page_title: Meteoroid
section_title: Meteor shower
hierarchical_section_title: Meteoroid / Meteors / Meteor shower
caption_attribution_description: English: This picture is of the Alpha-Monocerotid meteor outburst in 1995. The Perseid meteor shower, usually the richest meteor shower of the year, peaks in August. Over the course of an hour, a person watching a clear sky from a dark location might see as many as 50-100 meteors. Meteors are actually pieces of rock that have broken off a comet and continue to orbit the Sun. The Earth travels through the comet debris in its orbit. As the small pieces enter the Earth's atmosphere, friction causes them to burn up. Français&#160;: Image de l'explosion de météore Alpha-Monocerotid en 1995. La douche de météore Perseid, d'habitude la douche de météore la plus riche de l'année, atteint un niveau maximal en août. Pour la durée d'une heure, une personne observant un ciel clair d'un emplacement sombre pourrait voir bien 50-100 météores. Les météores sont en réalité les pièces de roche (rock) d'une comète et continuent à l'orbite autour du Soleil. La Terre voyage par les débris de comète dans son orbite. Comme les petites pièces entrent dans l'Atmosphère de la terre, la friction cause qu'ils brûlent en haut.
context_page_description: A meteoroid is a small rocky or metallic body in outer space.
  Meteoroids are significantly smaller than asteroids, and range in size from small grains to one-meter-wide objects. Objects smaller than this are classified as micrometeoroids or space dust. Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars.
  When a meteoroid, comet, or asteroid enters Earth's atmosphere at a speed typically in excess of 20 km/s, aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor or "shooting star". A series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a meteor shower. If that object withstands ablation from its passage through the atmosphere as a meteor and impacts with the ground, it is then called a meteorite.
context_section_description: A meteor shower is the result of an interaction between a planet, such as Earth, and streams of debris from a comet or other source. The passage of Earth through cosmic debris from comets and other sources is a recurring event in many cases. Comets can produce debris by water vapor drag, as demonstrated by Fred Whipple in 1951, and by breakup. 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).
  The frequency of fireball sightings increases by about 10–30% during the weeks of vernal equinox. Even meteorite falls are more common during the northern hemisphere's spring season. Although this phenomenon has been known for quite some time, the reason behind the anomaly is not fully understood by scientists. Some researchers attribute this to an intrinsic variation in the meteoroid population along Earth's orbit, with a peak in big fireball-producing debris around spring and early summer. Others have pointed out that during this period the ecliptic is (in the northern hemisphere) high in the sky in the late afternoon and early evening. This means that fireball radiants with an asteroidal source are high in the sky (facilitating relatively high rates) at the moment the meteoroids "catch up" with Earth, coming from behind going in the same direction as Earth. This causes relatively low relative speeds and from this low entry speeds, which facilitates survival of meteorites. It also generates high fireball rates in the early evening, increasing chances of eyewitness reports. This explains a part, but perhaps not all of the seasonal variation. Research is in progress for mapping the orbits of the meteors to gain a better understanding of the phenomenon.
caption: Multiple meteors photographed over an extended exposure time during a meteor shower
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