Meteor shower
Encyclopedia
A meteor shower is a celestial event
in which a number of meteor
s are observed to radiate from one point in the night sky
. These meteors are caused by streams of cosmic debris called meteoroid
s entering Earth's atmosphere
at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. Intense or unusual meteor showers are known as meteor outbursts and meteor storms, which may produce greater than 1,000 meteors an hour.
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."
Meteor showers are named after the nearest bright star with a Greek or Roman letter assigned that is close to the radiant position at the peak of the shower, whereby the declension of the Latin possessive form is replaced by "id" or "ids". Hence, meteors radiating from near the star delta Aquarii (declension "-i") are called delta Aquariids. The International Astronomical Union's Task Group on Meteor Shower Nomenclature and the IAU's Meteor Data Center keep track of meteor shower nomenclature and which showers are established.
A meteor shower is the result of an interaction between a planet, such as Earth, and streams of debris from a comet
.
Comets can produce debris by water vapor drag, as demonstrated by Fred Whipple in 1951, and by breakup. Whipple envisioned comets as "dirty snowballs," made up of rock embedded in ice, orbiting the Sun
. The "ice" may be water
, methane
, ammonia
, or other volatiles
, alone or in combination. The "rock" may vary in size from that of a dust mote to that of a small boulder. Dust mote sized solids are orders of magnitude more common than those the size of sand grains, which, in turn, are similarly more common than those the size of pebbles, and so on. When the ice warms and sublimates, the vapor can drag along dust, sand, and pebbles. Each time a comet swings by the Sun in its orbit
, some of its ice vaporizes and a certain amount of meteoroids will be shed. The meteoroids spread out along the entire orbit of the comet to form a meteoroid stream, also known as a "dust trail" (as opposed to a comet's "dust tail" caused by the very small particles that are quickly blown away by solar radiation pressure).
Recently, Peter Jenniskens
has argued that most of our short-period meteor showers are not from the normal water vapor drag of active comets, but the product of infrequent disintegrations, when large chunks break off a mostly dormant comet. Examples are the Quadrantids
and Geminids
, which originated from a breakup of asteroid-looking objects 2003 EH1
and 3200 Phaethon
, respectively, about 500 and 1000 years ago. The fragments tend to fall apart quickly into dust, sand, and pebbles, and spread out along the orbit of the comet to form a dense meteoroid stream, which subsequently evolves into Earth's path.
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 meteors. This effect was first demonstrated from observations of the 1995 alpha Monocerotids
, and from earlier not widely known identifications of past earth storms.
In the 1890s, Irish astronomer George Johnstone Stoney
(1826–1911) and British astronomer Arthur Matthew Weld Downing
(1850–1917), were the first to attempt to calculate the position of the dust at Earth's orbit. They studied the dust ejected in 1866 by comet 55P/Tempel-Tuttle in advance of the anticipated Leonid shower return of 1898 and 1899. Meteor storms were anticipated, but the final calculations showed that most of the dust would be far inside of Earth's orbit. The same results were independently arrived at by Adolf Berberich of the Königliches Astronomisches Rechen Institut (Royal Astronomical Computation Institute) in Berlin, Germany. Although the absence of meteor storms that season confirmed the calculations, the advance of much better computing tools was needed to arrive at reliable predictions.
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 H. McNaught
David Asher, and Finland's Esko Lyytinen were the first to apply this method in the West. Peter Jenniskens
has published predictions for future dust trail encounters, resulting in "meteor storms" or "meteor outbursts" for the next 50 years.
Over longer periods of time, the dust trails can evolve in 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."
A second effect is a close encounter with a planet. When the meteoroids pass by Earth, some are accelerated (making wider orbits around the Sun), 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 fireball
s) 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.
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.
, which peak on August 12 of each year at over 1 meteor a minute. A useful tool to calculate how many meteors per hour are visible from your observing location is found here: http://leonid.arc.nasa.gov/estimator.html.
