What Was It Like When Life In The Universe First Became Possible?
“We still don’t know how life in the Universe got its start, or whether life as we know it is common, rare, or a once-in-a-Universe proposition. But we can be certain that life came about in our cosmos at least once, and that it was built out of the heavy elements made from previous generations of stars. If we look at how stars theoretically form in young star clusters and early galaxies, we could reach that abundance threshold after several hundred million years; all that remains is putting those atoms together in a favorable-to-life arrangement. If we form the molecules necessary for life and put them in an environment conducive to life arising from non-life, suddenly the emergence of biology could have come when the Universe was just a few percent of its current age. The earliest life in the Universe, we must conclude, could have been possible before it was even a billion years old.”
When the Universe was first born, life was absolutely impossible. There were no planets for life to reside on; there were no organic molecules to self-replicate; there were no energy gradients or sources of heat and light; there weren’t even heavy elements or neutral atoms. In order for life to exist, the Universe had quite a bit of work to do.
Our Earth formed after more than 9 billion years of cosmic evolution, and life began on our planet shortly after that. But there’s no reason to believe that Earth is the only world with life on it; in fact, if we put everything we know about the Universe together, many other locations should have gotten there billions of years earlier.