While the newly discovered exoplanets and their six friends hold the exciting possibility of being capable of supporting life, scientists won’t know for sure for a while.
The Kepler Space Telescope made the discoveries, pushing the number of such exoplanets it has found to more than 1,000.
The punch list, according to astronomers with the Harvard-Smithsonian Center for Astrophysics (CfA), sounds good. They are not to close or too far from their star so that they might have water instead of ice or steam. They are about the right size, and they get a decent amount of sunlight.
And they also might have the kinds of surface that could bear life.
“Most of these planets have a good chance of being rocky, like Earth,” lead author Guillermo Torres of the CfA said in a release.
Which is a lot more hospitable that being a big ball of gasses.
“We don’t know for sure whether any of the planets in our sample are truly habitable,” second author David Kipping of the CfA said in a release.
“All we can say is that they’re promising candidates.”
Kepler-438b and Kepler-442b are the most similar to Earth of any known exoplanets to date.
And even if there was confirmation, Christine Pulliam with the CfA said teams are “still a couple of generations of telescope development away,” from even seeing them, much less visiting.
Kepler-438b is 470 light-years away and Kepler-442b is 1,100 light years away, according to CfA.
“That’s a little far away,” Caldwell said, “We need to get to Mars first.”
Still it’s very exciting just to discover them and to be closer to identifying a “second” Earth.
At a panel held last summer at NASA headquarters in Washington, astronomers said they were “very close in terms of technology and science to actually finding the other Earth.”
That’s due in part to the Kepler telescope. The planet-hunting Kepler probe, launched in 2009, finds planets by looking for dips in the brightness of a star as a planet transits, or crosses, in front of that star.
Pulliam said the team of scientists monitored data for more than 160,000 stars, which led them to the eight new planets.
The couple most like Earth, Kepler-438b and Kepler-442b, both orbit red dwarf stars, which are cooler and smaller than the Earth’s sun.
Kepler-438b’s diameter is 12% bigger than Earth and has a 70% chance of being rocky, which means the surface of the planet appears to be like Earth’s.
Kepler-442b is about one-third larger than Earth with a 60% chance of being rocky. Scientists give it a 97% chance of being in the habitable zone, but caution that the estimates aren’t certain.