Astronomers Find 7 Earth-Sized Planets Around A Nearby Star

Feb 22, 2017

By Nell Greenfieldboyce

A small, faint star relatively close by is home to seven Earth-sized planets with conditions that could be right for liquid water and maybe even life.

The discovery sets a record for both the most Earth-sized planets and the most potentially habitable planets ever discovered around a single star.

The strange planetary system is quite compact, with all of these worlds orbiting their star closer than Mercury orbits the sun, according to a newly published report in Nature.

“If you were on the surface of one of these planets, you would see the other ones as we see the moon, or a bit smaller,” says Michaël Gillon, an astronomer at the University of Liège in Belgium. “The view would be very impressive.”

The cool, reddish star is about 40 light-years away, in the constellation Aquarius. “It’s a very tiny star,” says Gillion, “10 times smaller than the sun.”

Until recently, no one was even looking for planets around so-called ultracool dwarf stars.

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14 comments on “Astronomers Find 7 Earth-Sized Planets Around A Nearby Star

  • Here is a BBC article on the same topic.

    http://www.bbc.co.uk/news/science-environment-39034050

    The planets were detected using Nasa’s Spitzer Space Telescope and several ground-based observatories are described in the journal Nature.

    . . . according to this BBC article, although the OP link says ..

    Already, initial observations have been made with the Hubble Space Telescope, he says, and the data is being analyzed. More observations with Hubble are planned to search for signs of water or methane.



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  • 3
    breezing says:

    As a matter of fact a Muslim believer – friend of mine- already commented that; seven earths are mentioned in Quran ! …any body to repel that claim ?



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  • breezing #3
    Feb 23, 2017 at 3:58 am

    seven earths are mentioned in Quran ! …any body to repel that claim ?

    I don’t know about repelling it, but if anyone ashed me which seven earths were known in the bronze-age, I would list:-

    sand, clay, peat, gravel, loess, silt and mud! 🙂



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  • breezing #3

    As a matter of fact a Muslim believer – friend of mine- already
    commented that; seven earths are mentioned in Quran ! …any body to
    repel that claim ?

    Only seven? I wonder why Allah didn’t know about all the others?

    Even just in the light of this report, we now know there are at least eight – our own, plus these 7 newly discovered others.

    But even this doesn’t reflect the actual situation, since this new discovery only relates to earth-sized planets newly discovered to be orbiting a single, not very distant star. But these are very far from being the only only Earth-like and/or potentially habitable habitable planets outside our own solar system:

    “In November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs in the Milky Way,[5][6] 11 billion of which may be orbiting Sun-like stars.[7]”

    Source: https://en.wikipedia.org/wiki/List_of_potentially_habitable_exoplanets

    And note: that’s just our own galaxy, the Milky Way. Who knows how many others there could be in the countless other galaxies in the universe? (Current estimates are that there are at least 100 billion of them.)

    So the current state of scientific knowledge isn’t that there are seven Earths. Merely that another seven have recently been discovered. If I’d written the Koran, I’d be feeling pretty sheepish right now.



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  • Just for clarity.

    When I wrote:

    (Current estimates are that there are at least 100 billion of them.)

    I was referring to other GALAXIES, not potentially Earth-like/habitable planets. And according to the above link, astronomers think there could be as many as 40 billion Earth-sized planets in our own galaxy alone.



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  • @OP – The discovery sets a record for both the most Earth-sized planets and the most potentially habitable planets ever discovered around a single star.

    I have cautioned before, that there is no reason to assume that Earth-sized planets are likely to be Earth-like planets.
    (Mars and Venus are two good examples of non-Earth-like planets!)



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  • Marco #6
    Feb 23, 2017 at 8:33 am

    Just for clarity.

    When I wrote:

    (Current estimates are that there are at least 100 billion of them.)

    I was referring to other GALAXIES, not potentially Earth-like/habitable planets. And according to the above link, astronomers think there could be as many as 40 billion Earth-sized planets in our own galaxy alone.

