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Planet Mercury Has Shrunk More Than Thought

Posted by samzenpus on from the getting-small dept.

sciencehabit writes "Measuring just 4880 kilometers across, Mercury is a small world. The planet became slightly smaller as its interior cooled, which caused Mercury to shrink, buckling its surface and creating numerous cliffs and ridges. Now, after studying 5934 of these features, researchers report online today in Nature Geoscience that Mercury's contraction was much greater than previously thought: During the past 4 billion years, the planet's diameter decreased by 7 to 14 kilometers. The greater estimate of shrinkage accords with models that predict how much a rocky planet should contract as its interior cools; the new work may also lend insight into the evolution of extrasolar planets that, like Mercury and unlike Earth, lack any moving continents."

31 of 58 comments (clear)

  1. Someone left it in the dryer too long.. by toonces33 · · Score: 5, Funny

    Easy mistake to make.

    1. Re:Someone left it in the dryer too long.. by gargleblast · · Score: 1

      This will soon be the text of a new motivational poster: Mercury: Think. Or Shrink.

    2. Re:Someone left it in the dryer too long.. by Dragonslicer · · Score: 1

      So can we look forward to pre-shrunk planets?

  2. Shrinkage sucks. by Anonymous Coward · · Score: 3, Funny

    It's the girth, not the length that matters.

  3. Shrinkage by Tippler · · Score: 3, Funny

    The shrinkage of a body in response to cooling was experimentally derived by Dr. Costanza in the 90's.

    1. Re:Shrinkage by banda · · Score: 1

      ...like a frightened turtle

    2. Re:Shrinkage by ArcadeMan · · Score: 1

      Unfortunately, specialists such as Dr. Benes are not aware of all the research done in the field of shrinkage and continue to publish papers that are crucially missing this important information.

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    3. Re:Shrinkage by ArcadeMan · · Score: 2

      It's only common knowledge if you are male. Some females, however, did learn about shrinkage from a TV show called "Seinfeld".

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      Get free satoshi (Bitcoin) and Dogecoins
  4. Laugh by koan · · Score: 1

    Mercury is trying to tell all the other planets it's shrinkage but they know better.

    Obligatory penis joke aside, I'm surprised to hear it has "cooled" with it's greatest distance from the Sun being a mere 69,816,900 km.

    --
    "If any question why we died, Tell them because our fathers lied."
    1. Re:Laugh by Shakrai · · Score: 5, Informative

      I'm surprised to hear it has "cooled" with it's greatest distance from the Sun being a mere 69,816,900 km.

      The dark side of Mercury is a balmy -280F. Hard to retain any meaningful amount of heat when you have no atmosphere. :)

      --
      I want peace on earth and goodwill toward man.
      We are the United States Government! We don't do that sort of thing.
    2. Re:Laugh by Anonymous Coward · · Score: 1

      I would think the lack of atmosphere would prevent losses rather then insulate because a vacuum provides the best thermal insulation. If you look into building space craft you'll see removing heat is one of the primary challenges along with balancing the heat from the sun side and the shadow side. The reason why the shadow side of Mercury is freezing cold is because it barely rotates around it's axis it's day is equal to 58+ days on earth. It has plenty of time to lose heat due through radiation. Also it only rotates 1.5 times during an orbit of the sun....

    3. Re:Laugh by asylumx · · Score: 2

      I think you're talking out of Uranus.

    4. Re:Laugh by Anonymous Coward · · Score: 2, Informative

      Lets turn this around, how would an atmosphere promote loss? Where does that heat go? It still has to deal with vacuum insulation, just now a few kilometers higher than before. You can have evaporative cooling of some sort, where heat blows off part of the atmosphere, but then it wouldn't last very long without a source on the surface. Otherwise, it would help trap heat, which still has to go into the vacuum of space to fully leave the planet.

  5. Re:Whoa, tiny planet!! by HussamAl-Tayeb · · Score: 3, Informative

    nope, decreased by 14km (not TO 14km). It i still around twice the size of pluto.

  6. Mercury may be shrinking... by Anonymous Coward · · Score: 1

    ...but Uranus is expanding!

