Scientists: Oceans, clouds, rain possible on distant planet
A graphic shows surface temperature variations on Gliese 581d and how wind patterns would moderate the climate.
May 18th, 2011
10:57 AM ET

Scientists: Oceans, clouds, rain possible on distant planet

Astronomers in France say a rocky planet orbiting a star that's one of our closest galactic neighbors may have all the ingredients to make us earthlings feel right at home.

The planet Gliese 581d, orbiting the red dwarf star Gliese 581 about 20 light years from Earth, could support oceans, clouds and rainfall with a greenhouse effect that would moderate its temperatures, the team of scientists from the Institut Pierre Simon Laplace in Paris says in a study published this month in The Astrophysical Journal Letters.

If you're thinking  the Gliese 581 system and possibly habitable planets sound familiar, you're right. Just last year, scientists reported that another planet, Gliese 581g, was a prime candidate to support life.

More recent studies have cast doubt on whether Gliese 581g even exists, although one of the scientists who claimed its discovery, astronomer Steven Vogt of the University of California-Santa Cruz, has defended his work, according to a report on Space.com.

With the 581g debate in mind, the scientists in Paris decided to take another look at 581d, which they note is seven times the size of Earth. When it was discovered in 2007, 581d was thought not to be capable of sustaining life, because it has permanent day and night sides, with the night side too cold for living organisms, and it gets only a third as much energy from its star as Earth gets from the sun.

The Paris scientists used a new atmospheric simulation model to look at 581d. And here's what they found, according to a press release:

"With a dense carbon dioxide atmosphere - a likely scenario on such a large planet - the climate of Gliese 581d is not only stable against collapse, but warm enough to have oceans, clouds and rainfall."

The fact that 581d orbits a red dwarf star makes a big difference, they found.

On Earth, a phenomenon called Rayleigh scattering reflects heat from our sun in the form of blue light back into space. This helps keep Earth from overheating. But as the atmosphere on 581d is absorbing only red light, Rayleigh scattering doesn't come into play.

"This means that (light) can penetrate much deeper into the atmosphere, where it heats the planet effectively due to the greenhouse effect of the CO2 atmosphere," the scientists said in the press release.

Their model also showed "the daylight heating was efficiently redistributed across the planet by the atmosphere, preventing atmospheric collapse on the night side or at the poles," they said.

But don't pack up the spaceship just yet.

"While Gliese 581d may be habitable there are other possibilities; it could have kept some atmospheric hydrogen, like Uranus and Neptune, or the fierce wind from its star during its infancy could even have torn its atmosphere away entirely," the scientists said.

And even if you left now, in a current-technology spaceship, it would take 300,000 years to get to the Gliese system.

So there's plenty of time to figure it out. Or get Capt. James T. Kirk and the starship Enterprise to explore strange new worlds.

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Filed under: Space
soundoff (364 Responses)
  1. Hyram Tyre

    What a weird planet name, They might as well just name it Nibiru? I wonder if there are any life there?

    May 22, 2011 at 12:12 am | Report abuse |
  2. vrim

    That big rock is of no use, unless it's got some oil on it.

    May 22, 2011 at 12:14 am | Report abuse |
  3. ELH

    It is truly remarkable. The posts to nearly every article that mentions the possibility of life elsewhere in the universe or that discusses 'earth-like' planets always degenerates into arguments over and about religion or the existence of a supreme being. I wish the God folks would just go away, perhaps to Gliese 581g.

    May 22, 2011 at 12:32 am | Report abuse |
    • Rod C. Venger

      Actually, the idea of God and life elsewhere are not incompatible. The Bible is completely silent on the matter. In a week God made the Universe, earth and everything in it as we know it...or at least how it existed then. It says nothing about what he did after that. I'd be surprised, as a Christian, if I were to find out that God limited himself to only creating life here on Earth. Maybe he did. Maybe he didn't. What's God do in his time away from Human affairs? Only He knows.

