What Was It Like When The First Habitable Planets Formed?
“The galactic center, however, is a relatively difficult place for a planet to be considered habitable beyond a reasonable doubt. Wherever you have stars continuously forming, you have a spectacular slew of cosmic fireworks. Gamma ray bursts, supernovae, black hole formation, quasars, and collapsing molecular clouds make for an environment that is, at best, precarious for life to arise and sustain in.
To have an environment where we can confidently state that life arises and maintains itself, we need for this process to come to an abrupt end. We need something to put a stop to star formation, which in turn puts the kibosh on the activity that is most threatening to habitability on a world. It’s why the earliest, most sustained habitable planets might not be in a galaxy like ours, but rather in a red-and-dead galaxy that ceased forming stars billions of years ago.”
The cosmic story that created the Universe as we know it had a lot of intricate and fascinating steps along the way. The stars needed to live and die to create heavy elements; enough elements needed to form to make life and rocky planets possible; and the Universe needed to quiet down enough in the richest, locations so that life could sustain and thrive. That last step takes surprisingly long relative to the first few! While rocky planets might come into being less than half-a-billion years after the Big Bang, and life might be able to arise in under a billion years, having the right combination of planets that are habitable and continuously hospitable to life might take up to two billion years, even in the most optimistic of circumstances.
Still, that’s 7 billion years faster than it took for Earth to form! What could life in the Universe that got such a head start on us look like? Consider the possibilities as you learn what it was like when the first habitable planets formed!