Days after scientists picked up a mysterious radio signal coming from the far corners of the cosmos, a team of scientists estimates there could be upwards of 300 million habitable planets in the Milky Way. Using data gathered by the Kepler spacecraft, a team of scientists led by NASA Ames' Steve Bryson have found that at least a third of the stars in our solar system that have a similar mass and brightness to that of our sun could have Earth-like planets in their respective "habitable zones."
In the years immediately following its launch, Kepler found 4,000 planets similar to that of Earth. Now accepted for publication in the Astronomical Journal, the report found the nearest planet is likely upwards of 20 light-years away. For the layman, that's roughly 117 trillion miles away. The latest report took 11 years to complete, using Kepler data from when the craft first launched until it stopped operating among the stars two years ago.
“It took 11 years from launch to publication, but this is it,” University of California, Santa Cruz astronmer Natalie Batalha told the New York Times. “This is the science result we’ve all been waiting for — the reason that Kepler was selected for flight in December 2001.”
As the study points out, the newly analyzed Kepler data suggest the galaxy may include nearly twice as many habitable planets as once thought from initial batches of data available in 2013. With any such findings, other scientists warned people to exercise caution and expect not to relocate to another solar system just quite yet.
“The Kepler Mission didn’t detect many (arguably, any) true Earth analogues, i.e. planets with the same radius as Earth AND orbiting at the same period, and hence receiving the same amount of light, AND orbiting sun-like stars," Harvard-Smithsonian astrophysicist David Charbonneau told the paper.
Batalha cautioned, “We don’t yet have any planet candidates that are exact analogues of the Earth in terms of size, orbit or star type.”