The Formation of the Solar System

The Sun and the solar system formed together around 4.6 billion years ago, when the Universe was around 8 billion years old. At the beginning of this process, the starting material was a large interstellar gas cloud, which suddenly collapsed inwards under the pull of its own gravitational self-attraction until it was a fraction of its original size. This decisive event in the planetary system’s earliest history took place so long ago that there are limits in how much can be learned about it by studying the solar system itself, and most of what is known about it has come from studying other nearby star-forming clouds that are still at various stages of ongoing collapse.