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Encyclopedia > Meteor shower

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. These meteors are small fragments of cosmic debris entering Earth's atmosphere at extremely high speed. They vaporize due to friction with the air, leaving a streak of light that very quickly disappears. For bodies with a size scale larger than the atmospheric mean free path (10 cm to several metres) this visible light is due to the heat produced by the ram pressure (not friction, as is commonly assumed) of atmospheric entry [1]. Most of the small fragments of cosmic debris are smaller than a grain of sand, so almost all fragments disintegrate and never hit the earth's surface. Fragments which do contact Earth's surface are called meteorites. Worlds second largest Meteorite in Culiacan, Mexico A meteorite is a relatively small extra-terrestrial body that reaches the Earths surface. ... This article is about Earth as a planet. ... View of Jupiters active atmosphere, including the Great Red Spot. ... Worlds second largest Meteorite in Culiacan, Mexico A meteorite is a relatively small extra-terrestrial body that reaches the Earths surface. ...

Contents

The causes of meteor showers

Comet Encke's meteoroid trail is the diagonal red glow
Comet Encke's meteoroid trail is the diagonal red glow
Meteoroid trail between fragments of Comet 73P
Meteoroid trail between fragments of Comet 73P

A meteor shower is the result of an interaction between a planet (Earth in our case) and a comet. Comets are like "dirty snowballs" made up of ice and rock, orbiting the Sun. Each time a comet swings by the Sun in its orbit, some of its ice melts and it sheds a large amount of debris. As the debris streams from the comet, it forms the comet's visible tail. The solid pieces of debris are a form of meteoroid. The meteoroids spread out along the entire orbit of the comet to form a meteoroid "stream". As the Earth orbits the Sun, its orbit sometimes takes us through a meteoroid stream and a meteor shower ensues. The meteoroids encounter Earth's atmosphere at high speed. As the meteoroids streak through the atmosphere, friction causes the particles to burn and incandesce, forming meteors. When the meteoroid stream is particularly dense, we occasionally see a spectacular "meteor storm." The comets that spawn most known meteor showers have been identified. Image File history File links Download high-resolution version (720x900, 90 KB) from medium resolution option at http://www. ... Image File history File links Download high-resolution version (720x900, 90 KB) from medium resolution option at http://www. ... Comet Encke (officially designated 2P/Encke) is a periodic comet, named after Johann Franz Encke, who through laborious study of its orbit and many calculations was able to link multiple observations in 1786 (2P/1786 B1), 1795 (2P/1795 V1), 1805 (2P/1805 U1) and 1818 (2P/1818 W1) to... Image File history File links Download high-resolution version (900x621, 151 KB) from medium resolution option at http://sscws1. ... Image File history File links Download high-resolution version (900x621, 151 KB) from medium resolution option at http://sscws1. ... 73P/Schwassmann-Wachmann, also known as Schwassmann-Wachmann 3, is a periodic comet in our solar system which is in the process of disintegrating. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... Sol redirects here. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... “Meteor” redirects here. ...


Irish astronomer George Johnstone Stoney (1826-1911), collaborating with British astronomer Arthur Matthew Weld Downing (1850-1917), and independently Adolf Berberich of the Königlichen Astronomischen Rechen Instituts in Berlin, Germany, have offered apparently the first idea of a meteoroid stream or trail in the 1890s, when they calculated how meteroids, once freed from the comet and traveling at low speeds relative to the comet, would drift mostly in front of or behind the comet after completing one orbit. The effect is simple orbital mechanics - the material drifts only a little laterally away from the comet while drifting ahead or behind the comet because some particles make a wider orbit than others. [1] These dust trails are sometimes observed in comet images taken at mid infrared wavelengths (heat radiation), where dust particles from the previous return to the Sun are spread along the orbit of the comet (see figures). George Johnstone Stoney (February 15, 1826 РJuly 5, 1911) was an Irish physicist. ... Arthur Matthew Weld Downing (April 13, 1850 РDecember 8, 1917) was a British astronomer. ... This article or section should be merged with Celestial Mechanics Astrodynamics is the study and creation of orbits, especially those of artificial satellites. ...


