There are several rocky, Earth-like planets orbiting nearby stars, such as out closest solar neighbour – Proxima Centauri. A rocky planet called Proxima b, which is 4.24 light years away from us, orbits Proxima Centauri, but researchers had argued that it is bombarded by too much radiation from its host star. Scientists believe the levels of radiation hitting Proxima b are 250 times higher than the doses we receive, meaning it is probably too high for life to evolve.
But a new argument put forward suggests there is strong evidence that life can begin to evolve in such extreme conditions, and that evidence is us.
Some four billion years ago, life on Earth began to emerge and at the same time the planet was a hot mess, receiving more radiation than Proxima b does today.
This means there is every chance that life is emerging on Proxima b, and other similar nearby rocky exoplanets – planets outside of our solar system – such as TRAPPIST-1e, Ross-128b and LHS-1140b.
All four of the planets were compared to Earth now and our planet in its past, and scientists discovered the levels of radiation the exoplanets receive is much lower than what Earth was bombarded with 3.9 billion years ago.
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However, all of these planets’ host stars are red dwarf stars, or M stars, which flair more erratically than our Sun, a yellow dwarf, or G star, releasing sporadic, but more intense, amounts of radiation.
For that reason, scientists Lisa Kaltenegger and Jack O’Malley-James, both of Cornell University’s Carl Sagan Institute. state they cannot be sure how this would effect the chances of the chances of life.
Nonetheless, the relatively nearby planets could still be the best chance of finding life away from Earth, according to the research published in Monthly Notices of the Royal Astronomical Society.
The duo write: "Given that the early Earth was inhabited, we show that UV radiation should not be a limiting factor for the habitability of planets orbiting M stars.
“Our closest neighbouring worlds remain intriguing targets for the search for life beyond our solar system."