The most spectacular meteor shower is probably the Leonids
, the King of Meteor Showers which peaks on a day near 17 November. Approximately every 33 years the Leonid shower produces a "meteor storm", peaking at rates of thousands of meteors per hour. These Leonid storms gave birth to the term "meteor shower", when it was first realised during the November 1833 storm that the meteors radiated from near the star Gamma Leonis. The last Leonid storms were in 1999, 2001 (two), and 2002 (two). Before that, there were storms in 1767, 1799, 1833, 1866, 1867, and 1966. When the Leonid shower is not storming it is less active than the Perseids.
Although the Martian atmosphere has less than one percent of the density of Earth's at ground level, at their upper edges, where meteoroids strike, the two are more similar. Because of the similar air pressure at altitudes for meteors, the effects are much the same. Only the relatively slower motion of the meteoroids due to increased distance from the sun should marginally decrease meteor brightness. This is somewhat balanced in that the slower descent means that Martian meteors have more time in which to ablate.
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 was expected on December 20, 2007. Other showers speculated about are a "Lambda Geminid" shower associated with the Eta Aquariids of Earth (i.e., both associated with Comet 1P/Halley), a "Beta Canis Major" shower associated with Comet 13P/Olbers, and "Draconids" from 5335 Damocles
.
Celestial event
A celestial event is an astronomical phenomenon of interest that involves one or more celestial bodies. Examples of celestial events include the various phases of the Moon, meteor showers, comets, solar and lunar eclipses, planetary oppositions, conjunctions, and occultations....
in which a number of meteor
METEOR
METEOR is a metric for the evaluation of machine translation output. The metric is based on the harmonic mean of unigram precision and recall, with recall weighted higher than precision...
s are observed to radiate from one point in the night sky
Night sky
The term night sky refers to the sky as seen at night. The term is usually associated with astronomy, with reference to views of celestial bodies such as stars, the Moon, and planets that become visible on a clear night after the Sun has set. Natural light sources in a night sky include moonlight,...
. These meteors are caused by streams of cosmic debris called meteoroid
Meteoroid
A meteoroid is a sand- to boulder-sized particle of debris in the Solar System. The visible path of a meteoroid that enters Earth's atmosphere is called a meteor, or colloquially a shooting star or falling star. If a meteoroid reaches the ground and survives impact, then it is called a meteorite...
s entering Earth's atmosphere
Earth's atmosphere
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
at extremely high speeds on parallel trajectories. Most meteors are smaller than a grain of sand, so almost all of them disintegrate and never hit the Earth's surface. Intense or unusual meteor showers are known as meteor outbursts and meteor storms, which may produce greater than 1,000 meteors an hour.
The radiant point
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 in the sky. This radiantRadiant (meteor shower)
The radiant or apparent radiant of a meteor shower is the point in the sky, from which meteors appear to originate. The Perseids, for example, are meteors which appear to come from a point within the constellation of Perseus....
point is caused by the effect of perspective
Perspective (graphical)
Perspective in the graphic arts, such as drawing, is an approximate representation, on a flat surface , of an image as it is seen by the eye...
, 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
International Meteor Organization
The International Meteor Organization was founded in 1988 and has several hundred members. IMO was created in response to an ever-growing need for international cooperation on amateur meteor work...
) for maps of drifting "fixed points."
Meteor showers are named after the nearest bright star with a Greek or Roman letter assigned that is close to the radiant position at the peak of the shower, whereby the declension of the Latin possessive form is replaced by "id" or "ids". Hence, meteors radiating from near the star delta Aquarii (declension "-i") are called delta Aquariids. The International Astronomical Union's Task Group on Meteor Shower Nomenclature and the IAU's Meteor Data Center keep track of meteor shower nomenclature and which showers are established.
The origin of meteoroid streams
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
.
Comets can produce debris by water vapor drag, as demonstrated by Fred Whipple in 1951, and by breakup. Whipple envisioned comets as "dirty snowballs," made up of rock embedded in ice, orbiting the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
. The "ice" may be water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...
, ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, or other volatiles
Volatiles
In planetary science, volatiles are that group of chemical elements and chemical compounds with low boiling points that are associated with a planet's or moon's crust and/or atmosphere. Examples include nitrogen, water, carbon dioxide, ammonia, hydrogen, and methane, all compounds of C, H, O...
, alone or in combination. The "rock" may vary in size from that of a dust mote to that of a small boulder. Dust mote sized solids are orders of magnitude more common than those the size of sand grains, which, in turn, are similarly more common than those the size of pebbles, and so on. When the ice warms and sublimates, the vapor can drag along dust, sand, and pebbles. Each time a comet swings by the Sun in its orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
, some of its ice vaporizes and a certain amount of meteoroids will be shed. The meteoroids spread out along the entire orbit of the comet to form a meteoroid stream, also known as a "dust trail" (as opposed to a comet's "dust tail" caused by the very small particles that are quickly blown away by solar radiation pressure).
Recently, Peter Jenniskens
Peter Jenniskens
Petrus Matheus Marie Jenniskens is a Dutch astronomer and a senior research scientist at the Carl Sagan Center of the SETI Institute and at NASA Ames Research Center. He is an expert on meteor showers. Jenniskens is the author of the 790 page book "Meteor Showers and their Parent Comets"...
has argued that most of our short-period meteor showers are not from the normal water vapor drag of active comets, but the product of infrequent disintegrations, when large chunks break off a mostly dormant comet. Examples are the Quadrantids
Quadrantids
The Quadrantids are an easily visible January meteor shower.The radiant of this shower is an area inside the constellation Boötes. The name comes from Quadrans Muralis, an obsolete constellation that is now part of Boötes...
and Geminids
Geminids
The Geminids are a meteor shower caused by the object 3200 Phaethon, which is thought to be a Palladian asteroid. This would make the Geminids, together with the Quadrantids, the only major meteor showers not originating from a comet...
, which originated from a breakup of asteroid-looking objects 2003 EH1
2003 EH1
2003 EH1 is a celestial body.This astronomical body was discovered during March of 2003. P.Jenniskens proposed the asteroid as the parent of the Quadrantid meteor shower. - Sources : retrieved 15:18 13 October 2011...
and 3200 Phaethon
3200 Phaethon
3200 Phaethon is an asteroid with an unusual orbit that brings it closer to the Sun than any other named asteroid . For this reason, it was named after the Greek myth of Phaëton, son of the sun god Helios...
, respectively, about 500 and 1000 years ago. The fragments tend to fall apart quickly into dust, sand, and pebbles, and spread out along the orbit of the comet to form a dense meteoroid stream, which subsequently evolves into Earth's path.
The dynamical evolution of meteoroid streams
Shortly after Whipple predicted that dust particles travelled at low speeds relative to the comet, Milos Plavec was the first to offer the idea of a dust trail, when he calculated how meteroids, once freed from 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. 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).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 meteors. This effect was first demonstrated from observations of the 1995 alpha Monocerotids
Alpha Monocerotids
The Alpha Monocerotids or Monocerotids of November is it a meteor swarm with the international acronym AMO, not to be confused with the Monocerotids of December, international acronym MON. The swarm is visible from 15 to 25 November of every year; its peak occurs on 21 or 22 November. The speed of...
, and from earlier not widely known identifications of past earth storms.
In the 1890s, Irish astronomer George Johnstone Stoney
George Johnstone Stoney
George Johnstone Stoney was an Irish physicist most famous for introducing the term electron as the "fundamental unit quantity of electricity"....
(1826–1911) and British astronomer Arthur Matthew Weld Downing
Arthur Matthew Weld Downing
Arthur Matthew Weld Downing was a British astronomer.He was born in Carlow, Ireland.He became an assistant at the Royal Greenwich Observatory in 1873. He became superintendent of HM Nautical Almanac Office from 1891 to 1910. He was elected a Fellow of the Royal Society in June 1896 He...
