Um… That "Goldilocks" Exoplanet May Not Exist

By Jennifer Welsh | October 12, 2010 5:44 pm

Gliesewhut2A group of Swiss astronomers announced yesterday at the International Astronomical Union’s annual meeting in Turin, Italy, that they couldn’t detect the “goldilocks” exoplanet found by U.S. researchers a few weeks ago. That news of that planet, dubbed Gliese 581g, generated much excitement, since researchers said it was only three times the size of Earth, and it appeared to lie in the habitable zone where liquid water could exist on the surface.

It didn’t take long for some cold water to be thrown on the astronomical community and the space-loving public. Presenter Francesco Pepe and his colleagues claim that it will be years before the data is clear enough to see such a planet.

“We do not see any evidence for a fifth planet … as announced by Vogt et al.,” Pepe wrote Science in an e-mail from the meeting. On the other hand, “we can’t prove there is no fifth planet.” No one yet has the required precision in their observations to prove the absence of such a small exoplanet, he notes. [ScienceNOW].

Such small planets are very hard to find. Astronomers discover these planets by calculating how they interact with the star they orbit, making it wiggle ever so slightly. The American team that identified the planet a few weeks ago saw the wiggles when analyzing a combination of two sets of data.

Astronomer Paul Butler, a member of the U.S. team who is at the Carnegie Institution for Science in Washington, D.C., says he can’t comment on the Swiss work because he wasn’t at the meeting and the data are unpublished. He notes, however, that more observations will likely be needed to solidify the existence of Gliese 581g. “I would expect that on the time scale of a year or two this should be settled.” [ScienceNOW].

There will be more information available when the Swiss team releases its data and methods, but for now you might want to unpack your bags.

Related content:
Bad Astronomy: Possible earthlike planet found in the Goldilocks zone of a nearby star!
Discoblog: So, How Long Would It Take to Travel to That Exciting New Exoplanet?
80beats: New Telescope Could Reveal a Milky Way Packed With Habitable Planets
Bad Astronomy: HUGE NEWS: first possibly Earthlike extrasolar planet found!
80beats: Don’t Pack Your Bags Yet—New Planet-Finder Hobbled by Electronic Glitch

Image: NSF

  • Michael Wilson

    There’s a Star Trek TNG Episode which explains this perfectly:

  • B

    The speculation was good while it lasted.
    But searching for goldilocks exoplanets through alice-in-wonderland techniques has never been a reliable prospect. These techniques include apparatus which rely on line-of-sight assumptions. It was a hopeless attempt from the beginning. Only reliable data based on direct optical observation is acceptable. Current optical telescope technology is capable of imaging binary stellar objects such as those detected by ESO. The Hubble Space Telescope should be capable of imaging Earth analog terrestrial exoplanets within 100 LY.
    New generation ground based telescopes such as the Thirty Meter Telescope and E-ELT will be needed to image relatively near stellar systems for Earth-like exoplanets. It may be asserted that most stellar systems have a company of terrestrial and gas giant planets.
    Formation of an Earth-like exoplanet appears to be a self propagating process dependent on factors such as metal content of stellar nebula and rotational velocity of star.

  • Colm Ryan

    While apparently disappointing, this is a tremendous example of science in action and a great example of the power of the scientific method. One group announces a result, the other group probe the data and find insufficient evidence. There are no holy grails or claims that are “above criticism”.

  • Daviticus

    At least not this time!

  • Jennifer Welsh

    Hey all,

    Thanks for reading and leaving your comments. I completely agree with @Colm Ryan!


  • Messier Tidy Upper

    Durnnit! :-(

    PS. @ Colm Ryan : I guess you’re right – but still disappointing in that we find the planet doesn’t exist after all.

    On the bright side at least we hadn’t yet launched a spaceprobe to it .. with people aboard.

    Plus the Gliese 581 system still remains one of the most fascinating and promising we’ve found so far even without that “goldilocks planet.”

  • amphiox

    “but still disappointing in that we find the planet doesn’t exist after all.”

    This doesn’t actually say that, only that the planet claimed by the other group was not confirmed (and this is not even published yet). Presumably something has to account for the discrepancy in results but which interpretation of the data is the more likely to be correct? When the Swiss team’s data is published I would expect that there will be some response from the American team. Who knows, maybe it will turn out the Swiss data is in error and the original claim is correct? Or maybe not.

    Time for more science!

  • itcy head

    What if the said new planet was there but it actually was a space ship so it’s not where they thought it should be any more??? Is that not possible at all?

  • Jennifer Welsh

    @itcy head, that would be one HUGE spaceship. Much MUCH bigger than the Death Star.

    Also both sets of readings were taken over the time span of years, some overlapping years even.


  • Messier Tidy Upper

    @7. amphiox :

    Who knows, maybe it will turn out the Swiss data is in error and the original claim is correct?

    Yeah I sure hope so! Thanks for that. :-)

    @9. Jennifer Welsh : Or could it be that the spaceship is travelling really fast (ie. a significent percentage of lightspeed) and thus appear more massive due to relativity? Not that that’s likely I know, but theoretically .. 😉

  • Kim S.

    Poster “B”, you’re wrong. Indirect measurement techniques may not in always be completely effective or accurate, but they do provide valuable data.

  • David S

    never mind, what I wrote was wrong.

  • Hollister UK

    groot artikel, bedankt voor de goede informatie, zal ik zeker delen in dit artikel aan mijn facebook pagina. keep up the good work.

  • abercrombie Milano

    I am excited about learning way more than what I have already taught myself. Thank you!


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