Currently, the earliest sign of life on Earth is from 3.83 billion years ago. During this period, a series of formidable meteor showers occurred. This heavy barrage of comets colliding into Earth suggests that any life that was forming at that time would have certainly faced extinction.
Remember the dinosaurs? Meteors are no joke. That was just one meteor the size of Mount Everest, but it made the Earth’s surface hotter than the Sun after crashing “20 times faster than a bullet.” While it seems apparent that these fireballs of fury snuffed out any life on Earth, they may have also been vessels for the life to come.
Evolution is agonizingly slow. It took several billion years for single-cell life to become multicellular, for example. So, how is it that directly after the most epic meteor shower our planet has ever seen, Earth was ripe and ready to spontaneously spawn DNA-based life? The planet hardly had time to cool down enough to support life, let alone create it.
The period of meteor showers ended sometime earlier than approximately 3.8 billion years ago. Evidence of life shows up in the fossil records from 3.83 billion years ago. If Earth was cooling down then, life evolved in the blink of an eye from an evolutionary standpoint. Unless, of course, life had already arrived. Many scientists hold these ancient fossil records as evidence of panspermia.