(1850–1917), were the first to attempt to calculate the position of the dust at Earth's orbit. They studied the dust ejected in 1866 by comet 55P/Tempel-Tuttle in advance of the anticipated Leonid shower return of 1898 and 1899. Meteor storms were anticipated, but the final calculations showed that most of the dust would be far inside of Earth's orbit. The same results were independently arrived at by Adolf Berberich of the Königliches Astronomisches Rechen Institut (Royal Astronomical Computation Institute) in Berlin, Germany. Although the absence of meteor storms that season confirmed the calculations, the advance of much better computing tools was needed to arrive at reliable predictions.
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 H. McNaught
Robert H. McNaught
Robert H. McNaught is a Scottish-Australian astronomer at the Research School of Astronomy and Astrophysics of the Australian National University. He has collaborated with David J. Asher of the Armagh Observatory....
David Asher, and Finland's Esko Lyytinen were the first to apply this method in the West. Peter Jenniskens
Peter Jenniskens
Petrus Matheus Marie Jenniskens is a Dutch astronomer and a senior research scientist at the Carl Sagan Center of the SETI Institute and at NASA Ames Research Center. He is an expert on meteor showers. Jenniskens is the author of the 790 page book "Meteor Showers and their Parent Comets"...
has published predictions for future dust trail encounters, resulting in "meteor storms" or "meteor outbursts" for the next 50 years.
Over longer periods of time, the dust trails can evolve in complicated ways. One effect is that the orbits of some repeating comets, and meteoroids leaving them, are in resonant orbits with Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
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."
A second effect is a close encounter with a planet. When the meteoroids pass by Earth, some are accelerated (making wider orbits around the Sun), 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
Radiation pressure
Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. If absorbed, the pressure is the power flux density divided by the speed of light...
which will push less massive particles into orbits further from the sun - while more massive objects (responsible for bolides or fireball
Glowworm (astronomy)
A glowworm is a luminous trail of a tiny meteor, occasionally visible in the night sky during a meteor shower.The centimeter-sized comet pieces can produce hundreds of fireballs or more each hour...
s) 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.
When the meteoroids collide with other meteoroids in the zodiacal cloud
Zodiacal dust
The Zodiacal dust cloud is visible as a diffuse glow, known as the zodiacal light, that stretches along the zodiac, and is best seen just after sunset and before sunrise in spring and autumn when the zodiac is at a steep angle to the horizon....
, 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.
Perseid and Leonid meteor showers
The most visible meteor shower in most years are the PerseidsPerseids
The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle. The Perseids are so-called because the point from which they appear to come, called the radiant, lies in the constellation Perseus. The name derives in part from the word Perseides , a term found in Greek mythology...
, which peak on August 12 of each year at over 1 meteor a minute. A useful tool to calculate how many meteors per hour are visible from your observing location is found here: http://leonid.arc.nasa.gov/estimator.html.
The most spectacular meteor shower is probably the Leonids
Leonids
The Leonids is a prolific meteor shower associated with the comet Tempel-Tuttle. The Leonids get their name from the location of their radiant in the constellation Leo: the meteors appear to radiate from that point in the sky. They tend to peak in November.Earth moves through the meteoroid...
, the King of Meteor Showers which peaks on a day near 17 November. Approximately every 33 years the Leonid shower produces a "meteor storm", peaking at rates of thousands of meteors per hour. These Leonid storms gave birth to the term "meteor shower", when it was first realised during the November 1833 storm that the meteors radiated from near the star Gamma Leonis. The last Leonid storms were in 1999, 2001 (two), and 2002 (two). Before that, there were storms in 1767, 1799, 1833, 1866, 1867, and 1966. When the Leonid shower is not storming it is less active than the Perseids.
