On January 4, 2010, NASA announced Kepler's first modest discovery: five exoplanets -- "hot jupiters," with high masses, extreme temperatures, and large sizes (from about the size of Neptune to larger than Jupiter -- both of which are far larger than the planet we call home). So, nothing habitable. But since then, the industrious floating photometer has gone on to discover more than one orb in the habitable zone, along with a few tantalizing space oddities.
The beautiful blue-green ball you see here -- in a NASA artist's rendition, of course -- is Kepler-22b, the first planet Kepler confirmed (on December 5, 2011) as orbiting in a star's habitable zone.
The planet grabbed headlines as a potential doppelganger for Earth (despite it being two and a half times larger). But scientists aren't sure if it has a predominantly rocky, gaseous, or liquid composition. Still, Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington, said at the time of the discovery, "This is a major milestone on the road to finding Earth's twin."
And it presumably made a lot of people sit up and pay attention.
May 19, 2013 12:01 AM PDT
Photo by: NASA/Ames/JPL-Caltech
| Caption by: Edward Moyer
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