Humans could now be closer to finding a second home as astronomers have made a rare discovery: a new Earth-sized planet that could support human life.
If the planet has an atmosphere, the scientists think it could also hold water – and maybe, just maybe, even host alien life on its surface.
Published in the Monthly Notices of the Royal Astronomical Society, the new study describes the rocky exoplanet known as Gliese 12 b. It has the same surface temperature as the UK in the 2022 heatwave – a balmy 42ºC (107ºF) – making it, in theory, habitable.
While it’s still much higher than Earth’s typical surface temperature of 15º C (59º F), Gliese 12 b's climate is still considered unusually cold – it’s one of the chilliest of the 5,000 exoplanets confirmed so far.
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Gliese 12 b was discovered by an international team of scientists alongside NASA and ESA.
“This is a really exciting discovery and will help our research into planets similar to Earth across our Galaxy. Thrillingly, this planet is the closest Earth-sized and temperature planet we know,” one of the scientists, University of Warwick astrophysicist Dr Thomas Wilson, said.
“Planets like Gliese 12 b are very few and far between, so for us to be able to examine one this closely and learn about its atmosphere and temperature is very rare.”
Wilson and the team discovered the planet 40 light years away, in the constellation of Pisces orbiting a cool red dwarf star called Gliese 12. That’s the planet’s equivalent of our Sun, except Gliese 12 is only 27 per cent the size of ours and has 60 per cent its surface temperature.
The planet is similar in size to Earth (though slightly closer to Venus in size), and orbits its star every 12.8 days – a much shorter ‘year’ than our 365 days.
So what does ‘habitable’ actually mean? Being habitable means that it’s possible humans could survive on a planet. But the scientists still don’t know whether Gliese 12 b has an atmosphere, and what the atmosphere could be made of if it does.
Answering this question will be the researchers’ next step – and the result would be crucial in unlocking information about atmospheres in our own Solar System. In particular, the researchers want to find out why Earth’s and Venus’s are so different: Venus was made inhabitable when accelerated climate change destroyed the planet’s water sources.
Gliese 12 b’s atmosphere, if it has one, could explain why such changes happen – and predict what might happen to the Earth’s. And, if it does have an atmosphere, this would mean it can maintain its temperatures and allow the presence of liquid water.
The rare conditions of Gliese 12 b make it a good future candidate for the James Webb Space Telescope – and therefore, hopefully, answer some more questions.
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