There’s An Earth-Like, Possibly Habitable, Planet 600 Light Years Away

The Kepler Space Telescope has been searching for planets outside our Solar System for some time now, but it hasn’t found a planet that could be habitable until now:

The search for Earth-like planets circling other stars is heating up, but the latest discovery is not too hot at all. It’s not too cold, either. Instead, the temperature on the newly announced planet Kepler-22b could be just right for life — about 72 degrees, a perfect spring day on Earth.

Spied by NASA’s Kepler space telescope, Kepler-22b marks the best candidate yet for a life-bearing world beyond our solar system, project scientists said Monday.

“If it has a surface, it ought to have a nice temperature,” said Kepler’s lead scientist, Bill Borucki, during a teleconference Monday.

“It’s right in the middle of the habitable zone,” said Natalie Batahla, a Kepler scientist, referring to the narrow, balmy band of space around any star where water can be liquid. “The other exciting thing is that it orbits a star very, very similar to our own sun.”

The actual temperature on Kepler-22b hinges on whether the planet has an atmosphere, which, like a blanket, would warm the surface. Even without an atmosphere, Borucki said, the planet would likely be warm enough to host liquid water on its surface.

If it has a surface.

At 2.4 times wider than Earth, the composition of Kepler-22b is a puzzle. It could be rocky, a “super-Earth” much like our planet but bigger. It might also be a water world covered with deep oceans, said Dimitar Sasselov, a Kepler scientist at the Harvard-Smithsonian Center for Astrophysics. Or it could be gaseous like Neptune or Uranus.

Determining the planet’s composition rests in part on measuring its mass — how heavy it is. The Kepler telescope is unable to make this measurement, but ground-based telescopes can by watching the planet tugging on its star. Telescopes in Hawaii and elsewhere will attempt these measurements when the star comes into view next summer, Borucki said.

Besides its balmy temperature, Kepler-22b shares other intriguing similarities with Earth. The planet’s home star, some 600 light years distant and near the constellation Cygnus, is “almost a solar twin,” Batahla said. That means the light hitting the planet’s surface would be almost the same color as the light hitting Earth. And Kepler-22b’s year is almost the same length as an Earth year: 290 days instead of 365.

Aside from Kepler 22-b, the Kepler mission has been pretty successful at tracking down evidence of planetary objects:

The announcement of Kepler-22b has amped up excitement among scientists searching for Earth-like planets orbiting sunlike stars, the goal of the $600 million Kepler mission, which launched into Earth orbit in 2009. This week, Kepler scientists are meeting at NASA’s Ames Research Center in California to review the mission’s successes.

They are legion. By staring at 150,000 stars, Kepler has found 2,326 “candidate planets.” Most are huge gas giants like Jupiter. But 207 of the candidates would be similar in size to Earth. Of those, 10 hold special interest — like Kepler-22b, they orbit their stars in the habitable zone. Follow-up observations are underway to determine whether these 10 candidates are true planets or false signals.

Said Batahla: “We are getting really close, we are really homing in on the true Earth-sized habitable planets.”

The more planets like this we find, the less likely the “we are alone” hypothesis would seem to be. Confirming the existence of life hundreds or thousands of light years away won’t be easy, and may not even be possible unless we detect radio signals indicating intelligence, but once you start finding planets that possess the conditions that make life possible it’s not that far a leap to the conclusion that some form of life must exist there.

Artists conception of Kepler 22-b via NASA

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Doug Mataconis
About Doug Mataconis
Doug Mataconis held a B.A. in Political Science from Rutgers University and J.D. from George Mason University School of Law. He joined the staff of OTB in May 2010 and contributed a staggering 16,483 posts before his retirement in January 2020. He passed far too young in July 2021.


  1. Hey Norm says:

    But now we know that we can travel faster than the speed of light…confirming the existence of other inhabitants will be much, much easier.

  2. Well, we don’t really know that yet. For one thing, that neutrino experiment is still disputed and needs to be replicated by other scientists in other locations before we go rewriting the last century of physics. For another, even if that proves to be true, its not at all clear it could ever be harnessed as a source of energy and/or travel.

  3. Rob in CT says:

    I find this stuff very cool. Though to be fair, the “habitable zone” is pretty wide and there are a bunch of assumptions required to conclude (rather than simply say there’s a small chance) that a planet is habitable (by life forms that roughly line up with what we know).

    The Warp Drive might as well be magic at this point. But then, any sufficiently advanced technology… you know the rest. Basically, I think that if we do ultimately figure out FTL travel, it’ll be long after we’re all dead.

    And cool as it would be, getting FTL ability presents its own dangers. So maybe it’s not a bad thing we don’t have it.

    Meanwhile: more investment in asteroid avoidance, please.

  4. Rob,

    Zefram Cochrane should have FTL figured out by the 5th of April, 2063

  5. Andre Kenji says:

    I think that NASA wants people to believe that they can find extraterrestrial life just to secure funding. Most people confuse the science of space exploration with science fiction. That´s bad.

  6. Franklin says:

    @Doug Mataconis: Heh, I think Hey Norm was joking. Especially since those neutrinos were barely faster than light, and we’re not neutrinos.

  7. Hey Norm says:

    At least Franklin got it…
    But hey…a nano-second here and a nano-second there…

  8. ponce says:

    Zefram Cochrane should have FTL figured out by the 5th of April, 2063

    It’s hard to accept I probably won’t even live to see the Moon colonized after all the hype of the 50s and 60s.

    Oh well.

  9. OzarkHillbilly says:

    The Nazca got FTL travel from their alien freinds over 1200 years ago. That is why they aren’t here anymore.

  10. Brett says:

    I really wish NASA wouldn’t rush to call every planet they find that’s in the habitable zone “earth-like”.

    Sure, it’s possible that this is a big rocky world with unusually low density (closer to Mars than Earth), but it’s more likely to be either a very small gas giant or a big “ocean planet” (with an ocean thousands of kilometers deep). The boundary between those gets pretty blurry anyways once you’re in the range of 8+ Earth masses.

  11. Joel says:

    It seems that we get at least one of these planets every year and then it goes nowhere. I’m not saying it isn’t possible this planet supports life, but as Brett said, scientists tend to jump the gun on these things.

  12. sam says:

    @Rob in CT:

    Basically, I think that if we do ultimately figure out FTL travel, it’ll be long after we’re all dead

    Maybe, but

    There was a young lady named Bright
    Who travelled in excess of the speed of light.
    She left one day in her relative way,
    And arrived the previous night.

    See ya yesterday, dude.

  13. Neil Hudelson says:

    @Hey Norm:
    Pretty soon we’ll have some microseconds? Then the sky’s the limit.

  14. tps says:

    They’ve got ideas on how to look for any intelligent life on other planets without listening for radio signals. Things like measuring the spectrum of a planet’s atmosphere for non-natural concentrations of gases. Also by looking for the lack of asteroids and/or comets since those could be used as off plnet resources.