Waterworld Discovered in Space

… Well, everything is in space, but I mean outer space!

Observations by NASA’s Hubble Space Telescope have come up with a new class of planet, a waterworld enshrouded by a thick, steamy atmosphere. It’s smaller than Uranus but larger than Earth.

Zachory Berta of the Harvard-Smithsonian Center for Astrophysics (CfA) and colleagues made the observations of the planet GJ1214b.

“GJ1214b is like no planet we know of,” Berta said. “A huge fraction of its mass is made up of water.”

The ground-based MEarth Project, led by CfA’s David Charbonneau, discovered GJ1214b in 2009. This super-Earth is about 2.7 times Earth’s diameter and weighs almost seven times as much. It orbits a red-dwarf star every 38 hours at a distance of 1.3 million miles, giving it an estimated temperature of 450 degrees Fahrenheit.

Details here


  1. #1 Caleb Hall
    February 23, 2012

    Space is fascinating, and it is awesome that we are finding planets such as this one. They are getting closer and closer to finding life on another planet.

  2. #2 Michael Richmond
    February 23, 2012

    If you read their technical paper,


    you’ll see that their observations show a featureless transmission spectrum of the atmosphere. There is no evidence that the atmosphere is full of water; just that it has a relatively high mean molecular weight.

    I know of no evidence at all for the quoted statement, “A huge fraction of its mass is made up of water.” There is certainly no such evidence in the paper by Berta et al.

  3. #3 StevoR
    February 24, 2012

    … Well, everything is in space, but I mean outer space!

    Er, don’t you want to make that spacetime instead? ;-)

  4. #4 Johan
    February 24, 2012

    If you happen to read the ENTIRE technical paper (or just the conclusion) and not just the paragraph of abstract you WILL find the exact quotes:

    “Based on our observations,this atmosphere would likely consist of more than 50% water by mass”


    “…it suggests GJ1214b contains a substantial fraction of water throughout the interior of the planet…”

    That’s evidence enough for me!

  5. #5 Schenck
    February 24, 2012

    How is it 3x the size of Earth but 7x the mass if so much of it is low mass, low density water? Or is there an iron-y core larger than Earth’s core that makes up the difference? Guess that’s too much detail at this point.
    Absolutely amazing that we can even speculate on this sort of stuff. I remember being in an undergrad Earth Science class and the prof going off topic and talking about how ‘today there’s very few exoplanet, but you guys will be able to point out to your kids hundreds of them, with dozens that are very earth like and probably at least one that has life on it’. It’s pretty astounding how that’s quickly becoming true. And also, consider that an exoplanet used to be world news, now it barely makes a headline unless its a friggin planet made mostly out of water and steam!

  6. #6 Vince Whirlwind
    February 24, 2012

    What’s this “fahrenheit” business? Shouldn’t scientists use proper modern units of measurement?

    Personally, I’m a bit sick of hearing about these planets which have a ridiculously short orbital period.

    This doesn’t sound much like a “waterworld”. More of a “steamworld” with a bit of a try-hard press release.

  7. #7 Jerry Wills
    February 25, 2012

    450 degrees F? Sounds like another story I know of where NASA told us there is no atmosphere on Mars, yet they use a parachute to land the rovers and have plans for a winged surveyor for future missions. First Mars has no water or atmosphere, now it does… Wouldn’t any water on this newly discovered planet boil away?

  8. #8 Pete
    February 28, 2012

    To respond to Schenk: 2.7 times the diameter means 2.7 cubed (about 20) times the volume. Thus about 20 times the mass if this exoplanet were the same mean density as earth. Only 7 times the mass means it is consideralbly less dense, on average.
    To respond to Jerry Wills: water boils 1t 212 F (sorry, Vince, I mean 100 C) on earth at earth’s atmospheric pressure…which is a function of earth’s atmosphere and gravity. This exoplanet seems to have a denser atmosphere and higher gravity, thus water would have a higher boiling point. It seems from the limited info here that the water exists in both liqud and gas phases on GJ1214b.