Meteoroids [ meteoroi dən ː ] ( ancient Greek μετέωρα, celestial phenomena ', the suffix- identical from Ancient Greek ιδεῖν be similar ') are small objects in the solar system in orbit around the sun, some of which cross the Earth's orbit. They range in size from fractions of a millimeter ( micrometeoroids ) up to several meters, equivalent to a mass from milligrams to tons.
Meteoroid are greater than and less than the interplanetary asteroids. Between meteoroids and asteroids there is a definite limit as regards either size nor the composition.
Together with the asteroids and comets are meteoroids to the small bodies of the solar system.
If meteoroids in the Earth's atmosphere, they ( by friction ) generated by the ionization of air particles recombination following a luminous phenomenon, called Meteor. Through the air compression before the meteoroid produces a likewise ionized and bright glowing ball of gas from the air heated and vaporized, initially solid matter. Small meteors are also known as shooting stars, big as fireballs or bolides.
One may not fully verglühter meteoroid that reaches the earth's surface is called a meteorite.
Meteoroids are of different origin. They may have been removed, these lose their path and thus fall into a meteor stream by the gravitation of the planet from the asteroid belt, but also by the solar wind from cometary nuclei. The term Meteoroidenstrom would indeed be correct, but is not common. Furthermore, they may be made by impact or collision also feature material from asteroids, dwarf planets or planets. So meteorites found on Earth, probably from Mars and the Moon come (see: Mars meteorite, lunar meteorite ). However, the vast number of meteorites found on Earth came from asteroids.
Risk for space
Even ask for space micrometeoroids a risk, since their impact energy is so high that even lead parts with the size of fractions of a millimeter to considerable destruction.
Until the mid-20th century meteoroids were referred to as " meteorites " and meteorites rather than " meteorites ". Thereafter, in addition to the term " meteorite ", the term " meteorite " was introduced as a synonym. A meteorite is therefore in the broader sense, both are still in interplanetary space driving as well (in the narrow sense) have been designated which came to the surface objects. Since the early 1990s, was also the former until then mainly common in Anglo-Saxon term " meteoroid " usual.
For the term " meteoroid " also spelled " meteoroid " is often used, which is probably due to the word " meteorite " or a mix with " meteoroid ". The notation " meteoroid " is indeed in common parlance more often, but rarely used in the literature, since the former distinguish the terms ( the only site-specific names) is usually not as accurate or possibly use adjectives for a more accurate distinction.