How are asteroids different from comets?

Gouse Basha By Gouse Basha , 10th Dec 2012 | Follow this author | RSS Feed | Short URL http://nut.bz/2gdc5dyp/
Posted in Wikinut>News>Science

Asteroids are small bodies that are made up chiefly of rocks and metals.Most asteroids orbit the Sun in the wide asteroids belt, which lies between the orbits of Mars and Jupiter ,on the other hand ,are made up of a loose mixture of rocks and ice, and for this reason they are often called 'dirty snowballs'.

Asteroids-Comets

Asteroids are small bodies that are made up chiefly of rocks and metals.Most asteroids orbit the Sun in the wide asteroids belt, which lies between the orbits of Mars and Jupiter ,on the other hand ,are made up of a loose mixture of rocks and ice, and for this reason they are often called 'dirty snowballs'.However ,recent research has shown that rocks are the main constituent of most comets.

Astronomers think that far beyond Neptune's orbit our solar system is surrounded by a shell made up of several billion comets, known as the Oort Cloud. Although the largest asteroids can be several hundred kilometers in diameter, most comets are only a few kilometers across. Comets only attract the attention of the general public when gravitational forces at work in the Oort Cloud send them on a path that takes them into the inner solar system. As they approach the Sun, volatile constituents vaporise and from a gas and dust tail which can be more than 100 million km long and clearly visible from Earth.
Are asteroids the remains of a planet that exploded in the past?
At one time, some astronomers believed that the asteroids between Mars and Jupiter were the remains of a planet that had been destroyed by a catastrophe.Today,however,it is generally thought that the strong gravitational pull exerted by Jupiter in the region of the asteroid belt made it impossible for another planet to from there.Hence,asteroids are more likely to be the remains of small bodies-known as planetesimals from which the earth-like planets were formed about 4.5 billion years ago.

Nonetheless, most of the asteroids seen today are thought to be fragments of what were once much larger bodies that have been smashed into pieces by collisions between the original planetesimals over millennia. This probably explains the fact that there are several different kinds of asteroids,with 'rocky' asteroids having been formed from the crust of ancient planetisimals and 'metallic' asteroids from deeper internal material.

What is a dead comet?

Every time a comet approach the Sun it loses of its mass as frozen gases and ice evaporate and are blown into space. A comet orbiting closer to the Sun than Jupiter has an active life of only about 10 000 years. After that it is 'dead' it no longer has a tail and is easily mistaken for an asteroid. Thanks to recent research, we also know that the dividing line between asteroids and comets is blurred. There are bodies within the asteroid belt that constantly emit dust, triggered by the evaporation of ice, just as it the case with comets.

Tags

Asteroids, Dirty Snowballs, Metal, Orbits, Rocks

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author avatar Gouse Basha
Hi i am gouse .

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author avatar Stella Mitchell
17th Dec 2012 (#)

Very interesting Gouse.. bless you

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author avatar Terry Trainor
18th Dec 2012 (#)

Great stuff I am very interested by space and what goes on. The unanswerable question, is the universe is expanding is something I am always puzzling about. I know that it is not part of your post but it brought it to minds

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