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Planet Mercury Has Shrunk More Than Thought 58

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."
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Planet Mercury Has Shrunk More Than Thought

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  • by toonces33 (841696) on Sunday March 16, 2014 @07:01PM (#46501723)

    Easy mistake to make.

  • by Anonymous Coward on Sunday March 16, 2014 @07:05PM (#46501747)
    It's the girth, not the length that matters.
  • Shrinkage (Score:3, Funny)

    by Tippler (3027557) on Sunday March 16, 2014 @07:09PM (#46501771)

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

    • by banda (206438) a frightened turtle

    • 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.

  • by koan (80826)

    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.

    • Re:Laugh (Score:5, Informative)

      by Shakrai (717556) * on Sunday March 16, 2014 @07:17PM (#46501799) Journal

      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. :)

      • by Anonymous Coward

        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 i

        • by asylumx (881307)
          I think you're talking out of Uranus.
        • Re: (Score:2, Informative)

          by Anonymous Coward
          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.
  • by Anonymous Coward

    ...but Uranus is expanding!

  • by Culture20 (968837) on Sunday March 16, 2014 @07:43PM (#46501917)
    Space is cold!
  • In other news, your mother's diameter has expanded by 2km.
  • 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.

  • It's a small world after all...

  • I thought cold caused shrinkage.