The Requirements for Life

There are three essential parts to form human life. The first is that the plant orbits a main sequence star. Secondly the planet must be solid so that there can be a  a liquid solid composition on the surface. The Last is the planet has to be far enough from the star to have liquid water on it. Our solar system stared 4.568 billion years ago with the gravitational collapse of a small molecular cloud. Which formed the sun. The remaining pieces of the cloud flattened into a disk and formed planets. Among all these planets the only one that supports life is Earth. Now scientists can look farther out into the universe, and considering how many star there are they expect to find life out there.