentially sound effects added by the mind to go along with a light show. However, the persistence and consistency of the reports have caused others to wonder. And sound recordings made under controlled conditions in Mongolia in 1998 by a team lead by Slaven Garaj, a physicist at the Swiss Federal Institute of Technology at Lausanne, support the contention that the sounds are real. Location: Polytechnic of Lausanne, in western Switzerland The École Polytechnique Fédérale de Lausanne (EPFL) is the Swiss Federal Institute of Technology in Lausanne, Switzerland. ... Lausanne (pronounced ) is a city in the French-speaking part of Switzerland, situated on the shores of Lake Geneva (French: Lac Léman), and facing Évian-les-Bains (France) and with the Jura mountains to its north. ...


How these sounds could be generated, assuming they are in fact real, remains something of a mystery. It has been hypothesized that the turbulent ionized wake of a meteor interacts with the magnetic field of the Earth, generating pulses of radio waves. As the trail dissipates, megawatts of electromagnetic energy could be released, with a peak in the power spectrum at audio frequencies. Physical vibrations induced by the electromagnetic impulses would then be heard if they are powerful enough to make grasses, plants, eyeglass frames, and other conductive materials vibrate.[6][7][8][9] This proposed mechanism, although proven to be plausible by laboratory work, remains unsupported by corresponding measurements in the field. The megawatt (symbol: MW) is a unit for measuring power corresponding to one million (106) watts. ... The power spectrum is a plot of the portion of a signals power (energy per unit time) falling within given frequency bins. ... An audio frequency (abbreviation: AF) is any frequency from about 20 hertz to about 20 kilohertz, which is the approximate range of sound frequencies that is audible to humans. ...


Formation

Many meteoroids are formed by impacts between asteroids though many are also left in trails behind comets that form meteor showers and many members of those trails are eventually scattered into other orbits forming random meteors too. Other sources of meteors are known to have come from impacts on the Moon, or Mars as some meteorites from them have been identified. See Lunar meteorites and Mars meteorites. Comet Hale-Bopp, showing a white dust tail and blue gas tail (February 1997) A comet is a small astronomical object similar to an asteroid but composed largely of ice. ... Categories: Planetology | Astronomy stubs ... This article is about Earths moon. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Lunar Meteorite Allan Hills 81005 A Lunar meteorite is a meteorite that is known to have originated on the Moon. ... A Martian meteorite is a meteorite, that has landed on Earth but is believed to have originated from Mars. ...


Orbit

Meteoroids and asteroids orbit around the Sun, in greatly differing orbits. Some of these objects orbit together in streams; these are probably comet remnants that would form a meteor shower. Other meteoroids are not associated with any stream clustering (although there must also be meteoroids clustered in orbits which do not intercept Earth's or any other planet). The fastest objects travel at roughly 42 kilometers per second (26 miles per second) through space in the vicinity of Earth's orbit. Together with the Earth's orbital motion of 29 km/s (18 miles per second), collision speeds can reach 71 km/s (44 miles per second) during head-on collisions. This would only occur if the meteor were in a retrograde orbit. Meteors have roughly a fifty percent chance of a daylight (or near daylight) collision with the Earth as the Earth orbits in the direction of roughly west at noon. Most meteors are however, observed at night as low light conditions allow fainter meteors to be observed. Meteors are usually seen when they are 60 to 120 km (40 to 75 miles) above the ground.[10] A meteor shower, some of which are known as a meteor storm or meteor outburst, is a celestial event where a group of meteors are observed to radiate from one point in the sky. ... This article is about retrograde motion. ...


A number of specific meteors have been observed, largely by members of the public and largely by accident, but with enough detail that orbits of the incoming meteors or meteorites have been calculated. All of them came from orbits from the vicinity of the Asteroid Belt.[11] For other uses, see Asteroid (disambiguation). ...


Perhaps the best-known meteor/meteorite fall is the Peekskill Meteorite which was filmed on October 9, 1992 by at least 16 independent videographers.[12] The Peekskill Meteorite over Pittsburgh, Pennsylvania. ... is the 282nd day of the year (283rd in leap years) in the Gregorian calendar. ... Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ...


Eyewitness accounts indicate that the fireball entry of the Peekskill meteorite started over West Virginia at 23:48 UT (±1 min). The fireball, which traveled in a northeasterly direction had a pronounced greenish colour, and attained an estimated peak visual magnitude of -13. During a luminous flight time that exceeded 40 seconds the fireball covered a ground path of some 700 to 800 km.


One meteorite recovered at Peekskill, N.Y., for which the event and object gained its name, (at 41.28 deg. N, 81.92 deg. W) had a mass of 12.4 kg (27 lb) and was subsequently identified as an H6 monomict breccia meteorite.[13] The video record suggests that the Peekskill meteorite probably had several companions over a wide area especially in the harsh terrain in the vicinity of Peekskill.


