Closest planet found outside solar system
An illustration of what the newly discovered planet near Alpha Centauri B could look like.
October 17th, 2012
01:15 PM ET

Closest planet found outside solar system

The hunt for planets like our own has come up with a striking discovery: There’s a planet about the same size as Earth in the nearby Alpha Centauri system, and it's the closest planet found outside our solar system.

“Close,” of course, is a relative term. No one’s getting there anytime soon: The newly found planet, which orbits a star called Alpha Centauri B, is about 4 light-years, or 23.5 trillion miles, away.

Based on its mass, the planet is a rocky world and not gaseous, said Xavier Dumusque of the Geneva Observatory in Switzerland. He and his colleagues published the findings in the journal Nature.

Scientists used an instrument called the High Accuracy Radial velocity Planet Searcher. HARPS, located at the European Southern Observatory's La Silla Observatory in Chile, searches for planets outside our solar system using a radial velocity method.

Here’s how that works: When a planet orbits a star, the star wobbles back and forth slightly because of the planet’s gravitational force. Scientists are looking at how fast the star is moving toward or away from Earth. They measure this through the wavelength of the light from the star, which gets shifted if there’s a planet present (the Doppler effect).

The newfound planet is unlikely to harbor life, or at least life as we know it, Dumusque said.

It’s located extremely close to its parent star – Earth has a 365-day orbit around our sun, and this other planet orbits its star in only three days. Temperatures on the surface could be in the area of 1300 degrees Fahrenheit, scientists estimate. Rather than solid, the surface is likely to be lava.

But there is hope for life in that neighborhood: Small-mass planets like the one orbiting Alpha Centauri B are usually not alone with their sun, Dumusque said. Often there are other planets in the system, farther away from the parent star.

The next step would be to continue monitoring the shifts in light from the star, looking for other planets. Time is of the essence, however: As Alpha Centauri B and another star, Alpha Centauri A, move closer to each other, finding any planets in the area will become more difficult. Proxima Centauri, the closest star to Earth besides the sun, may be related to this binary system.

When a planet similar to the Earth is detected, the next step is to start characterizing its atmosphere, looking for elements such as carbon and oxygen that are familiar to life on our own planet.

Finding those will be difficult with present technology, however, as HARPS has limitations. A high-tech tool is slated to come online in 2016 – it’s called ESPRESSO (Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations).

About 800 planets have been confirmed to exist outside our solar system, in addition to nearly 2,000 planet candidates found with the Kepler mission.

Before you get too excited about the planet orbiting Alpha Centauri B, keep in mind that it has not yet been confirmed by a second group of astronomers. But Dumusque says there's only a 1 in 10,000 chance that this is not a planet.

Sara Seager, professor of planetary science at Massachusetts Institute of Technology, was ecstatic about the news.

In order to study planets outside our solar system in detail, she said, these exoplanets need to be around the nearest stars. And Alpha Centauri has captured the human imagination for decades, she points out, even appearing in the film “Avatar.” Its proximity is a motivator for sending probes, and even astronauts, to a different star system.

“I think the reality of a planet around the nearest star and the promise of more is a game changer,” she said in an e-mail.

If other planets orbiting Alpha Centauri B are the same mass and size as the new planet, they will be hard to detect, she said. It would take eight more years of this same kind of data, using similar technology, to find a planet of similar mass in a “habitable zone” - in other words, at a distance from the star that would permit life.

“Hopefully Nature has provided a planet that is more easily detected,” she wrote.

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Filed under: In Space
soundoff (418 Responses)
  1. tom

    Got to this cnn article by bad luck. Never been to this place before. Let's see comment starts with dumb people saying let's go it's only 4 years. From there this just degenerates to nasty political comments. No wonder I don't read or watch cnn. Audience appears to have have reached the the dumb down point of Americans who went to the pathetic government schools.

    March 4, 2013 at 6:32 am |
  2. Diamond

    Is that the next planet we have to live on ?

    January 20, 2013 at 11:31 pm |
  3. Bob Knippel

    The wobble is associated with the planet and star orbiting a common center of mass, which , due to the obviously very different masses, places that point within the radius of the sun.

    December 30, 2012 at 11:38 am |
  4. Arnold

    I'm a long time researcher of physics, astronomy, asrology, Ets, Ufos, including Free energy, I'm not asking anyone to believe me, we are free to believe whatever we want to believe. This is simple open your mind and imagine the possibility that there are civilizations thousand or millions years far more ahead of our civilizations because according to my research the newly discovered planet Alpha Centauri is a livable for humans and animals like us, but the problem is for example human earth reach to travel that planet and the astronauts reported that they did not see any lifeforms there even though there is lifeforms living there, why because of their very highly advanced technologies they are capable of blinding and forming optical illusions protections for other beings like us to protect their own living things there. I,m waiting for any reply or comments for this or for more info you can e-mail me. Thanks Folks.

