The Study of Comets and Asteroids

Astronomers divide the comets into two groups. Because it takes time to run around the sun, short and long comets. Short-term comets are within 200 years, but long-term comets take over 200 years. Astronomers suspect that short-period comets come from the Kuiper belt, which is basically a band of objects close to the orbit of Pluto. They believe that the pulling by the gravity of the planet will move the celestial body to the solar system and become a comet.

So far, the spacecraft has detected 11 comets and asteroids as shown below. ICE will fly above comet Giacobini-Zinner. Many of the missions to the Halley comet are in flight. Giotto (changed position) Comet Grigg - Skellerup. Galileo 's asteroid Gaspra and Ida (and Ida satellite Daktil). Nearby shoe makers jumped over the asteroid Matilde to the Eros track and land. DS-1 flight of asteroid braille and comet Borelli. Asteroid fly of asteroid Annefrank and sample collection of recent comet Wild 2. Hayabusa (MUSES-C) to the asteroid Itokawa, Rosetta to the comet Churyumov-Gerasmenko, deep shock of the comet Tempel 1, the dawn to the orbiting asteroid Vesta and Ceres

Asteroids are different from comets and meteors. In the case of a comet the difference lies in the composition: the asteroid mainly consists of minerals and rocks, and the comet consists of dust and ice. In addition, asteroids are formed near the sun and prevent the formation of the above comet ice. The difference between asteroids and meteors is mainly size: meteor diameters are less than 1 meter and asteroid diameters are over 1 meter. Finally, the meteoroid body can consist of comet and asteroid materials.

As the sun goes past 500 degrees, most of the comet's ice and gas will be lost and objects like rocks like asteroids will remain. A comet close to the sun can hit either the planet or the sun, or it can be driven out of the solar system by the solar system. Intimate contact (especially with Jupiter). When the earth passes through the orbit of the comet, meteor shower sometimes occurs. Sometimes it happens on a regular basis. Perseid meteor shower occurs when Earth passes the orbit of Swift-Tower comet from 9th to 13th August every year. Halley's comet is the source of the shower of Orion in October.

Some of the thousands of known comets are very unusual. Enke Comet runs from the main asteroid belt to the orbit of Mercury, but 29P / Schwassmann-Wachmann comet runs almost orbetween Jupiter and Saturn. In 2060, the unstable orbits of Chiron were located between Saturn and Uranus and were originally classified as asteroids until weak coma was found. Similarly, the shoe maker - Levy 2 comet was originally called asteroid 1990 UL 3. Some asteroids close to the Earth are considered to be the core of comet extinction, they no longer experience degassing