The largest asteroids and their movement
Any cosmic body with a diameter of more than 3 kilometers threatens the Earth when confronted with the disappearance of civilization. Therefore, it is important to know about the largest asteroids and their movement on the orbits, because among 670 thousand objects in the Solar system, there are very unusual instances. The bulk of large celestial bodies is located in the so-called asteroid belt, far from Earth, so no direct threat. As the discovery they were called by female names from Roman and Greek mythology, and then, with the increase in the number of discoveries, it has ceased to be respected.
It is a small celestial body (diameter 975*909 km) who just was not since: and a full-fledged planet of the Solar system, and asteroid, and since 2006 has acquired a new status of dwarf planet. The latter name is most correct, since Ceres is not a major in its orbit, and only the biggest in the asteroid belt. Discovered it quite by accident, the Italian astronomer Piazzi in 1801.
Ceres has a spherical shape (which is unusual for asteroids) with a stone core and crust of water ice and minerals. The distance between the nearest point of the orbit of this satellite of the Sun and Earth 263 million kilometers. Its path lies between Mars and Jupiter, but there is some tendency to chaotic motion (which increases the chances of a collision with other asteroids change orbits). To the naked eye from the surface of our planet it is not visible is a star only 7 values.
Size 582*556 kilometers, and it is also part of the asteroid belt. The angle of the axis of rotation of Pallas is very high — 34 degrees (the other celestial bodies do not exceed 10). Pallas orbits with a high degree of deviation, why it is the distance to the Sun changes all the time. It is a carbon asteroid, rich in silicon and is of interest in the future from the point of view of mining.
This is the most difficult asteroid to date, though inferior in size to the previous one. Because of the breed composition of Vesta reflects 4 times more light than the same Ceres, although its diameter in half. It turns out that it is the only asteroid whose motion can be observed with the naked eye from the Earth’s surface, as it comes once in 3-4 years on the minimum distance of 177 million kilometers. Her motion carried by the inner part of the asteroid belt and never crosses our orbit.
Interestingly, with a length of 576 kilometers on the surface is a crater 460 kilometers. Actually, the entire asteroid belt around Jupiter is a giant quarry where the heavenly bodies are colliding, ripping apart and changing their orbits – but how Vesta survived a collision with such a large object and has retained its integrity, remains a mystery. Its core consists of a heavy metal, and crust of light rock.
This asteroid does not intersect with our orbit and revolves around the Sun. Very dim celestial body, though has a diameter of 407 kilometers, was opened later than the other. This is the most common type of asteroids of carbon content. Usually watching Gigia required a telescope, but in the moment of greatest proximity to the Earth it can be seen through binoculars.
Today an asteroid falling to Earth, will bring casualties, destruction and disasters. But in spite of what astronomers call this moon «space debris», it is to them we owe the appearance of life on our planet. In 2010, independently from each other, two groups of researchers found on the asteroid Themis (part of the 20 largest) water ice, hydrocarbons and complex molecules whose isotopic composition coincides with the earth.