NASA Just Confirmed the Existence of 1,284 New Exoplanets

Kepler Discovered a Thousand More Exoplanets
NASA's planet-finding Kepler mission announced the discovery of more than a thousand more exoplanets Tuesday, making it the largest single new planet announcement in history. NASA/W. Stenzel

NASA officials on Tuesday afternoon confirmed the existence of 1,284 new planets, some of which are about the same size as Earth. This marks the single largest new-planet discovery ever, according to NASA.

Of these planets, all newly validated by NASA's planet-finding Kepler space telescope mission, 550 are considered candidates to be rocky planets like Earth, according to the announcement. Nine of them orbit "sun" stars in the habitable zone, meaning they are within a proper range of distance from the suns so their surface temperatures could allow liquid water to pool. Before today, only 12 exoplanets were considered part of that possibly habitable group; now, that number is 21.

NASA Kepler Exoplanet Discoveries
The histogram shows the number of planet discoveries by year for more than the past two decades of the exoplanet search. The blue bar shows previous non-Kepler planet discoveries, the light blue bar shows previous Kepler planet discoveries, the orange bar displays the 1,284 new validated planets. NASA Ames/W. Stenzel; Princeton University/T. Morton

To be confirmed as a verified planet, "candidate" planets are put through a careful vetting process. Before they're verified, the probability that they are planets must meet or exceed 99 percent. By last July, Kepler had identified 4,302 candidates. Of these, 1,284 were confirmed planets Tuesday, and an additional 1,327 "will require additional study," despite the probability that they are indeed planets being more likely than not. The remaining 707 are likely "some other astrophysical phenomena," according to NASA.

"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."