    Actually the current estimates are much more than 100 billion. The old figure of between 100 and 200 billion galaxies in the observable universe was derived from early Hubble data. By actually counting galaxies per unit volume of space in the Hubble Deep Field photos and extrapolating that over the size of the observable universe it is now thought that there are at least 2 trillion galaxies out there. An order of magnitude more than had been believed.



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  • Re my comment @#1 :-

    By Paul Rincon Science editor, BBC News website – BBC link
    In addition to the Spitzer observations, astronomers gathered data using Very Large Telescope in Chile, the Liverpool Telescope in La Palma, Spain, and others.

    While “others” are mentioned, there is no BBC reference to the Hubble Telescope, which is quoted in the NPR OP link.

    @ NPR link-
    Julien de Wit of MIT, one of the astronomers on the research team, says these planets have a “winning combination” of being temperate, Earth-size and ideally suited for follow-up observations with telescopes to analyze their atmospheres.

    Already, initial observations have been made with the Hubble Space Telescope, he says, and the data is being analyzed. More observations with Hubble are planned to search for signs of water or methane.

    Astronomers could get an even better sense after 2018, when the next-generation James Webb Space Telescope is expected to launch. It could provide an in-depth look at the atmospheres of these planets.

    As the original Nature Article is subscription access, this possible conflict of information remains unclear.



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  • Arkrid #9

    Thanks very much for that, Arkrid. I’d deliberately used the lowest of the estimates I’d found, since even that was quite high enough to make it unnecessary to leave myself open to possible accusations of having exaggerated in order to make my point. But all the same, I had no idea that the latest estimates were so very, very much higher. Fascinating and exciting stuff! Thanks again!



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  • “A […] star relatively close by”

    Well, relatively relative. 40 light-years distance means the following:

    The Helios 2 probe with its roughly 250,000 km/h / 160,000 mi/h was the fastest spacecraft until now. That’s about 1/4000 of c. With that velocity it’d take 160,000 years to go there.

    _Space … is big. Really big. You just won’t believe how vastly hugely mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist, but that’s just peanuts to space._
      – Douglas Adams, *The Hitchhiker’s Guide to the Galaxy*



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  • Geri #12
    Feb 27, 2017 at 8:39 am

    “A […] star relatively close by”

    Well, relatively relative. 40 light-years distance means the following:

    The Helios 2 probe with its roughly 250,000 km/h / 160,000 mi/h was the fastest spacecraft until now. That’s about 1/4000 of c. With that velocity it’d take 160,000 years to go there.

    Even using some of the proposed fusion drives, achieving a significant 10% to 12% fraction of light speed, (discussed earlier on this link), it would take about 400 years.

    https://www.richarddawkins.net/2017/02/what-it-would-take-to-reach-the-stars/

    However looking at the longer term, it might be possible over thousands of years to reach that system, by planet hopping across intervening star systems one at a time.

    In the very long term, who knows what star-systems may be near the Solar-System (or what is left of it), when the Andromeda Galaxy and the Milky Way eventually merge in about 4 billion years time, scattering stars and planets all over the place!



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  • Alan4discussion #8
    Feb 26, 2017 at 6:06 pm

    I have cautioned before,
    that there is no reason to assume that Earth-sized planets are likely to be Earth-like planets.

    Journalists and sensationalised headlines often make that mistake!

    http://www.bbc.co.uk/news/science-environment-39521344

    Atmosphere found around Earth-like planet GJ 1132b

    Scientists say they have detected an atmosphere around an Earth-like planet for the first time.

    They have studied a world known as GJ 1132b, which is 1.4-times the size of our planet and lies 39 light years away.

    Their observations suggest that the “super-Earth” is cloaked in a thick layer of gases that are either water or methane or a mixture of both.

    The study is published in the Astronomical Journal.

    Discovering an atmosphere, and characterising it, is an important step forward in the hunt for life beyond our Solar System.

    Butit is highly unlikely that this world is habitable: it has a surface temperature of 370C.

    Dr John Southworth, the lead researcher from Keele University, said: “To my knowledge the hottest temperature that life has been able to survive on Earth is 120C and that’s far cooler than this planet.”



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