Other celestial bodies of the Solar System

The Sun and the planets are not the only components of the Solar System. It comprises a myriad of other smaller bodies and it extends well beyond the Pluto orbit.
These minor bodies of the Solar System are the comets, the asteroids and the meteorites. They are small rocks, or, in the case of the comets, a mixture of rock and ice. Scientists believe that comets and asteroids formed together with the planets.
Cometa Kohoutek. (NASA)
It is believed that the Solar System formed about 4 and a half billion years ago, out of the collapse of an enormous cloud of gas. This cloud, mostly composed by hydrogen, was initially very expanded and cold. Slowly, it collapsed under the action of its own gravitational force.
The center of the cloud became dense and heated up to 2,000 degrees, later forming a star. You will see further on, that all stars form this way. The rest of the cloud formed out of a big disk rotating about the center. Within the disk, condensations formed, small grains of ice and dust. They very slowly growed up, thanks to the gravitational force attracting the surrounding material.
These tiny particles then collided with each other and attracted, forming pieces of rock, called "planetesimals". The aggregation of the planetesimals eventually produced the asteroids and the planets.
Watch this this video on the birth of the Solar System.
(NASA-JPL), AVI, 3 Mb

In order to see these celestial bodies closer, click below.

[Comets ] [ Asteroids ] [Meteorites ]
[Summary of the Solar System ]