We humans have been consistently wrong about what the universe is like, and where we are in that universe … well, for most of the time we’ve been around.
Our universe is about 13 billion years old, and for roughly 3.5 billion of those years, life has been wriggling all over our planet.
But what was going on in the universe before that time? It’s possible that there was a period shortly after the Big Bang when the entire universe was teeming with life. Harvard astronomer Avi Loeb calls this period the “habitable epoch,” and he believes that its existence changes how humans should understand our place in the cosmos.
In the early universe, Loeb speculates, every place would have been a habitable zone. 10 to 20 million years after the Big Bang, the universe was still bathed in that warm gas we see in the Cosmic Microwave Background [pictured above], but it had cooled down to a temperature that would keep water liquid no matter where it was relative to its star. The ambient temperature of the universe would provide enough heat to turn an ice giant like Neptune into a water giant. That’s why Loeb has dubbed this era the “habitable epoch.”
It would have been a weird time for life to evolve, though. Many of the building blocks of life on Earth, like carbon and metals, exist only because of the massive stellar explosions called supernovas. In the early universe, where so few stars had been born, even fewer would have died. This was a period when solid matter was an anomaly, before most of the elements on the periodic table existed.