Slashdot Mirror

← Back to Stories (view on slashdot.org)

First Earth-Sized Exoplanet May Have Been Found

Posted by kdawson on from the but-not-as-we-know-it dept.

Adam Korbitz writes "New Scientist is reporting the extrasolar planet MOA-2007-BLG-192Lb — whose discovery was announced just last summer — may actually be the first truly Earth-sized exoplanet to be identified. A new analysis suggests the planet weighs less than half the original estimate of 3.3 Earth masses; the new estimate pegs the planet's size at 1.4 Earth masses. The planet orbits a small red dwarf star, some 3,000 light-years from here, at an orbital distance of 0.62 astronomical units, about the same distance as Venus from our sun. One significance of the planet's discovery is that it points to the probable ubiquity of smaller terrestrial planets in somewhat Earth-like orbits around red dwarf stars, the oldest and most numerous stars in the galaxy. Here is a video report from the discoverers."

9 of 222 comments (clear)

  1. Re:GNAA by lorelorn · · Score: 5, Informative
    Not really. The detection methods currently used to find exoplanets mean that the larger and closer the planet is to its parent star, the easier it is for us to find.

    As our techniques become more sophisticated, we will be able to find more planets of a comparable size to our own. Those 335 can be thought of as the 'first wave' of discovered exoplanets. Large bodies close to their parent stars. These planets are interesting for what they can tell us about how solar systems can form.

    The next wave of discovered exoplanets will be smaller, say between the sizes of Venus and Neptune, and therefore far more interesting from the perspective of extrasolar life.

  2. Earth-sized != Earth-like by Anonymous Coward · · Score: 5, Interesting

    Just because it's an earth-sized planet doesn't mean it's Earth-like. Red dwarf stars are very small (no more than half the mass of the Sun). They don't put out much energy so the habitable zones are very small and very close to the planet. Being so close to the sun makes it likely that the planet would be tidally locked (same side always facing the sun) which isn't so good for life. Finally red dwarf stars often have high stellar variation (sometimes fry you, sometimes freeze you), also not so good for life.

    So exciting, but keep looking.....

    http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems

  3. So? by bradbury · · Score: 5, Interesting

    If you are familiar with the work of Charlie Lineweaver's group in AU, you would be aware that not only should Earth-like planets exist but that a significant number of them are older, and potentially more advanced than we are. This might then lead you to explore whether or not Matrioshka Brains (forms of civilizations significantly more advanced that our own exist.) And indirectly to an understanding that extremely advanced stellar civilizations have very different heat signatures (or detection signatures) from our own. Thus the detection of an earth-like planet is not that significant. The detection of a star going dark, signaling a civilization making a Kardashev-Type-I to a Kardashev-Type-II transition -- now that would be interesting.

    1. Re:So? by osu-neko · · Score: 5, Interesting

      If you are familiar with the work of Charlie Lineweaver's group in AU, you would be aware that not only should Earth-like planets exist but that a significant number of them are older, and potentially more advanced than we are.

      Familiarity with Lineweaver's work does not make one "aware" of that "fact", it merely makes one aware that some people have argued that that is the case. :p

      Lineweaver, Davis, and such have proposed a number of ideas which are intriguing, but it's all on very tiny and shaky foundations. Not saying they're wrong, but if they're reasonably close to right, that's more luck than anything, given the sample size of there real data it's all based on (e.g. estimating how many Earth-like planets develop life in their first billion years based on the one and only example we have of it happening).

      --
      "Convictions are more dangerous enemies of truth than lies."
    2. Re:So? by adavies42 · · Score: 5, Interesting

      i once saw this basic argument used to infer the existence of workable ftl. it goes something like this:

      1. conquering the whole galaxy (via generation ships or von neumann machines or whatever) takes only a few million years
      2. we're unlikely to be the absolute oldest civilization in the galaxy
      3. we do not appear to have been conquered
      4. the only feasible way to block conquest is a federation with a prime directive
      5. the only way to hold a federation together is ftl
      6. therefore ftl exists. qed.

      now obviously there are lots of holes in this, but i find it at least as compelling an answer to the fermi paradox as "they've all transcended"/"they're hiding in their dyson spheres".

      --
      Media that can be recorded and distributed can be recorded and distributed.
      -kfg
  4. Quick quiz by The+Bungi · · Score: 5, Interesting

    Since the strength of the gravitational field of a planet is a factor of its mass, and the gravitational pull on the surface is in direct relation to the distance from the center of the planet... could it not be possible to have a planet the size of say, Neptune, with a geological makeup similar to the Earth, that has a lower mass and therefore the acceleration at the surface is exactly 1g (as we understand it here on Earth). That is within the bounds of physics, is it not?

    Or maybe the effective gravity is stronger, but the planet spins faster. Faster days as well?

    The problem I guess would be the existence of a formation process that actually creates a planet with such a large surface but happens to be mostly rock instead of mostly gas (supposedly gas giants are "failed stars"). If it has a molten iron core, would it not collapse in on itself?

    Interesting, imagine a planet with the surface composition and atmosphere of Earth (and supposedly biomass) but 10 or more times the surface. That would be amazing.

  5. On the flip side... by interactive_civilian · · Score: 5, Insightful

    Earth might be broken in some ways, but it is (most likely) a lot better environment than anything else out there. Earth is a far better starting position than Mars or whatever and fixing what's broken here would be far more achievable than trying to build a viable human-sustaining ecosystem on some other planet.

    On the flip side, the spin-off technologies from making a sustainable habitat off planet would probably do wonders for improving the quality of life on planet. Everything from medical technology to air scrubbing and environmental cleanup, food and nutrition to understanding of local ecology and balancing it, energy technology to waste disposal and recycling, and probably much more.

    --
    "Empathise with stupidity, and you're halfway to thinking like an idiot." - Iain M. Banks
  6. Re:When can I pack my bags? by fractalspace · · Score: 5, Insightful

    Remember what we see is a 3000 year old image of the planet. It may not even exist today.

  7. Re:Ummm by PTBarnum · · Score: 5, Insightful

    I anticipate that someday science will advance to the point where ordering up your own private garden planet, and a fleet of intelligent and loyal robots to tend it for you, is considered routine. A wormhole network connecting your plant to a set of resource-rich sunless moons will be included at no extra charge.

    Everyone will have eternal life and health, lots of friends, and be allowed by their doctors to drink all the ice tea they want.

    But we still won't have flying cars.