Earthlings may be extreme latecomers to a universe full of life, with alien microbes possibly teeming on exoplanets beginning just 15 million years after the Big Bang, new research suggests.
Traditionally, astrobiologists keen on solving the mystery of the origin of life in the universe look for planets in habitable zones around stars. Also known as Goldilocks zones, these regions are considered to be just the right distance away from stars for liquid water, a pre-requisite for life as we know it, to exist.
But even exoplanets that orbit far beyond the habitable zone may have been able to support life in the distant past, warmed by the relic radiation left over from the Big Bang that created the universe 13.8 billion years ago, says Harvard astrophysicist Abraham Loeb. [The Big Bang to Now in 10 Easy Steps]
For comparison, the earliest evidence of life on Earth dates from 3.8 billion years ago, about 700 million years after our planet formed.
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