The gravitational pull of the planets determines where the dust trail would pass by Earth orbit, much like a gardener directing a hose to water a distant plant. Most years, those trails would miss the Earth altogether, but in some years the Earth is showered by meteoroids.


In 1985, E. D. Kondrat'eva and E. A. Reznikov of Kazan State University first correctly identified the years when dust was released responsible for several past Leonid meteor storms. In anticipation of the 1999 Leonid storm, Robert McNaught[2] and David Asher[3], and Esko Lyytinen of Finland, were first to apply this method in the West. [4][5] Peter Jenniskens has published predictions for future dust trail encounters, resulting in a "meteor storm" or "meteor outburst", for the next 50 years. [6] Robert H. McNaught is an Australian astronomer at the Research School of Astronomy and Astrophysics of the Australian National University. ... This article or section does not cite any references or sources. ... Meteor astronomer Dr. Peter Jenniskens (b. ...


Over longer periods of time, the dust trails can evolve into complicated ways. One effect is that the orbits of some repeating comets, and meteoroids leaving them, are in resonant orbits with Jupiter or one of the other large planets - so many revolutions of one will equal another number of revolutions of the other. So over time since Jupiter will have the same relative position intermittently and it will tend to pull meteoroids into keeping that relative position. This creates a shower component called a "filament". In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other, usually due to their orbital periods being related by a ratio of two small integers. ... For other uses, see Jupiter (disambiguation). ...


A second effect is a close encounter with a planet. When the meteoroids pass by Earth, some are accelerated (making wider orbits), others are decelerated (making shorter orbits), resulting in gaps in the dust trail in the next return (like opening a curtain, with grains piling up at the beginning and end of the gap). Also, Jupiter's perturbation can change sections of the dust trail dramatically, especially for short period comets, when the grains approach the big planet at their furthest point along the orbit around the Sun, moving most slowly. As a result, the trail has a clumping, a braiding or a tangling of crescents, of each individual release of material.


The third effect is that of radiation pressure which will push less massive particles into orbits further from the sun - while more massive objects (responsible for bolides or fireballs) will tend to be affected less by radiation pressure. This makes some dust trail encounters rich in bright meteors, others rich in faint meteors. Over time, these effects disperse the meteoroids and create a broader stream. The meteors we see from these streams are part of annual showers, because Earth encounters those streams every year at much the same rate. Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. ... 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. ... Look up fireball in Wiktionary, the free dictionary. ...


When the meteoroids collide with other meteoroids in the zodiacal cloud, they lose their stream association and become part of the "sporadic meteors" background. Long since dispersed from any stream or trail, they form isolated meteors, not a part of any shower. These random meteors will not appear to come from the radiant of the main shower. Zodiacal dust forms a pancake shaped cloud in the Solar System collectively known as the zodiacal cloud. ...


Meteor showers originate from fixed points in the sky

Because meteor shower particles are all traveling in parallel paths, and at the same velocity, they will all appear to an observer below to radiate away from a single point among the constellations. This radiant point is caused by the effect of perspective, similar to railroad tracks converging at a single vanishing point on the horizon when viewed from the middle of the tracks. Meteor showers are almost always named after the constellation from which the meteors appear to originate. This "fixed point" slowly moves across the sky during the night due to the Earth turning on its axis, the same reason the stars appear to slowly march across the sky. The radiant also moves slightly from night to night against the background stars (radiant drift) due to the Earth moving in its orbit around the sun. See "IMO" Meteor Shower Calendar 2007(International Meteor Organization) for maps of drifting "fixed points". The radiant or apparent radiant of a meteor shower is the point in the sky that (to a planetary observer) meteors appear to originate from. ... A cube in two-point perspective. ... The International Meteor Organization (IMO) was founded in 1988 and has several hundred members. ...


Most famous meteor showers

The most visible meteor shower in most years are the Perseids, which peak on August 12th of each year at over 1 meteor a minute. The tone or style of this article or section may not be appropriate for Wikipedia. ...


