Possibly Habitable Earth-Sized Planet Discovered

By Bill Andrews | April 17, 2014 1:00 pm
Kepler-186f, shown in this artist's concept, is the first Earth-sized planet discovered in its star's habitable zone. Credit: NASA Ames/SETI Institute/JPL-Caltech

Kepler-186f, shown in this artist’s concept, is the first Earth-sized planet discovered in its star’s habitable zone. Credit: NASA Ames/SETI Institute/JPL-Caltech

Exoplanets are fun and all, but those hot Jupiters and super Neptunes and such are kind of beside the point. Everyone knows the real search is for a planet like ours: rocky, smallish, and capable of hosting liquid water. And now scientists have found one, named Kepler-186f — an Earth-sized planet in its star’s habitable zone, the area where conditions aren’t too hot or too cold, but just right, for liquid water to be possible.

Planet Profile

The planet orbits a star about 500 light-years away called Kepler-186 and was discovered by the Kepler telescope (and then confirmed at the Keck and Gemini Observatories). The discovery technically includes four other exoplanets found around the star, but Kepler-186f is the only one in the habitable zone. Scientists found them all using the “transit method,” which is just basically looking at stars and waiting for planets to pass in front, dimming the star’s light a little bit.

From that little bit, they can determine a lot. Not only is it exciting that Kepler-186f is in the habitable zone, but researchers also learned that it’s very close to Earth-sized: about 1.1 times as wide. It also takes about 130 days to orbit its star, making its year just over a third of ours. Put that all together, and its likely Kepler-186f is a rocky world like Earth or Mars, since it’s not big enough to hold on to a huge atmosphere (like a gas giant). The results are published in this week’s edition of Science.

The Kepler-186 planetary system includes four planets besides Kepler-186f (all Earth-sized or smaller), and all orbit closer to their star than Mercury does to our own. Credit: NASA Ames/SETI Institute/JPL-Caltech

The Kepler-186 planetary system includes four planets besides Kepler-186f (all Earth-sized or smaller), and all orbit closer to their star than Mercury does to our own. Credit: NASA Ames/SETI Institute/JPL-Caltech

Not So Fast

Before we get too carried away, though, it’s important to remember the context of this discovery. For starters, Kepler-186f is a lot like Earth, but it’s not a true analog because it orbits a star very different from the sun. Kepler-186 is an M dwarf, a kind of star much smaller and dimmer than our own. M dwarfs are great for exoplanet hunters because they are super common (about 75 percent of the normal stars in our galaxy) and burn steadily for billions of years. But Kepler-186 is only about 47 percent as large as our sun, and Kepler-186f only receives about 32 percent of the solar energy that Earth gets. (It’s still in the habitable zone because its orbital distance is also a lot smaller, about 30 percent of Earth’s.)

Also, just because a planet is in the habitable zone doesn’t mean it has liquid water. As the paper’s abstract puts it, “If Kepler-186f has an Earth-like atmosphere and water at its surface, then some of this water is likely to be in liquid form.” That’s two big ifs: they’re possible, maybe even likely, but we don’t know the answers for sure. And, sadly, the system is too dim and distant for subsequent observations to tell us much more.

Still, the important thing is that we keep getting closer to finding an actual Earth-twin out there. Of some 1,800 exoplanets we know about, only about 20 orbit in their stars’ habitable zone, and only one (now) is Earth-sized and likely rocky to boot. But as those numbers keep going up, it might just be a matter of time before we find one that has everything we want on it — even, possibly, life.

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: exoplanets
  • John Majkrzak

    I think being located where it is makes Kepler-186f the planet getting pounded the most. Still it sounds like a good place to do mining and growing hallucinogenic mushrooms to keep the miners happy. Let’s go. By the time we get there in our multi-generational ship we will have the technology to defend the planet from asteroids anyway. It will be fun.

    • Saidur Rahman

      ever wonder to think how long will it take to get there if it takes 70,000 years(nearly) to reach our nearest star system,4ly away from SUN.
      i just calculated and got the answer 8.75 million years at todays speed.now another think to wonder about is if we are able to get there ever in future will the system even exist? Or if we send a probe there it would take 500 years to receive a signal from us and another 500 years to get a signal back to the earth from the probe.

      • Wilhelm Tomasi

        We need stargates.

      • Rob Brushia

        It will take precisely 500 years traveling at the speed of light.

