Requirements for Life Molecules capable of combining in complex forms. Proteins A fairly stable environment with a flow of Energy through it. Earth s climate fairly stable. Sun is main energy source. Earth s climate has changed but never too catastrophically.
Temperature is right for liquid water.
Allows organic molecules mainly made of Carbon, Hydrogen, Nitrogen, Oxygen, and sometimes Phosphorous and Sulfur. Perturbations from the other planets seem to have remained too small to seriously disturb Earth's motion. Now, surface is cold and gets lots of UV from Sun, thin atmosphere, no liquid water. Mostly water ice. Interior liquid due to heat from tidal distortion.