The most spectacular meteor shower is probably the Leonids, the King of Meteor Showers.[7] Approximately every 33 years the Leonid shower produces a "meteor storm" with hundreds of thousands of meteors per hour. These Leonid storms gave birth to the term "meteor shower" since most meteor showers produce only a few meteors per hour, rarely producing as many as one meteor every 30 seconds. The last two massive Leonid storms were in 1933 and 1966. The anticipated storm of 1999 was much less spectacular. When the Leonid shower is not storming it is less active than the Perseids. The most famous depiction of the 1833 meteor storm actually produced in 1889 for the Adventist book Bible Readings for the Home Circle based on a first-person account of the 1833 storm by a minister, Joseph Harvey Waggoner on his way from Florida to New Orleans. ...


Other important meteor showers

Shower time parent object
Quadrantids Early January Minor planet 2003 EH1, suffered a catastrophic breakup in 1490.[8]
Lyrids late April Comet Thatcher
Pi Puppids late April Comet 26P/Grigg-Skjellerup
Eta Aquarids early May Comet 1P/Halley
Arietids mid June Marsden Sungrazer Group
June Bootids late June Comet 7P/Pons-Winnecke
Southern Delta Aquarids late July Kracht or Machholz Sungrazer Groups
Perseids mid-August Comet 109P/Swift-Tuttle
Draconids early October Comet 21P/Giacobini-Zinner
Orionids late October Comet 1P/Halley
Southern Taurids early November Comet 2P/Encke and others
Northern Taurids mid-November Minor planet 2004 TG10 and others
Leonids mid-November Comet 55P/Tempel-Tuttle
Geminids mid-December Minor planet 3200 Phaethon
Ursids late December Comet 8P/Tuttle

The Quadrantids are a meteor shower. ... The Lyrids are a strong meteor shower lasting from April 15 to April 28 each year. ... Non-periodic comets are seen on only one occasion. ... The Pi Puppids are a meteor shower associated with the comet Comet Grigg-Skjellerup 26P. The meteor stream was viewable around April 23 but only in years around the parent comets perihelion date, the last being in 2003. ... Comet Grigg-Skjellerup (formally designated 26P/Grigg-Skjellerup) is a periodic comet. ... The Eta Aquarids are a meteor shower associated with Comet Halley. ... (Redirected from 1P/Halley) Comet Halley as taken with the Halley Multicolor Camera on the ESA Giotto mission. ... The Arietids are a strong meteor shower that lasts from May 22 to July 2 each year, and peaks on June 7. ... The June Bootids are a meteor shower occurring roughly between 26 June and 2 July each year. ... 7P/Pons-Winnecke is a periodic comet in our solar system. ... The Southern Delta Aquarids are a meteor shower visible from mid July to mid August each year with peak activity on July 28th or 29th. ... The tone or style of this article or section may not be appropriate for Wikipedia. ... Comet Swift-Tuttle (formally designated as 109P/Swift-Tuttle) was independently discovered by Lewis Swift on July 15, 1868 and by Horace Parnell Tuttle on July 5, 1868. ... The Giacobinids (also known as the Draconids) are a meteor shower whose parent body is the periodic comet 21P/Giacobini-Zinner. ... Comet Giacobini-Zinner was discovered by Michel Giacobini (Nice, France) in Aquarius on December 20, 1900. ... The Orionids are a meteor shower that occurs throughout October into early November. ... (Redirected from 1P/Halley) Comet Halley as taken with the Halley Multicolor Camera on the ESA Giotto mission. ... The Taurids are an annual meteor shower associated with the comet Encke. ... Comet Encke (officially designated 2P/Encke) is a periodic comet, named after Johann Franz Encke, who through laborious study of its orbit and many calculations was able to link multiple observations in the years 1786, 1795, 1805 and 1818 to the same object. ... The Taurids are an annual meteor shower associated with the comet Encke. ... The most famous depiction of the 1833 meteor storm actually produced in 1889 for the Adventist book Bible Readings for the Home Circle based on a first-person account of the 1833 storm by a minister, Joseph Harvey Waggoner on his way from Florida to New Orleans. ... Comet Tempel-Tuttle (formally designated as 55P/Tempel-Tuttle) was independently discovered by Ernst Tempel on December 19, 1865 and by Horace Parnell Tuttle on January 6, 1866. ... The Geminids are a meteor shower caused by an object named 3200 Phaethon, which is thought to be an extinct comet. ... 3200 Phaethon (sometimes incorrectly spelled Phaeton) is an Apollo and Mercury-, Venus- and Mars_crosser asteroid with unusual properties, and may be an extinct comet. ... The Ursids meteor activity begins annually around December 17th and runs for a week plus, until the 24th or 25th. ... 8P/Tuttle is a periodic comet in our solar system. ...