Other notable meteor showers
Official names are given in the International Astronomical Union meteor shower list.| Shower | Time | Parent object |
|---|---|---|
| Quadrantids Quadrantids The Quadrantids are an easily visible January meteor shower.The radiant of this shower is an area inside the constellation Boötes. The name comes from Quadrans Muralis, an obsolete constellation that is now part of Boötes... |
Early January | The same as the parent object of minor planet , and perhaps comets C/1490 Y1 and C/1385 U1 |
| Lyrids Lyrids The Lyrids are a strong meteor shower lasting from April 16 to April 26 each year. The radiant of the meteor shower is located in the constellation Lyra, peaking at April 22—hence they are also called the Alpha Lyrids or April Lyrids. The source of the meteor shower is the periodic Comet... |
late April | Comet Thatcher |
| Pi Puppids Pi Puppids The Pi Puppids are a meteor shower associated with the comet 26P/Grigg-Skjellerup.The meteor stream was viewable around April 23 but only in years around the parent comet's perihelion date, the last being in 2003... (periodic) |
late April | Comet 26P/Grigg-Skjellerup 26P/Grigg-Skjellerup Comet Grigg–Skjellerup is a periodic comet.Discovered in 1902 by John Grigg of New Zealand, and rediscovered in its next appearance in 1922 by John Francis Skjellerup, an Australian then living and working for about two decades in South Africa where he was a founder member of the Astronomical... |
| Eta Aquariids | early May | Comet 1P/Halley |
| Arietids Arietids The Arietids are a strong meteor shower that lasts from May 22 to July 2 each year, and peaks on June 7. The Arietids, along with the Zeta Perseids, are the most intense daylight meteor showers of the year... |
mid June | Comet 96P/Machholz 96P/Machholz Comet 96P/Machholz or 96P/Machholz 1 is a short-period comet discovered on May 12, 1986 by amateur astronomer Donald Machholz in Loma Prieta, California. Comet 96P/Machholz will next come to perihelion on July 14, 2012.... , Marsden and Kracht comet groups complex |
| June Bootids June Bootids The June Bootids are a meteor shower occurring roughly between 26 June and 2 July each year. In most years their activity is weak, with a zenith hourly rate of only 1 or 2. However, occasional outbursts have been seen, with the outburst of 1916 drawing attention to the previously unknown meteor... (periodic) |
late June | Comet 7P/Pons-Winnecke 7P/Pons-Winnecke 7P/Pons–Winnecke is a periodic comet in our solar system.Jean Louis Pons originally discovered the comet on June 12, 1819, it was later rediscovered by Friedrich August Theodor Winnecke on March 9, 1858. It is believed to be the parent body of the June Bootids of late June.7P has an orbital... |
| Southern Delta Aquariids | late July | Comet 96P/Machholz 96P/Machholz Comet 96P/Machholz or 96P/Machholz 1 is a short-period comet discovered on May 12, 1986 by amateur astronomer Donald Machholz in Loma Prieta, California. Comet 96P/Machholz will next come to perihelion on July 14, 2012.... , Marsden and Kracht comet groups complex |
| Alpha Capricornids Alpha Capricornids Alpha Capricornids is a meteor shower that takes place as early as 15 July and continues until around 10 August. The meteor shower was discovered by Hungarian astronomer Miklos von Konkoly-Thege in 1871.This shower has infrequent but relatively bright meteors, with some fireballs... |
late July | Comet 169P/NEAT 169P/NEAT 169/NEAT is a periodic comet in our solar system. It is the parent body of the alpha Capricornids meteor shower.- External links :*... |
| Perseids Perseids The Perseids are a prolific meteor shower associated with the comet Swift-Tuttle. The Perseids are so-called because the point from which they appear to come, called the radiant, lies in the constellation Perseus. The name derives in part from the word Perseides , a term found in Greek mythology... |
mid-August | Comet 109P/Swift-Tuttle |
| Kappa Cygnids Kappa Cygnids Kappa Cygnids, abbreviated KCG, is a minor meteor shower that takes place in August along with the larger Perseids meteor shower. Kappa Cygnids are named for the radiant where the meteor shower will appear to line up in sky by the constellation Cygnus and the star Kappa Cygni.... |
mid-August | Minor planet 2008 ED69 |
| Aurigids Aurigids Aurigids is the name of a meteor shower occurring primarily within September.The comet Kiess is the source of the material that causes the meteors. The comets orbital period is stated as approximately 1800 to 2000 years, with showers observed in the years 1935, '86, '94 and '07 .-α & δ:The... (periodic) |
early September | Comet C/1911 N1 (Kiess) |
