The “habitable zone” in astronomy-speak is the area around a star where liquid water could exist. It’s not, like, some cozy astronaut campground off in the cosmos. We know now for sure that about 600 light years away the planet known as Kepler-22b orbits in one, even coming awfully close to an orbit around its star matching an Earth-year. We also know that Kepler-22b is a bit over twice the size of Earth, making it the smallest planet we’ve found in a habitable zone.Of course, we think we’ve found a lot more than Kepler-22b — you might recall a whole lot of breathless announcing earlier this year — but this is the first one we’ve actually confirmed. Today’s NASA announcement also notes that the Kepler mission’s identified about 1,000 more habitable zone planet candidates.We have no idea what the planet is made of or what it’s surface is like. It could be made of gas or liquid. We find these things by watching stars for slight blips that might indicate a planet’s passed in front of it, not so much staring at them directly through a telescope. The Kepler mission — consisting of its space-bound namesake and a number of ground-based telescopes — needs three of these blips, or “transits,” to confirm the planet. We’re watching about 150,000 stars this way, and the numbers seem to indicate that not only are there a lot of planets hanging out in habitable zones, but that Earth-size planets are fairly common in our galaxy as well.“The tremendous growth in the number of Earth-size candidates tells us that we’re honing in on the planets Kepler was designed to detect: those that are not only Earth-size, but also are potentially habitable,” says Natalie Batalha, Kepler deputy science team lead at San Jose State University in California, in a NASA press release. “The more data we collect, the keener our eye for finding the smallest planets out at longer orbital periods.” Now, we only need to make some really huge leaps in our faster-than-light technology and maybe, just maybe, we’ll actually get a look at one of these planets before humankind kills itself.Reach this writer at michaelb@motherboard.tv.
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