    December 30, 2012 at 9:18 am |
    • mcewenpe

      Arnold, as a researcher you should be able to provide evidence, not just make claims. You should be able to pose questions about your evidence, not just believe it blindly. You should be able to address your questions through experimentation (even thought experiments), not just take everything you say on faith or because it sounds cool.

      December 30, 2012 at 11:09 am |
      • Arnold

        Thanks for your comment, let me ask you question, How do you understand the logic of everything around you especially the words or group of words that you are reading ?
        I,m expecting your answers then I will give you my answer.

        December 31, 2012 at 10:31 pm |
  5. cdub2k

    1,300 degrees Fahrenheit? Orbits the sun every three days? 4 light years away?

    Sign me up

    October 31, 2012 at 3:43 pm |
  6. super_Nova1403

    it looks like the planet from avatar. derp... but really they make it look like those movies are just movies but half of the stuff you see is real. the government lies, they get paied to do that and we always fall for it. plus it'll take a LOT longer than four years to get there with super avanced engiens.

    October 19, 2012 at 11:42 am |
  7. Buck

    Since the 'powers that be' deleted my original post, here's another good article on 'space travel'.....

    October 18, 2012 at 1:49 pm |
  8. jarvis

    i had my math teacher do the calculations and the distance in miles it take light twentythree trillion four hundred sixtytwo billion seven hundred and eighty million... so this planet is inconciveably far (not 4 years)

    October 18, 2012 at 1:43 pm |
    • mdmann

      It would take 4 years if your were travelling at the speed of light. Maybe you are confused about something.

      October 18, 2012 at 7:07 pm |
  9. Sharon

    4 light years away and we can't even get there. Dang, I'm sick of living in the dark ages.

    October 18, 2012 at 1:15 pm |
  10. GoodfreyGreene

    I simply love stories like these. Every new planetary discovery fills my mind with wonder. I find one fact very encouraging. We are finding many similar systems. We've found two systems with diamond like plantes. We've found several red star systems with super earth size planets. We've found a vast number of stars being orbited by Jupiter sized planets. In other words, solar systems are not like snowflakes! They can be similar or the same. So there must be one out there just like ours. It's only a matter of time before we find it. I can't wait!

    October 18, 2012 at 12:58 pm |
  11. itoldyouso10

    You know, the mentioning of "Avatar" really does bring out a good point...why don't we call it Pandora?

    October 18, 2012 at 12:28 pm |
  12. Jim

    it is true. but if you go there, beware of Klingons...

    October 18, 2012 at 12:25 pm |
  13. Pete

    Distance is irrelevant. Humans are not as intelligent as we believe we are. We are self centered and arrogant and believe everything revolves around us. Why? A dog is an intelligent animal with emotions, ability to learn etc, but no matter how hard we try to teach them, they will never grasp the concept of...say...algebra. Our brains will never grasp some concepts either, i.e. size/distance/time issues. We are just not built that way unfortunately. I do not think we should give up exploring of course, as we are inherently curious beings. YouTube any astronaut...ANY of them. They've seen things that have travelled distances we cannot. Wormhole? Space/Time warp? They comprehend how that works...and unfortunately we have not. To make things more interesting, read the Bible in context of an alien creator instead of God/Jesus... It makes it far less metaphorical and more on a physical level. What religion on our planet does not believe our creator or proxy did not ascend from the sky? All of them depict gods from the sky from the beginning of society. They would not write down what they didn't see....

    October 18, 2012 at 12:20 pm |
    • mdmann

      I really don't get the point you are trying to make. At all.

      October 18, 2012 at 7:09 pm |
  14. Marc Parella

    23.5 trillion miles away? Hmm. Considering our national debt is almost 23 trillion dollars, you could take a cab to this planet for what our government owes.

    October 18, 2012 at 12:17 pm |
    • mdmann

      Nice way to inject politics into this. Why don't you go ahead and finish your thought here. Drop some names and lay some blame.

      Some of you just can't let that crap go, can you? It consumes your every waking moment.

      October 18, 2012 at 7:11 pm |
  15. doom hammer

    Imagine a crew or vessel with a cargo of dozens of humans arriving on a habitable planet and the future this would usher in for that crew alone and humanity in general. Worth a trillion bucks and half a lifetime voyage in my mind.

    October 18, 2012 at 12:14 pm |
  16. Marc Parella

    This will be Earth's next home. "Danger Will Robinson"

    October 18, 2012 at 12:11 pm |
  17. Brian

    "I'm sorry, Fry, but astronomers renamed Uranus in 2620 to end that stupid joke once and for all."

