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Astronomers Claim Discovery of Earth-like Planet

Posted by CmdrTaco on from the that-would-be-a-rough-civ-map dept.

Raver32 writes "A team of astronomers announced they have discovered the smallest and potentially most Earth-like extrasolar planet yet. Five times as massive as Earth, it orbits a relatively cool star at a distance that would provide earthly temperatures as well, signaling the possibility of liquid water. 'The separation between the planet and its star is just right for having liquid water at its surface,' says astronomer and team spokesperson Stephane Udry of the Observatory of Geneva in Versoix, Switzerland. 'That's why we are a bit excited.' But researchers do not yet know if the planet contains water, if it is truly rocky like Earth, which might make it hospitable to life as we know it, or whether it is blanketed by a thick atmosphere. 'What we have,' Udry says, 'is the minimum mass of the planet and its separation" from its star.'"

5 of 225 comments (clear)

  1. Interesting find. by sneezinglion · · Score: 3, Interesting

    I wonder how long before we can verify an earth like extrasolar planet?

    As more of these are found we may be able to plug more data into drake's equation

    1. Re:Interesting find. by WibbleOnMars · · Score: 4, Interesting

      Since Drake's equation needs to know the proportions of stars with planets, it would require us to have known negative results as well as known positives in order for it to give any meaningful results.

      At the moment, we can say there are a few hundred planets, out of maybe a few thousand stars that we've scanned, but for the stars where we haven't found anything, we don't know for sure whether that's because there isn't anything there, or because we just aren't looking hard enough.

  2. Re:5x mass = 5x gravity by jayhawk88 · · Score: 3, Interesting

    Plus you can take into account all the other advantages life on Earth has had to make it possible:

    - In a solar system with a large gas giant, which helps keep catastrophic impacts with asteroids and comets from happening too often

    - Has a large satellite, which may help stabilize climate

    - Is in a quiet part of the galaxy, and is not too near other stars, avoiding interactions with other stars/gamma ray bursts/etc.

  3. What's the eccentricity of the orbit? by bersl2 · · Score: 3, Interesting

    That's kind of important, I would think.

  4. Re:5x mass = 5x gravity by doubletruncation · · Score: 3, Interesting
    As others have said, if the planet has the same average density as the earth, then its surface gravity would be 1.7 times greater. It's interesting, however, to see what how the density/surface gravity depends on composition.

    In this paper there are theoretical relations between planet radius and mass for a wide range of possible planet compositions. These are computed using equations of state that are largely determined from laboratory experiments.

    Anyway, for an Earth-like composition (~67% rock, 33% iron), a 5 M_earth planet would have a radius of ~1.5 R_earth yielding a surface gravity that is ~2.2 times greater than that of the Earth (such a planet is not incompressible, so the density is slightly higher for a greater mass).

    For a pure iron planet, the radius would be only 1.2 times that of the Earth and the surface gravity would be quite high (3.6 times the Earth's).

    For a pure rock planet, the radius would be 1.7 times that of the Earth and the surface gravity would be 1.75 times that of the Earth.

    For a pure "water-world" (say a scaled up version of some of the icy satellites orbiting the outer planets), the radius would be ~2.5 times that of the Earth and the surface gravity would be 0.8 times that of the Earth (i.e. less surface gravity than the Earth!).

    Point is there is a fairly significant range in possible radii and thus a significant range in the possible surface gravity.