Spacecraft damage

Even very small meteoroids can damage spacecraft. The Hubble Space Telescope for example, has about 572 tiny craters and chipped areas.[14] The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ...


Gallery

See also

Wikimedia Commons has media related to:
Look up meteor in
Wiktionary, the free dictionary.
Look up meteoroid in
Wiktionary, the free dictionary.

Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... The International Meteor Organization (IMO) was founded in 1988 and has several hundred members. ... The American Meteor Society, Ltd. ... Baetylus or Bethel is a semitic word denoting a sacred stone, which was supposed to be endowed with life. ... Tycho crater on Earths moon. ... A meteor shower, some of which are known as a meteor storm or meteor outburst, is a celestial event where a group of meteors are observed to radiate from one point in the sky. ... Willamette Meteorite A meteorite is a natural object originating in outer space that survives an impact with the Earths surface without being destroyed. ... A tektite Tektites (from Greek tektos, molten) are natural glass objects, up to a few centimeters in size, which — according to most scientists — have been formed by the impact of large meteorites on Earths surface, although a few researchers favor an origin from the Moon as volcanic ejecta. ... Alexander Tollmanns bolide, proposed by Kristen-Tollmann and Tollmann (1994), is a hypothesis presented by Austrian professor of geology Dr. Alexander Tollmann, suggesting that one or several bolides (asteroids or comets) struck the Earth at 7640 BCE (±200), with a much smaller one at 3150 BCE (±200). ... A number of so-called Green Fireballs were reported in the skies of the southwestern United States, particularly New Mexico, beginning in late 1948. ... Artists impression of a major impact event. ...

References

  1. ^ Beech, M.; Steel, D. I. (September 1995). "On the Definition of the Term Meteoroid". Quarterly Journal of the Royal Astronomical Society 36 (3): 281–284. Retrieved on 2006-08-31. )
  2. ^ MeteorObs Explanations and Definitions (states IAU definition of a fireball)
  3. ^ International Meteor Organization - Fireball Observations
  4. ^ usgs.gov - What is a Bolide?
  5. ^ Psst! Sounds like a meteor: in the debate about whether or not meteors make noise, skeptics have had the upper hand until now - Now Hear This | Natural History | Find Articles at BNET.com
  6. ^ Listening to Leonids
  7. ^ Hearing Sensations in Electric Fields
  8. ^ Human auditory system response to Modulated electromagnetic energy.
  9. ^ Human Perception of Illumination with Pulsed Ultrahigh-Frequency Electromagnetic Energy
  10. ^ NASA Home > World Book @ NASA, Meteors
  11. ^ Diagram 2: the orbit of the Peekskill meteorite along with the orbits derived for several other meteorite falls
  12. ^ The Peekskill Meteorite October 9, 1992 Videos
  13. ^ "Meteoritical Bull", by Wlotzka, F. published in "Meteoritics", # 75, 28, (5), 692, 1994.
  14. ^ SPACE.com - How Hubble Has Survived a Decade of Impacts

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. ... is the 282nd day of the year (283rd in leap years) in the Gregorian calendar. ... Year 1992 (MCMXCII) was a leap year starting on Wednesday (link will display full 1992 Gregorian calendar). ...

External links

CBC redirects here, as this is the most common use of the abbreviation. ... This article is about the Solar System. ... Sol redirects here. ... 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. ... Spectral type: G[8] Absolute magnitude: 3. ... For other uses, see Jupiter (disambiguation). ... This article is about the planet. ... For other uses, see Uranus (disambiguation). ... For other uses, see Neptune (disambiguation). ... For other uses, see Pluto (disambiguation). ... Absolute magnitude: −1. ... This article is about the astronomical term. ... Artists impression of Pluto (background) and Charon (foreground). ... 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. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale : Phobos (top) and Deimos (bottom). ... Jupiters 4 Galilean moons, in a composite image comparing their sizes and the size of Jupiter (Great Red Spot visible). ... The Saturnian system (photographic montage) Moons of Saturn (photographic montage) Saturn has 60 confirmed natural satellites, plus three hypothetical moons. ... Uranus has twenty-seven known moons. ... Neptune (top) and Triton (bottom), 3 days after the Voyager 2 flyby. ... Hubble image of the Plutonian system Pluto has three known moons. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... 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). ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... For other uses, see Asteroid (disambiguation). ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... 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. ... Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... Artists rendering of the Oort cloud and the Kuiper Belt. ... 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. ...

  Results from FactBites:
 
Meteoroids and Meteorites (1526 words)
A meteoroid is matter revolving around the sun or any object in interplanetary space that is too small to be called an asteroid or a comet.
A meteorite is a meteoroid that reaches the surface of the Earth without being completely vaporized.
One of the primary goals of studying meteorites is to determine the history and origin of their parent bodies.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m