    October 18, 2012 at 12:07 pm |
    • Mike

      "What did they change it to?"


      October 18, 2012 at 12:23 pm |
  18. Pete

    Has anybody actually thought about how we humans have virtually developed all aspects of technology in ONLY the last 100 years of our existence? Humans have been here....say...6,000 years, but why do you think this technology is suddenly here relatively speaking in a blink of an eye? Do you think our little tiny brains just thought of it now but couldn't in the last 5,900 years? Think about it... Also, why do you think we do not visit the moon any longer? We were warned to stay off of it...

    October 18, 2012 at 11:36 am |
    • LivinginVA

      Sounds like you'd enjoy Eric Frank Russell's Sinister Barrier......

      October 18, 2012 at 11:41 am |
    • mdmann

      Warned to stay off the moon by whom? The Transformers?

      Again, what point are you trying to make?

      I'm not at all surprised that the majority of our technological advances have happened relatively recently. It takes technological advance to make technological advance. There are only certain advancements early humans could make because they were very limited in the tools they could use. As the toolset has been built, the pace of advancement has increased. Also, as a larger portion of the population can be involved in the process of making advancements, that also has an effect on the pace. These things are EASILY explained. You really need to become more familiar with Occam's Razor, because you seem to be the type of person who looks for outlandish explanations for things were very simple explanations are evident.

      Why have we not been back to the moon? Did we have a reason to go back to the moon? The first time we went was ostensibly to outshine the Russians. That was accomplished. There is no strong reason to go back there. We are exploring Mars for evidence that life once existed there. The only non-military reason I can think of for going back to the moon would be to set up a permanent base there as an experiment in living off the planet. These space agencies have only so much money to work with, and they have to prioritize what they use that on. I'm sure many people have wanted a permanent moon base, but there were other projects deemed more important. Again, a SIMPLE explanation. There is no need to invoke aliens giving us demands to never return to the Moon. This isn't an Arthur C. Clarke novel.

      October 18, 2012 at 7:22 pm |
  19. najib

    Before we go too far off we should check what is there on the other side of the Sun. There could be another world there too maintaining equilibrium of motion in relation to our planet earth with same or improved metabolic aspects to support life. And I think our predecessors are rounding up for our arrival there.

    October 18, 2012 at 11:31 am |
    • Kikaider

      Sorry, not possible.
      We can detect earth-sized planets light years away based on their gravitational effect on their sun, how would we NOT be able to do this in our own back yard?
      It would have been literally impossible to NOT notice such an object in the early days of astronomy.

      October 18, 2012 at 1:13 pm |
  20. Evenstar13

    Ok, so there is a planet four light years away. Where there is one there is likely to be another and perhaps this is where ET comes from. Four light years away with superior technology is much more acceptable than say ET coming from the other side of the galaxy.

    October 18, 2012 at 11:28 am |
  21. Realityblowz

    So if a dollar was a mile.....This planet would be roughly twice the distance than our debt?

    October 18, 2012 at 11:17 am |
    • mdmann

      Yet another political troll.

      October 18, 2012 at 7:23 pm |
  22. Buck

    Check out this 'alien planet' NASA recently discovered, and with a little more funding, we'll eventually make contact with some of our galactic neighbors, even if we have to 'stage' a contact.....

    October 18, 2012 at 11:06 am |
  23. lolol

    humans destroyed the earth, humans will destroy other planets.

    October 18, 2012 at 10:36 am |
    • Kikaider

      What planet are you posting from, then? Let me assure you, the Earth is very much in one piece.

      October 18, 2012 at 1:15 pm |
    • Diamond

      Yes and that is whey we need a planet and know how to get there.

      January 20, 2013 at 11:34 pm |
  24. mitchncincy

    What good is finding an apparent earth like planet if we lack the technology to get there? Don't get me wrong I'm a big fan of space exploration and I firmly believe we need to continue to invest resources in space exploration but in my humble opinion shouldn't we be focusing more on ways to visit these places as opposed to simply looking for something or somewhere we can't get even begin to get to? Just saying.

    October 18, 2012 at 10:03 am |
    • Evenstar13

      One step at a time. One first needs to know where to go.

      October 18, 2012 at 11:30 am |
      • mitchncincy

        Yea I know, it's not that I'm not fascinated or impressed by all the stuff we have learned by sending probes and rovers to other worlds. It's just that at 49, I feel my time is running out to witness mankind make the next big leap. If nothing else, I'd at least like to see us get to Mar's or even back to the moon again before my time here is up. :)

        October 18, 2012 at 12:56 pm |
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