A planet that is a candidate for being inhabited will no doubt experience catastrophes, collisions, and extinction-level events on it. If life is to survive and thrive on a world, it must possess the right intrinsic and environmental conditions to allow it to persist. Here, an illustration of early Earth’s environment may look fearsome, but life somehow still found a way. (NASA GODDARD SPACE FLIGHT CENTER)

What Was It Like When Life Began On Earth?

The planet has had life on it, in some form or another, for nearly as long as Earth has existed.

If you came to our Solar System right after it formed, you would have seen a completely foreign-looking sight. Our Sun would have been about the same mass it is today, but only about 80% as luminous, as stars heat up as they age…