| Draconids Draconids The October Draconids, in the past also unofficially known as the Giacobinids, are a meteor shower whose parent body is the periodic comet 21P/Giacobini-Zinner. A Draconid meteor shower is expected to happen in early October of 2011, and the best nights for viewing are expected to be October... (periodic) |
early October | Comet 21P/Giacobini-Zinner 21P/Giacobini-Zinner Comet Giacobini–Zinner is a periodic comet in our solar system.It was discovered by Michel Giacobini from , who observed the comet in the constellation of Aquarius on December 20, 1900... |
| Orionids Orionids The Orionid meteor shower, usually shortened to the Orionids, is the most prolific meteor shower associated with Halley's Comet. The Orionids are so-called because the point they appear to come from, called the radiant, lies in the constellation Orion. Orionids are an annual meteor shower which... |
late October | Comet 1P/Halley |
| Southern Taurids | early November | Comet 2P/Encke |
| Northern Taurids | mid-November | Minor planet and others |
| Andromedids Andromedids The Andromedids meteor shower is associated with the comet 3D/Biela, the showers occurring as the earth's orbit passes through the tail of the comet... (periodic) |
mid-November | Comet 3D/Biela 3D/Biela Biela's Comet or Comet Biela was a periodic comet first recorded in 1772 by Montaigne and Messier and finally identified as periodic in 1826 by Wilhelm von Biela. It was subsequently observed to split in two and has not been seen since 1852... |
| Alpha Monocerotids Alpha Monocerotids The Alpha Monocerotids or Monocerotids of November is it a meteor swarm with the international acronym AMO, not to be confused with the Monocerotids of December, international acronym MON. The swarm is visible from 15 to 25 November of every year; its peak occurs on 21 or 22 November. The speed of... (periodic) |
mid-November | unknown |
| Leonids Leonids The Leonids is a prolific meteor shower associated with the comet Tempel-Tuttle. The Leonids get their name from the location of their radiant in the constellation Leo: the meteors appear to radiate from that point in the sky. They tend to peak in November.Earth moves through the meteoroid... |
mid-November | Comet 55P/Tempel-Tuttle 55P/Tempel-Tuttle 55P/Tempel–Tuttle is a comet that was independently discovered by Ernst Tempel on December 19, 1865 and by Horace Parnell Tuttle on January 6, 1866.It is the parent body of the Leonid meteor shower... |
| Phoenicids Phoenicids The Phoenicids are a minor meteor shower, first noticed by observers in New Zealand, Australia, the Indian Ocean, and South Africa during an outburst of approximately 100 meteors an hour that occurred during December 1956. Like other meteor showers, the Phoenicids get their name from the location... (periodic) |
early-December | Comet D/1819 W1 (Blanpain) D/1819 W1 (Blanpain) D/1819 W1 is a short-period comet that was discovered by Jean-Jacques Blanpain on November 28, 1819. Blanplain described the comet as having a "very small and confused nucleus". Another independent discovery was made on December 5 of that year by J. L. Pons. Following this the comet was lost, and... |
| Geminids Geminids The Geminids are a meteor shower caused by the object 3200 Phaethon, which is thought to be a Palladian asteroid. This would make the Geminids, together with the Quadrantids, the only major meteor showers not originating from a comet... |
mid-December | Minor planet 3200 Phaethon 3200 Phaethon 3200 Phaethon is an asteroid with an unusual orbit that brings it closer to the Sun than any other named asteroid . For this reason, it was named after the Greek myth of Phaëton, son of the sun god Helios... |
| Ursids Ursids The Ursids meteor activity begins annually around December 17th and runs for a week plus, until the 25th or 26th. This meteor shower is named for its radiant point which is located near the star Beta Ursae Minoris in the constellation Ursa Minor.... |
late December | Comet 8P/Tuttle 8P/Tuttle 8P/Tuttle is a periodic comet in our solar system. Perihelion was late January 2008, and as of February was visible telescopically to Southern Hemisphere observers in the constellation Eridanus. On December 30, 2007 it was in close conjunction with spiral galaxy M33... |
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.Although the Martian atmosphere has less than one percent of the density of Earth's at ground level, at their upper edges, where meteoroids strike, the two are more similar. Because of the similar air pressure at altitudes for meteors, the effects are much the same. Only the relatively slower motion of the meteoroids due to increased distance from the sun should marginally decrease meteor brightness. This is somewhat balanced in that the slower descent means that Martian meteors have more time in which to ablate.