        • bwana

          But zero time for the people on board the ship!

        • fatty

          You would have to put people on the ship and they would have to grow their own food and water and screw and make babies and in 25 generations they would arrive. I won’t be volunteering for that trip.

      • John Majkrzak

        Nobody would truly be goofy enough to embark on such a journey before the work on string theory is fully developed and settled. Eventually some young scientist will join the cadre of string theory researchers and not panic later. Have you ever wondered why those guys come and go? If you weren’t expecting to stumble upon Gods footprint and then you do – it could be a shorts filling experience. Once string theory gets hammered out then we fly a spaceship carrying a ready to assemble stargate thru a Stargate. The things we do for mushrooms.

        • Ronald L. Dula

          Actually, those guys come and go for a combination of two reasons. The first is it’s tough to get a job without being part of the string theory fan club. The reason they go is that string theory is more full of holes than intergalactic space. Or as a Nobel Prize winning physicist once put it, “It’s not even wrong!.”

      • fatty

        Yes, it would take 500 years to get a signal here and another 500 years to get it back. We don’t have anyway to make something go faster than in a vacuum free falling in space. You could put rockets on a falling meteor and the added weight would only slow it up. Hard to imagine. But there are people who actually believe that we can make a rocket go faster than the speed of light. It isn’t possible to visit these planets. Imagine you were in a rocket going 40,000 miles an hour through space. You would after a couple years hit so many meteors it would beat you to pieces. The only thing they could do is send a rocket in space with people and they would breed along the way and be able to grow their own food and make their own water and after 4 or 5 generations they might get somewhere.

      • fatty

        Imagine they go and come back and there are hooked nose people there ruling the whites and the blacks cause a lot of trouble and they would come back and lie and suppress that news.

    • fatty

      You believe with all the planets that would have to be between us and that planet and are we to believe they have a way to see what is on the other side of a planet? I bet you if our Sun was that far away it would be nothing more than a faint blur. Let alone a planet. Planets only give off a little light from a nearby star. I mean look at our planets in our solar system. Do they shine super bright. I say with all the planets and space dust they can not make out anything beyond 40 or 50 light years away. So they offer funding of millions to look for stuff and sure enough they are going to find something. Then they get the credit. I mean the biggest star is like 1,000 times bigger than our Sun. Can you see it with the naked eye? Then how can they detect a planet 10,000 times smaller than those bright stars 500 light years away. That is 186,000 miles a second for 500 years. You are somewhere around 5 quadrillion miles. Each quadrillion is 1,000 trillion. I think when you figure the enormous amount of space. You can pretty much figure this stuff is pure nonsense.

  • Oladele Ayuba

    but what is the point exactly?

    • Malia Obama

      To boldly go, duh.

    • The Doctor

      What is the point of NOT?

    • bwana

      Wouldn’t it be nice to have a 2nd, 3rd or more colonies of humans in the galaxy/universe just in case the Earth goes poof!?

    • Jexiah8bit

      That one day, the Earth will die. Either by our hands or its own. And exploring other solar systems is just the first step before traveling to them when the day finally comes that such a thing is made possible. It will have to be made possible, if the human race plans on living beyond the time of this planet. Even IF we somehow managed to survive ourselves, and even IF we colonized moons like Europa or Ganymede as the Sun started to go Red Giant billions of years from now, we will still eventually have to leave this solar system. Yeah that’s a hell of a long time from now, but I seriously doubt we will survive to then anyways if we haven’t colonized other worlds. We will be wiped out eventually if all we are is this one planet.

      • Oladele Ayuba

        ok so maybe we harvest sperms and eggs in a cryogenic chamber and blast them off 500 million light years… Yeah right

        • Jexiah8bit

          You can’t judge future technology based on current conditions. And nothing escapes entropy or the natural order of the universe, but we certainly have a greater chance of surpassing the Earth than most organic life forms on this planet.

  • Ali Zeeshan

    I think The Idea of Wrap drive can be achieved within 50 years, If proper work done on it.

    • John Majkrzak

      All things are relative. Everything in space resonates in harmony with it’s neighbor. When a ship travels thru space using a warp bubble the harmonics between the ship and its surrounding space is lost. If unprepared for that event then the unintended consequence is you can go but you can’t touch. It is more complicated than just building an FTL drive.

