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The solar system is our sun and all objects that orbit it. The Oort Cloud is the farthest
part of our solar system, this is where the sun's gravitational affect becomes negligible to
objects. This Oort Cloud is the area that long-period comets originate and is about 100,000 astronomical
units away from the sun. This means that the diameter of the solar system is about 200,000AU.
The solar system is made up of the sun, planets, moons, meteors, asteroids, comets, and all the gas and dust between these objects. Despite all of these things in the solar system, the sun consists of about 99.8% of the mass of the entire solar system. The solar system formed long ago(about 5 billion years) from large amounts of rotating interstellar gas and dust. The nebula that the solar system formed from was probably left from a supernova of a previous star. The formation of the solar system is not understood completely, but the general idea is that the center of the nebula began to fall inward. As more particles fell inward, more were attracted through gravitational forces. The particles in the middle formed a protosun, as the rest of the material in the nebula began to form a large rotating disk. The protosun startes radiating energy once it was large enough. This radiated energy vaporized water and pushed Hydrogen and Helium into the outer parts of the solar system. Larger particles in the disk attracted other particles, chemically at first and then gravitiationally once they were large enough. These would go on to become the planets and the moons of the solar system. As these protoplanets orbited the sun, they would pick up most of the dust and gas throughout the solar system. At some point the protosun reached a mass large enough to start a fusion reaction. This generated large amount of energy which would rid the solar system of large amounts of the gas and dust left. This process is thought to have taken at least a hundred million years. During the early years of its life, the solar system was a very dangerous place to be. For about a billion years after its formation, there were many particles left over that ran into the planets and their moons. There is large amounts of evidence for this on many of the bodies in our solar system, and particularly on our scarred up moon. |
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