On March 7, 2004, the panoramic camera on Mars Exploration Rover
Mars Exploration Rover
NASA's Mars Exploration Rover Mission is an ongoing robotic space mission involving two rovers, Spirit and Opportunity, exploring the planet Mars...
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
114P/Wiseman-Skiff
114P/Wiseman-Skiff is a periodic comet in our solar system.It was discovered by Jennifer Wiseman in January of 1987 on two photographic plates that had been taken on December 28, 1986, by Brian A. Skiff of Lowell Observatory...
. A strong display from this shower was expected on December 20, 2007. Other showers speculated about are a "Lambda Geminid" shower associated with the Eta Aquariids of Earth (i.e., both associated with Comet 1P/Halley), a "Beta Canis Major" shower associated with Comet 13P/Olbers, and "Draconids" from 5335 Damocles
5335 Damocles
5335 Damocles is the archetype of the Damocloids, asteroids that are inactive nuclei of the Halley Family and long-period comets. It was discovered in 1991 and named after Damocles, a figure of Greek mythology....
.
See also
- International Meteor OrganizationInternational Meteor OrganizationThe International Meteor Organization was founded in 1988 and has several hundred members. IMO was created in response to an ever-growing need for international cooperation on amateur meteor work...
(IMO) - American Meteor SocietyAmerican Meteor SocietyThe American Meteor Society, Ltd. is a non-profit scientific organization established to encourage and support the research activities of both amateur and professional astronomers who are interested in the field of Meteor Astronomy...
(AMS) - North American Meteor NetworkNorth American Meteor NetworkThe North American Meteor Network was established in June 1995 as an electronic network of people using the Internet to share an interest in meteors...
- List of meteor showers
- Meteor processionMeteor processionA meteor procession is the term used to describe when an Earth-grazing meteor breaks apart, and the fragments travel across the sky in the same path...
- Earth-grazing fireballEarth-grazing fireballAn Earth-grazing fireball is a small solar system body that enters the Earth's atmosphere and leaves again. If it starts to break up in the atmosphere it can become an Earth-grazing meteor procession, and some fragments may impact the Earth...
- RadiantRadiant (meteor shower)The radiant or apparent radiant of a meteor shower is the point in the sky, from which meteors appear to originate. The Perseids, for example, are meteors which appear to come from a point within the constellation of Perseus....
, a point in the sky, from which (to a planetary observer) meteors appear to originate. - Zenith Hourly Rate
External links
- Basics of Meteor Observing, by Sky and Telescope
- Worldwide viewing times for 2011 meteor showers
- Infography about Meteor Showers
- North American Meteor Network
- Live Meteor Screen
- Meteor Shower Photos and Info (AOL Research & Learn)
- Meteor Showers, by Sky and Telescope
- Meteor showers Astronomy CastAstronomy CastAstronomy Cast is an educational nonprofit podcast discussing various topics in the field of astronomy. The specific subject matter of each episode shifts from week to week, ranging from planets and stars to cosmology and mythbusting...
episode #8, includes full transcript in PDF-format. - Meteor Showers Online , by Gary W. Kronk
- Meteor Streams
- National Geographic News - Sky-Watcher Alert: Meteor Show Peaks This Week
- Six Not-So-Famous Summer Meteor Showers Joe Rao (SPACE.com)
- The American Meteor Society
- The International Meteor Organisation
- The Space Book by Eonitus