NASA has announced a major breakthrough in its efforts to find planets outside the Solar System, leading them to reveal 1,284 new planets discovered by its Kepler space telescope. This is more than double the number it had found so far, which stood at 1,041.
The connotations are important. Essentially, it means there are many more planets of all sizes hiding in this planet-hunting telescope’s data, from Earth-sized worlds to gas giants. And it dramatically increases the number of worlds we have to study in our galaxy.
“This announcement more than doubles the number of confirmed planets from Kepler,” Ellen Stofan, chief scientist at NASA Headquarters in Washington, said in a statement. “This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth.”
This graph puts the number of new discoveries into context. NASA Ames/W. Stenzel; Princeton University/T. Morton
Kepler, which launched in 2009, has found thousands of planet candidates to date. But in order to confirm a detection is a planet, and not an anomaly, repeat observations are needed either by Kepler or other telescopes.
But a new analysis method, described in a study led by Timothy Morton from Princeton University in New Jersey, is a game changer. It allows astronomers to much more rapidly determine if an exoplanet is real or not. Applying this analysis to existing Kepler data, from its inaugural mission and not the newer K2 mission, turned up these 1,284 new planets. A further 1,327 were promising candidates, while 707 were ruled out as astrophysical phenomena.
"Planet candidates can be thought of like bread crumbs,” said Morton. “If you drop a few large crumbs on the floor, you can pick them up one by one. But, if you spill a whole bag of tiny crumbs, you're going to need a broom. This statistical analysis is our broom."
Above, some of the potentially habitable planets in the new batch of data. NASA Ames/N. Batalha and W. Stenzel
Among the planets found by Kepler so far are potentially habitable worlds like Kepler-452b and Kepler-186f, of which we know of about three dozen candidates, although we’re still yet to find a world exactly like Earth – one of the same size, orbiting a similar star to our Sun, in the same orbit.
But the latest batch of planets has turned up hundreds of new rocky worlds, including some – like a new world called Kepler-1229b (in the diagram above) – that are similar in size to Earth, and in the habitable zone of their star, that deserve further attention.
Kepler has been responsible for the vast majority of all exoplanets found to date, and this latest analysis technique further sets it apart as our primary planet-hunter. But upcoming telescopes like the Transiting Exoplanet Survey Satellite (TESS) could help astronomers find more. And instruments like the James Webb Space Telescope (JWST) in the future will let astronomers probe these worlds in greater detail than ever before.
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