MPIA

It stands to reason that our best hope of finding life as we know it on a planet beyond our solar system would require an atmosphere like the one that keeps us from receiving a lethal dose of radiation from the sun. For the first time, astronomers have spotted just such a life-preserving bubble on a planet close in size to Earth.

GJ 1132b is about 1.4 times as wide as our planet and has about 1.6 times the mass. It also appears it could have a steamy atmosphere rich in water, oxygen and methane.

Those are among the findings by a team centered at the Max Planck Institute for Astronomy in Germany and recently published in the Astronomical Journal.

This isn't the first atmosphere to be detected around an exoplanet, but it is the first to be spotted around a planet so close in size to our own. So far we've only detected them around gas giants and one really big super-Earth eight times larger than our home.

An atmosphere on a planet similar in size to ours may sound like a good sign when it comes to the possibility that life could survive on super-Earth GJ 1132b, located "only" 39 light-years away (about the same distance as the Trappist-1 system filled with Earth-like worlds), but there is one significant barrier.

According to scientists at the Harvard-Smithsonian Center for Astrophysics, anyone visiting GJ 1132b can expect temperatures around 450 degrees Fahrenheit (232 degrees Celsius).

"On cooler planets, oxygen could be a sign of alien life and habitability. But on a hot planet like GJ 1132b, it's a sign of the exact opposite -- a planet that's being baked and sterilized," Harvard astronomer Laura Schaefer said in a statement last year. Her team has done separate work modeling the planet's atmosphere.

This would likely make GJ 1132b more similar to Venus than to Earth, and rather inhospitable to life.

But the detection of an atmosphere on this planet could actually be good news for the potential of numerous other planets around the universe to host life. That's because it orbits an M dwarf star. These are one of the most common types of stars around, known for their habit of frequently shooting out flares and streams of particles that could literally blow away the atmospheres of nearby planets.

You could say that in the galactic neighborhood, M dwarfs are the cranky neighbors hosing down kids who get too close to their lawn.

But it appears the atmosphere of GJ 1132b has persisted over billions of years, lending a bit of cautious optimism to the notion that atmospheres and perhaps life could survive on planets like Proxima b and the Trappist-1 worlds that orbit those cantankerous M dwarfs.

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