Slashdot Mirror

← Back to Stories (view on slashdot.org)

Thrilling Discovery of Seven Earth-Sized Planets Orbiting Nearby Star (theguardian.com)

Posted by msmash on from the breakthrough dept.

At a press conference on Wednesday, NASA scientists announced that they have spotted seven Earth-sized planets orbiting closely around a small, ultra-cool star. The star is 39 light years away. From a report on The Guardian: It is the first time that so many Earth-sized planets have been found in orbit around the same star, an unexpected haul that suggests the Milky Way may be teeming with worlds that, in size and firmness underfoot at least, resemble our own rocky home. The planets closely circle a dwarf star named Trappist-1, which at 39 light years away makes the system a prime candidate to search for signs of life. Only marginally larger than Jupiter, the star shines with a feeble light about 2,000 times fainter than our sun. "The star is so small and cold that the seven planets are temperate, which means that they could have some liquid water and maybe life, by extension, on the surface," said Michael Gillon, an astrophysicist at the University of Liege in Belgium. [...] While the planets have Earth-like dimensions, their sizes ranging from 25 percent smaller to 10 percent larger, they could not be more different in other features. Most striking is how compact the planet's orbits are. Mercury, the innermost planet in the solar system, is six times farther from the sun than the outermost seventh planet is from Trappist-1.

7 of 273 comments (clear)

  1. Sterile and shattered. by Anonymous Coward · · Score: 2, Interesting

    The blast of sterilizing radiation at that distance, combined with being tidally locked and probably wracked with catastrophic earthquakes at that distance would make life on these planets an unlikely impossibility.

    1. Re:Sterile and shattered. by MightyMartian · · Score: 4, Interesting

      I think that greatly depends. Without a strong magnetic field, the Earth would look a lot like Mars, with much of its ancient primordial atmosphere blown away. I can imagine if one or more of those planets do indeed have a strong magnetic field, then I don't see how it is improbable that they could not harbor life. At the moment, we can't even declare with a high degree of assurance that Mars does not host life.

      --
      The world's burning. Moped Jesus spotted on I50. Details at 11.
    2. Re:Sterile and shattered. by MillionthMonkey · · Score: 5, Interesting

      One thing you're forgetting is that these stars have very low gravity, so when they throw flares they get a lot further out into space than they do on the sun. Typically the incident radiation will be low for the reasons you described, but when a planet orbits through a flare it gets zapped really hard. Meanwhile, orbiting the sun, we are so unaffected by flares that when we saw one, we thought it was the Russians jamming our radar.

      People who get excited about aliens living on planets orbiting dwarf stars are kidding themselves. These stars are a dime a dozen and make up more than 90% of all stars, their light is more strongly affected by planetary transits, and they tend not to gobble up their innermost planets when forming. It's no wonder we find exoplanets around them all the time. But there is nobody interesting living on any of them. You can really only trust type F and G stars with life. Larger stars explode so fast their planets haven't even had time to solidify, and smaller stars have to be hugged so closely that the planet is affected by the star's fickle weather patterns.

  2. Let's set up a telescope array on the moon now by presidenteloco · · Score: 4, Interesting

    No seriously, we should set up a very large synthetic aperture array of telescopes on the far side of the moon to look at these and similar promising exoplanets in high resolution and spectroscopically etc.

    Yes. I know the far side of the moon isn't always dark, but half the time it is, and is shaded from Earth's light and our EM emissions etc.

    --

    Where are we going and why are we in a handbasket?
  3. Re:Names for 7 planets orbiting a red dwarf star by Applehu+Akbar · · Score: 3, Interesting

    Relevant xkcd: http://xkcd.com/1253/

    I would rather see naming rights auctioned off to the highest bidder, with the proceeds to benefit space research. Let the human ego do some good.

  4. They forgot to mention X-Rays by little1973 · · Score: 4, Interesting

    Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1

    https://arxiv.org/abs/1605.015...

    --
    Government cannot make man richer, but it can make him poorer. - Ludwig von Mises
  5. Re:Names for 7 planets orbiting a red dwarf star by arth1 · · Score: 3, Interesting

    How about: Bashful, Doc, Dopey, Happy, Sleepy, Sneezy and Grumpy?

    That's appropriate because by definition, they are dwarf planets, even if bigger than Earth. There are only 8 "real" planets according to the rules makers. Nothing orbiting a different star can qualify, according to the hastily made rules designed to exclude Pluto. But you can call pretty much anything that doesn't qualify a dwarf planet.