bulk of the asteroids discovered by scientists (about 98%) is located between the planetary orbits of Jupiter and Mars.Their removal from the sun varies within the limits of 2,06-4,30 well.e., for the periods of the oscillations have the following scope - 2,9-8,92 year.In the group of small planets, there are those who have a unique orbit.These asteroids are obtained, as a rule, men's names.The most popular are the names of the heroes of Greek mythology - Eros, Icarus, Adonis, Hermes.These small planets move beyond the asteroid belt.Removing them from the Earth varies, asteroids can approach it for 6 - 23 million. Km.A unique approach to Earth was in 1937, Small Planet Hermes approached her 580 thousand. Km.This distance is 1.5 times the distance of the moon from Earth.

most striking of known asteroids Vesta is considered (about 6m).The large mass of small planets have intense shine, during the confrontation (7m - 16m).

calculation widths asteroids carried out by brilliance, ability to reflection of vi
sible and infrared light.
From 3.5 thousand. Only 14 of the list of asteroids have a transverse dimension greater than 250 km.The rest is much more modest, there is even asteroids with a diameter of 0.7 km. largest known asteroids - Ceres, Pallas, Vesta and Gigiya (from 1,000 to 450 km).Small asteroids do not have a spheroid shape, they are more similar to the shapeless lumps.

Asteroid - Pallas

Asteroid Vesta asteroid Vesta

also fluctuate and the masses of asteroids.The biggest weight is defined for Ceres, it is 4,000 times smaller than the Earth.The mass of all asteroids are also smaller than the mass of our planet and is a thousandth of it.

All minor planets have an atmosphere.Some of them have axial rotation that is set regularly detectable change in the light.Thus, the palladium has a rotation period of 7.9 hours, and Icarus refers only 2 hours and 16 minutes.

By reflectance of asteroids, they were combined into 3 groups - metal, light and dark.The latter group includes asteroids, the surface of which can reflect no more than 5% of the incident solar light.Their surface is formed similar to carbonaceous rocks and black basalt.For this reason, dark carbonaceous asteroids were named.

most highly reflective bright asteroids (10-25%).These celestial bodies are similar to the surface of the silicon compounds.They are called asteroids of stone.Less commonly found metallic asteroids.They are similar to light, the surface of these bodies is more reminiscent of alloys of iron and nickel.

correctness of such a classification is confirmed by the chemical composition of the incident on the surface of the Earth meteorites.Provided small group of asteroids, is not to be classified according to this principle.Percentages shown 3 groups of asteroids following: dark (type C) - 75% lighter (Type S) - 15% and 10% of metal (Type M).

minimum performance reflectance of asteroids are 3-4%, and the maximum amount to 40% of incident light.The fastest rotating asteroids is small in size, they are very diverse in form.Presumably they are composed of matter formed the solar system.Confirmation of this hypothesis is the change in the dominant type asteroids belonging to the asteroid belt away from the sun.
In its motion of the asteroid will inevitably collide with each other, while flying away into small pieces.

pressure inside the asteroid is not large, so they are not observed warming.Their surface may be slightly heated by solar radiation, but heat is not delayed, and goes into the space.Estimated figures asteroids surface temperature range from -120 ° C to -100 ° C.A significant increase in temperature, for example, to +730 ° C (Icarus) can be registered only in the moments of the approximation to the sun.After removal of the asteroid from him a sharp cooling.
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