Extraterrestrial meteor showers

Any other solar system body with a reasonably transparent atmosphere can also have meteor showers. For instance, Mars is known to have meteor showers, although these are different from the ones seen on Earth because the different orbits of Mars and Earth intersect orbits of comets in different ways. Because of the similar air pressure at altitudes for meteors only the relatively slower motion because of increased distance from the sun should marginally decrease meteor brightness.[9] On March 7, 2004, the panoramic camera on Mars Exploration Rover Spirit recorded a streak which is now believed to have been caused by a meteor from a Martian meteor shower associated with comet 114P/Wiseman-Skiff. A strong display from this shower is expected on December 20, 2007. Other showers speculated about are a "Lambda Geminid" shower associated with the Eta Aquarids of Earth (ie both associated with Comet 1P/Halley), a "Beta Canis Major" shower associated with Comet 13P/Olbers, and "Draconids" from 5335 Damocles.[10] is the 66th day of the year (67th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Artists Concept of Rover on Mars (credit: Maas Digital LLC) NASAs Mars Exploration Rover (MER) Mission is an ongoing robotic mission of exploring Mars, that began in 2003 with the sending of two rovers — Spirit and Opportunity — to explore the Martian surface and geology. ... Spirit (official designation: MER-A) is the first of the two Mars Exploration Rover Missions. ... 114P/Wiseman-Skiff is a periodic comet in our solar system. ... is the 354th day of the year (355th 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. ... The Eta Aquarids are a meteor shower associated with Comet Halley. ... This article is about the comet. ... 13P/Olbers is a periodic comet in our solar system. ... 5335 Damocles is the archetype of the Damocloids, astroids that are inactive nuclei of Halley Family and long period comets. ...


See also

Photo of a burst of meteors with extended exposure time A meteor is the visible path of a meteoroid that enters the Earths (or another bodys) atmosphere, commonly called a shooting star or falling star. ... 253 Mathilde, a C-type asteroid. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... Zenith Hourly Rate is a concept used by meteor shower observers. ... Meteor showers ALPO meteor showers list SPA meteor showers list International Meteor Organization 2006 meteor shower calendar (Pdf) Categories: | ...

References

  1. ^ Jenniskens P., Meteor Showers and their Parent Comets. Cambridge University Press, Cambridge, U.K., 790 pp.
  2. ^ Re: (meteorobs) Leonid Storm? By Rob McNaught
  3. ^ Blast from the Past Armagh Observatory press release 1999 April 21st.
  4. ^ Royal Astronomical Society Press Notice Ref. PN 99/27, Issued by: Dr Jacqueline Mitton RAS Press Officer]
  5. ^ Voyage through a comet's trail, The 1998 Leonids sparkled over Canada By BBC Science's Dr Chris Riley on board NASA's Leonid mission
  6. ^ Jenniskens P., Meteor Showers and their Parent Comets. Cambridge University Press, Cambridge, U.K., 790 pp.
  7. ^ Meteor Storms (Leonids)
  8. ^ Peter Jenniskens. 2003 EH1 is the Quadrantid shower parent comet. Submitted 08-12-2003. San Jose Astronomical Association Ephemeris
  9. ^ Can Meteors Exist at Mars?
  10. ^ Meteor Showers and their Parent Bodies

External links


  Results from FactBites:
 
AMS Meteor Shower FAQ (3261 words)
Meteor showers are usually named for the constellation in which their radiant lies at the time of shower maximum.
Meteor storms are generally caused by young meteor streams, in which the majority of the streams' mass is still concentrated along that portion of the orbit occupied by the parent comet.
Meteor storms occur when the Earth crosses the orbit of the meteor stream, at the same time that the main mass of the young meteor stream is crossing the orbit of the Earth.
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