A recently studied distant planet is helping NASA researchers perfect a method of examining distant atmospheres for signs of life.The reason this planet is so helpful? It's got great weather.
The so-called exo-planet, named HAT-P-11b, "appears to have clear skies," said Heather Knutson, a California Institute of Technology researcher involved in this study.
Clear skies allow an unobstructed view of what's creating a planet's atmosphere, she said. Clouds would block scientists from seeing what's there.
"We had a string of bad luck with the first set of planets that we looked at," she explained.
Those planets were all like San Francisco or Seattle: often cloudy. "So finding one that has clear skies is very exciting," she said.
Only about 1 in 5 planets examined were cloud free.
Using the Hubble telescope, Knutson and her team watched HAT-P-11b while it was backlit by its sun.
They scanned the halo created by the planet's atmosphere at different wavelengths and were able to determine that the planet has lots of hydrogen, helium and even some water vapor.
HAT-P-11b, which is about the size of Neptune, is one of the smaller planets this technique has been used on.
Knutson says this technique has been used on larger, Jupiter sized planets in the past, and on smaller Neptune sized ones, but HAT-P-11b is the first that had clear skies allowing for the best measurements.
While HAT-P-11b is still larger much than Earth, Knutson says perfecting this technique on larger planets is an important first step to applying it to study smaller planets in the future.
Especially of interest are Earth-sized planets with a rocky surface and liquid water. If such a planet were found to also have an atmosphere rich with oxygen, it could be home to alien life.
While the discovery of HAT-P-11b is exciting, it is unlikely that it harbors life, Knutson said. It's very hot, with no liquid water, and it doesn't have a rocky surface.
It is about 120 light years away, which is far for human spaceships, but is considered pretty close in galactic terms. "It's not that far away," Knutson remarked.