In a study published in the Astronomical Journal, scientists say that planet GJ 1132b, which is 1.4 times the size of planet Earth and is 39 light-years away in the constellation Vela, is covered by a thick gaseous layer of Water, methane or a mixture of both substances, thus forming an atmosphere similar to that of our planet.
Discovering and identifying the composition of an atmosphere is a complex but very important step in the quest for life outside the Solar System. It is, however, unlikely that the GJ 1132b is inhabited, the surface temperature around 370 °C.
“As far as we know, the highest temperature life on Earth has on Earth is 120 °C”, said John Southworth, a Keele University researcher in Britain.
The discovery of the GJ 1132b was announced in 2015 and although it is similar in size to Earth, it orbits a smaller, colder and less bright star than the Sun.
With the help of an advanced telescope from the Southern European Observatory (ESO) in Chile, researchers have studied the planet, analyzing how it blocks the light from its star as it passes in front of it. “It makes the star less bright. It’s a good way to find planets”, Southworth said.
However, the different molecules present in the atmosphere of a planet (if they have one) absorb the light in different ways, which makes it possible to look for chemical signals of its composition.
The analyzes indicate that the GJ 1132b has an atmosphere of vapor and / or methane. “One possibility is that it’s a ‘water world'”, added Southworth.
Even though life forms are unlikely to survive the conditions of this planet, the discovery is exciting in the search for extraterrestrial life.
“We know that planets that orbit less massive stars may have atmospheres, and as there are so many of these features in the universe, that makes them more likely to have life”.
Marek Kukula, an astronomer at the Royal Observatory in Greenwich, UK, sees the discovery as a “good proof of concept” (a term used in scientific research to design a model that can prove theory).
“If technology can detect this atmosphere, then it can detect and study even more distant Earth-like atmospheres of the Earth in the future”, he said.