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Solar System
Solar System
The Solar System is that part of the Universe that contains the Sun and all the bodies that orbit around it.
Scientists believe the Solar System began when a spinning interstellar cloud (see: Stellar) of gas and dust began to collapse. The more it collapsed, the faster it began to spin (just as ice-skaters spin faster when they draw in their arms), and the more it began to flatten. Eventually, it became a rapidly spinning disk with a central ball of very concentrated gas,
which later formed into the Sun. The Sun now contains 99.9% of the matter in the Solar System.
The Sun was not able to use up all of the material in the cloud, and so it gradually began to form its own clusters of material. Close to the Sun, where it was relatively hot, dust collected to make rocky planets like Earth. Further out
it was cooler, and that allowed
gas as well as dust to accumulate, the gas eventually forming the atmospheres around the gas giants like Jupiter.
As each cluster grew in its own part of the Solar System, its gravity swept most of the surrounding space clear.
It is believed that during the early formation of the Solar System there were over 100 planets. However, some of them collided and were absorbed by the biggest planets, while others were smashed into fragments, some of which now remain as the asteroid belt.
Some moons are believed to have formed as clumps of material
 Solar System—The Solar System as shown in an artist’s impression. Pluto is furthest, then the gas giants, and then the smaller inner rocky planets. At the center lies the Sun.
Sun
Mercury
Mars
Venus
Earth and the Moon
Asteroid belt
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