Scientists have found a new Earth-like planet just 40 light-years away that could support alien life.
The planet is a notable discovery in the search for habitable worlds: It is thought to be slightly smaller and slightly hotter than Earth. Many planets outside our solar system, called exoplanets, tend to be much larger and hotter than our own Earth.
The newly discovered planet is called Gliese 12b, and researchers say that even if we can’t find out whether it hosts alien life, it will help us search for other worlds that might.
The planetoid orbits its host star every 12.8 days and is comparable in size to Venus, meaning it is slightly smaller than Earth.
The estimated surface temperature is 42°C, lower than most of the 5,000-odd exoplanets (planets outside the solar system) confirmed so far.
Astronomers suggest that Gliese 12 b is one of the few known planets on which humans could theoretically survive, but they’re still unsure what its atmosphere might look like, if it exists.
Getting an answer about what the atmosphere is like is vital because it will reveal whether the planet can maintain temperatures suitable for liquid water and possibly life to exist on its surface.
“We have found the closest, transiting, temperate, Earth-sized world ever located,” said Masayuki Kuzuhara, a project assistant professor at the Center for Astrobiology in Tokyo who led a research team with Akihiko Fukui.
“Although we don’t yet know whether it has an atmosphere, we think of it as an exo-Venus with similar size and star energy to our planetary neighbor in the solar system.”
Professor Thomas Wilson, a physicist from the University of Warwick, was involved in the discovery, using data from NASA’s satellites to confirm the existence of the planet and its characteristics such as its size, temperature and distance from Earth.
He said: “This is a really exciting discovery and will help our search for Earth-like planets.
“Unfortunately, this planet is too far away for us to experience it more closely. The light we see now is from 40 years ago; That’s how long it took to reach us on Earth.
“Exoplanets like Gliese 12 b are very few and far apart, so it’s very rare for us to be able to examine one this closely and learn about its atmosphere and temperature.”
Two teams, one in Tokyo, used NASA’s TESS (Transiting Exoplanet Survey Satellite) observations to aid their exploration.
The Sun’s equivalent of the planet, called Gliese 12, is a cool red dwarf located in the constellation Pisces.
The star is only 27% the size of the Sun and has about 60% of the Sun’s surface temperature.
Gliese 12 b is not the first Earth-like exoplanet to be discovered, but Nasa said there are only a handful of similar worlds that warrant a closer look.
It has been declared a potential target for further research by the US space agency’s £7.5bn James Webb Space Telescope.
The newly discovered planet could also be important because it could help reveal whether the majority of stars in the Milky Way galaxy host temperate planets that have atmospheres and are therefore habitable.
The distance between the planet and its star is only 7% of the distance between the Earth and the Sun, and the planet receives 1.6 times more energy from its star than the Earth receives from the Sun.
One of the important factors in maintaining an atmosphere is the storminess of its star.
Red dwarfs tend to be magnetically active, resulting in frequent and powerful X-ray bursts.
However, analysis by scientists conclude that Gliese 12 shows no signs of extreme behavior.
“Gliese 12 b represents one of the best targets for studying whether Earth-sized planets orbiting cool stars can maintain their atmospheres, a crucial step in advancing our understanding of the habitability of planets in our galaxy,” said PhD student Shishir Dholakia. Center for Astrophysics at the University of Southern Queensland, Australia.
He led a research team with PhD student Larissa Palethorpe at the University of Edinburgh and University College London (UCL).
Co-author Dr., also from UCL. Vincent Van Eylen said: “GJ12b is an incredibly exciting planet because it is the same size as Earth.
“Although GJ12b is about 15 times closer to its star than Earth is to our Sun, because it orbits a very small star, the temperature on the planet can be quite similar to that on Earth.
“This doesn’t guarantee that the planet is habitable, but it does make it a great place to start looking.
“Fortunately, this is also a very close star, so we will learn much more about the planet and its atmosphere in the coming years with telescopes like JWST.”
A paper led by researchers in Tokyo was published in The Astrophysical Journal Letters, and Dholakia and Palethorpe’s findings were published in the Monthly Notices of the Royal Astronomical Society.
Additional reporting by agencies