      • dude

        It is immposible for matter to go faster than the speed of light

        • John Majkrzak

          Dude, the world is flat.

          • teknowh0re

            Negative, but the universe may be a 2d holographic surface upon which the 3d information we percieve lays

          • John Majkrzak

            Perceptions are given through a lens. One potential trouble is that the focus control often seems out of our own reach.

          • teknowh0re

            It seems to me that you may share some of the almost untouchable ideas and conclusions I’ve come to recently. Myself and many others im sure. Unfortunately I lack the ability to express them in a way most people can understand. Everything that is being discovered about the nature of the universe makes total sense, and the picture is becoming clearer every year.

    • Emkay

      Wrap it up! I’ll take it….

  • Wade Carmen

    Donald Trump already bought it!

    • Emkay

      great.. now he will stiff all his creditors again by going bankrupt for the fifth time…..

  • Raylan C Jennings

    what I find so amusing is that we base all life on what we think life should be.. ie carbon based like what is here on earth..who is to say a different kind of life hasn’t form on Jupiter or any other planet..why are we so restrictive and narrow minded?

  • Vernon Cunningham

    our own imagination will create the way and means of getting to other stars. Notice that when enough people have a concept, then that becomes part of our reality.

    • bwana

      Maybe at some point our “imagination” will actually do the travelling?

      • teknowh0re

        Like remote viewing? I always told everyone when I was 10 that one day, all of humanity would exist on a computer chip the size of a postage stamp. Consciousness would be uploaded for the purpose of immortality.

        • bwana

          “Remote viewing” pretty much defines it. It takes infinite energy to accelerate matter to the speed of light, so the best option (at least envisioned at present) would be to “send” humanity to distant places using an energy data stream / waveform.

          • teknowh0re

            Exactly. Moving matter faster than light (our only hope of reaching even close stars) is pretty much not gonna happen. Ever. The illusionary nature of our cosmos, and our inability to view things outside our planet in ANY WAY other than our humanly biased way, will keep us from doing so. That’s just me though I’m NO cosmologist! =P

          • fatty

            The fastest anything moves in space in a vacuum is 40,000 miles an hour.This means you could put rockets on it and it would slow it down. Someone said they can build things that can travel faster then the speed of light. I would like to see it hold together. Personally I think the whole space program most of the money spent on it went into the pockets of the bastards who lied and I don’t think they went to the moon. I don’t think they had the technology back then.

    • Emkay

      the concept was affordable health care for everyone, the reality is Obummercare….

    • teknowh0re

      Some claim that thinking it makes it real.

      • bwana

        Observing it makes it real. Until the observation occurs everything is incoherent…

  • joe_public1

    500 LIGHT YEARS…. think we can make it ??

  • Jexiah8bit

    500 lights years is a long way, but considering that the Milky Way is 100,000 lights years long and its 27,000 lights years to galactic bulge from us, I think this system still counts as being in our neck of the woods.

  • fatty

    It’s too hard for me to comprehend something 500 light years away when there must be millions of planets blocking that planet. I think it is bogus and they say that crap, because they get funded to look for crap. So they know a planet is 500 light years away. I don’t know how many trillions of miles that is, but they wouldn’t know if it was twice the size or 10 times the size. For one thing you can’t hardly pick up the light of a star that far. How could a planet be illuminated enough trillions of miles to be able to be seen. I say they are lying and can’t see anything that far away. There would be so much dust and space junk between the planet and us that you couldn’t detect anything, but a blur.

    • Karl Meabrod

      Nobody said they saw the light reflected off the planet; what they saw was the light diminish from the star.
      By observing the amount of dimming and the frequency, the size and orbit are calculated.
      By observing the light/radio frequency spectrum, the minerals present are determined.
      Basics, that have been in use for decades.

    • teknowh0re

      Also, our ever advancing telescopes ARE able to pick up light that the human eye never could. Have you ever looked into how telescopes work? I mean the giant observatory ones.

  • ConnerSeth

    Thing is earth is going to eventually die by the hands of our sun, and this lifestyle we have is unsustainable. The earth will be around long after the humans who currently inhabit it. As the great carlin said “the planet isn’t going anywhere, the people are fucked” we’re only shortening our own lifespan here, but eventually life here will end. We must look far past our own generation and move to the stars if humanity wishes to thrive past our own planets solar systems lifespan.

    • teknowh0re

      We have several billion years before that happens.


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