      May 22, 2011 at 12:43 am | Report abuse |
  4. Rod C. Venger

    Their modes make too many assumptions, the biggest one, which the author concedes is that the planet may have a CO2 atmosphere..or may not have an atmosphere at all. That's not science. It's conjecture based best-scenario computer modeling. What about the other models they surely had to have run. The scenario where the atmosphere retained hydrogen. Or one where the atmosphere is methane...the most common type in our own solar system. These guys simply want to keep the money flowing by presenting the positive models. Intellectual dishonesty and scientific fraud is what it is. Welfare, for the exoplanet astronomers.

    May 22, 2011 at 12:36 am | Report abuse |
  5. jeff

    It is interesting at least that more MSM is putting this info out. We are most definitely not alone.

    May 22, 2011 at 1:07 am | Report abuse |
  6. Andrew

    Once again, apparently CNN forgot to place the actual link to the article being discussed. I really really wish CNN would stop doing that.

    May 22, 2011 at 1:11 am | Report abuse |
  7. taylor

    This article is OLD. There have been dozens of articles about this planet for several months. Keep up with current events CNN!!!

    May 22, 2011 at 1:34 am | Report abuse |
  8. Troy F.

    The entire world need LESS religion, think for yourself ! why is it evil to have evidence of other earthilike worlds ? Stupid.

    May 22, 2011 at 2:16 am | Report abuse |
  9. XRaDiiX

    Stop talking about the bible; its an insult to this discover and an insult to all scientists and explorers on the discovery of such profoundness. You must of forget they persecuted great Scientists back then for trying to prove the Sun was the middle of the solar system and the Earth was not flat.

    May 22, 2011 at 2:33 am | Report abuse |
  10. colonelingus

    In the beginning, Man created God.
    SIN.......... Self Induced Nonsense.

    May 22, 2011 at 2:34 am | Report abuse |
  11. Fonseka

    even IF there is such a planet, we won't be going there anytime soon.

    May 22, 2011 at 2:37 am | Report abuse |
  12. Josh Larson

    This story is about sapposed life on another planet, why are stupid religious people on here commenting about things in the bible??? lol Go worry bout judgement day even though it will never happen.

    May 22, 2011 at 3:11 am | Report abuse |
    • dred

      or we can read articles about scientists who think planets contain qualities that MAY support life but later argue whether that planet is actually there! LOL!

      There is allot of science that requires the same faith as religion.

      May 22, 2011 at 6:19 am | Report abuse |
    • Dave

      No Dred, science does not require faith like religion does. Science is proving your theory with the use of facts, which both sides here are trying to do,. At some point, one side or the other will come to be accepted based on the facts, not faith.

      May 22, 2011 at 7:08 am | Report abuse |
  13. Johnny Cage

    Well, it's quite obvious that as years go one, we gain resolution in how far and accurately we can view space around us, and its becoming more and more obvious that we are not the only place where life is possible. Multiply that possibility by 1,000,000,000,000,000 planets, and even 0.0001% chance becomes 100% chance that there is life elsewhere. People quoting the bible need to prepare for the day when science proves life exists elsewhere, that we are not the only planet in existence, and that perhaps god is man made after all as a way to control our own minds into a path we believe is righteous. We make our own decisions, and crete our own fantasies.

    May 22, 2011 at 3:19 am | Report abuse |
    • Jake

      And when that happens, religion will twist it around and still be the answer. This is how it has been for hundreds of years. It won't change

      May 22, 2011 at 4:44 am | Report abuse |
  14. Dr.Tong

    Anything that encourages the inhabitants of this planet to look up is good. We are too Earth bound. Mankind's destiny is the stars, or Mankind will go back to the caves, and eventually perish. I know, I know, some of you don't care. But I'm not responsible for your sickness.

    May 22, 2011 at 3:23 am | Report abuse |
  15. ed

    the miniature aliens are totally going to resist. eww

    May 22, 2011 at 3:39 am | Report abuse |
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