Last month, an international team of astronomers announced a stunning discovery: a new planet orbiting the Sun’s nearest neighboring star, with the ability to support life. Using a technique called radial velocity search, the scientists detected tiny movements in the orbit of the star Proxima Centauri that could only be caused by an unknown planetary body.
Here’s what we know so far about about the new addition, dubbed Proxima Centauri b. It orbits its star–a red-dwarf–every 11. 2 days, putting it in the “habitable zone,” where temperatures are right for liquid water to exist on the surface. Its mass is at least 1.3 times that of Earth, indicating that it could be rocky (good luck finding life on a gas giant like Jupiter). And the big one: It’s just over four light-years away, making it the closest planet with habitability potential. Cue online tidal wave of excitement from astronomers and space agencies (oh, and Babylon 5 fan forums).
But there are a ton of things scientists don’t know about The Little Planet That Could (Or Could Not Be Like Earth). Like its radius, which will reveal whether or not it has a solid rocky surface. And where it came from-did it coalesce from space pebbles in the area or migrate from somewhere else? Or its magnetic field, which determines whether or not its surface hydration survived the high-energy radiation blasts of its star (Proxima b experiences X-ray fluxes 400 times that of Earth’s).
It’s that last one that’s the biggest factor for habitability. “I think we would all love to see what the planet’s atmosphere is made of,” said Daniel Apai, an astrobiologist at the University of Arizona and principal investigator for NASA’s Earths in Other Solar Systems research program. “It may have much more water than Earth or it may have essentially no water at all; it may have a very thick atmosphere driving a strong greenhouse effect or it may have no atmosphere. Before betting on its suitability for life I would want to know a bit more about the planet’s history.”
But to get answers to these kinds of questions, scientists will need to detect the atomosphere directly. Several “extremely” large telescope projects are underway that may be able to provide the imaging power necessary, something that would be impossible for planets farther away. Apai thinks with these types of images it will be possible to identify several key components of the Proxima b’s atmosphere–within the next decade.