  7. Of course by Culture20 · · Score: 2

    Space is cold!

  8. Re:Whoa, tiny planet!! by sidyan · · Score: 4, Informative

    Mercury's diameter is 2.11 times that of 134340 Pluto, but its mass is 25.3 that of the puny dwarf planet.

    Discounting metallic hydrogen on Jupiter and Saturn, Mercury's definately the most Metal planet in the solar system.

  9. Re:Neil deGrasse Tyson called by Ferrofluid · · Score: 1

    You're thinking of Pluto.

  10. Re:Whoa, tiny planet!! by EvilSS · · Score: 1

    nope, decreased by 14km (not TO 14km). It i still around twice the size of pluto.

    So it's safe from being plutoed by NDT .... for now.

    --
    I browse on +1 so AC's need not respond, I won't see it.
  11. warning: bad pun inbound by gman003 · · Score: 1

    Ball-shrivelingly cold, as it turns out.

  12. Re:Neil deGrasse Tyson called by Anonymous Coward · · Score: 1

    You're thinking of Pluto.

    No, Uranus.

  13. Re:Whoa, tiny planet!! by mjwx · · Score: 1

    Mercury's diameter is 2.11 times that of 134340 Pluto, but its mass is 25.3 that of the puny dwarf planet.

    Discounting metallic hydrogen on Jupiter and Saturn, Mercury's definately the most Metal planet in the solar system.

    Of course it would be, you don't ever hear of a metal band with some pansy ass name like Jupiter.

    --
    Calling someone a "hater" only means you can not rationally rebut their argument.
  14. saw this one coming? by slashmydots · · Score: 1

    In other news, your mother's diameter has expanded by 2km.

  15. Re:Whoa, tiny planet!! by operagost · · Score: 1

    Thanks, Dr. Tyson, but we don't need Pluto's minor planet designation any more than we need Ceres'. It's pretty friggin' famous.

    --

    Gamingmuseum.com: Give your 3D accelerator a rest.
  16. ... but IS IT STILL A PLANET? by Arancaytar · · Score: 1

    That's the important question.

    We don't want a repeat of the Pluto incident. The solar system is already 11% gone, who knows how much we'll lose.

  17. Re:Whoa, tiny planet!! by mister_playboy · · Score: 1

    Of course it would be, you don't ever hear of a metal band with some pansy ass name like Jupiter.

    Heh... in fact...

    http://visualioner.files.wordp...

    --
    Do what thou wilt shall be the whole of the Law ::: Love is the law, love under will
  18. Re: Whoa, tiny planet!! by kyjellyfish · · Score: 1

    The leading theory says that Mercury survived an early solar system collision, like the glancing blow that a protoplanet had with theEarth, which spawned the Moon. But Mercury's collision was more head-on, which resulted in the majority of it's crust and mantle being blown away. Thus, Mercury's makeup is primarily iron/nickle, like Earth's core.

  19. Sing with me! by funwithBSD · · Score: 1

    It's a small world after all...

    --
    Never answer an anonymous letter. - Yogi Berra
  20. That's funny by DougDot · · Score: 1

    I thought cold caused shrinkage.

  21. Re:Whoa, tiny planet!! by mythosaz · · Score: 1

    Mercury's definately the most Metal planet in the solar system.

    ROCK ON!

    |nn|/

  22. Re:Whoa, tiny planet!! Metal Planet by bbsalem · · Score: 1

    So its average density must be high, and the number of pits and caves on its surface and the collapse features say that volitile elements have been cooked out of what is left. Maybe someone in the know can tell if there is much S on the surface.

    I'm sure that long after we have looked at differentiated planetessimals from the asteroid belt for heavy metals, imagine finding double the reserves of rare Iron group metals, or many times the amount of Au, Pt, Zr, Rh, Pd, Ir, Ti, Zr, out there than on the earth's crust, or better rare earths, that Mercury might be a good place to prospect for refractory heavy metals, ones with high melting points. How Ironic that Hg is probably long cooked off the planet! It would be a tough place to work, though. Most places in the solar system that have metals would have to manufacture refined products out there to make it worthwhile to bring them to earth,