Slashdot Mirror

← Back to Stories (view on slashdot.org)

The Moon Is Shrinking Like a Wrinkled Apple

Posted by Soulskill on from the that's-no-apple dept.

astroengine writes "New observations by NASA's Lunar Reconnaissance Orbiter have uncovered a number of previously unknown, recently formed 'lobate scarps' — raised cliffs about 9 meters high and several kilometers long — over the lunar surface. These scarps form along thrust faults where compression forces the moon's crust to rise. Up until now it was thought these lobate scarps only occurred around the lunar equator, but the high resolution LRO imagery suggests they are ubiquitous, regardless of latitude. As the moon is geologically inactive, what could be creating these features? It would appear the moon's surface is acting like the skin of an apple surrounding the shrinking, dehydrated flesh of the fruit; the lunar crust (skin) is wrinkling as the body of the moon (the flesh) shrinks due to cooling contraction inside the moon's core."

16 of 116 comments (clear)

  1. The analogy is all wrong by Anonymous Coward · · Score: 3, Funny

    This more like the aging of a round of cheese.

    1. Re:The analogy is all wrong by 2.7182 · · Score: 4, Funny

      "That's no moon - it's an aging round of cheese."

      "An aging round of cheese? No one could make an aging round ..... wait a minute...Chewie quick, get out the crackers..."

  2. Amazing by Ardeaem · · Score: 5, Funny

    It's amazing that can happen over the span of just 6,000 years.

  3. It's just by JustOK · · Score: 4, Funny

    it's just shrinkage cuz it's cold in space. Happens to every moon, doesn't it?

    --
    rewriting history since 2109
  4. Al Gore says.. by al3k · · Score: 5, Funny

    It's lunar cooling!!

  5. Wrinkled Apple by Inda · · Score: 5, Funny

    All this Apple bashing on Slashdot is doing my head in. Can't you just give it a rest for a single day?

    I'm so angry. Cancel my subscription. I'm done here.

    --
    This post contains benzene, nitrosamines, formaldehyde and hydrogen cyanide.
  6. Tides? by egburr · · Score: 4, Interesting

    My first thought was couldn't this be more of a tidal effect than due to shrinking? After all, look at what the orbiting mass of the moon does to our oceans. Wouldn't the mass of the earth have a similar effect on the moon? Even if it is tide-locked so the same face always faces the earth, surely there's some slight wobble to that that would cause stress.

    --

    Edward Burr
    Having a smoking section in a restaurant is like having a peeing section in a swimming pool.
    1. Re:Tides? by Peach+Rings · · Score: 5, Funny

      Hur dur, except that's exactly what was surprising about finding the scarping places other than the lunar equator.

    2. Re:Tides? by Froze · · Score: 3, Interesting

      I think the idea is that tidal distortions would be almost exclusively limited to the equatorial regions, this appears to be radially isomorphic, indicating that it is not the result of tidal stress.

      --
      -- The morphemes of your disquisition are ascertainable, but they have eschewed an ambit of transpicuous exposition.
    3. Re:Tides? by ewskau · · Score: 3, Interesting

      The article does not mention this at all, but if the moon is shrinking then its rotational period must be getting shorter (angular momentum). There does not seem to be an indication that the period of the moon is decreasing, suggesting its either too small of an effect, not there, or not being looked for.

    4. Re:Tides? by mea37 · · Score: 3, Interesting

      Interesting point. However, I think tidal locking makes it a little more complicated than that.

      I'm not sure what happens when a tidally locked satelite's diameter gradually changes, but given that tidal locking is an equalibrium state it seems reasonable to suspect that the tidal lock is preserved.

      If so, then as the moon's rotation would naturally tend to speed up, the Earth would pull back on it. This would reduce the increase in rotation, but to preserve angular momentum it would also have to increase the orbital period - meaning the moon would move to a lower orbit with both its period of orbit and its period of rotation slightly reduced.

    5. Re:Tides? by osu-neko · · Score: 5, Interesting

      This would reduce the increase in rotation, but to preserve angular momentum it would also have to increase the orbital period - meaning the moon would move to a lower orbit with both its period of orbit and its period of rotation slightly reduced.

      You were right before the dash: it will increase the orbital period, not reduce it as you said (contradicting yourself) after the dash. This will push the moon into a higher orbit, not a lower one. And indeed, the moon is moving 38mm further away every year, although this is primarily due to the same effect slowing the Earth's rotation rather than the Moon's.

      --
      "Convictions are more dangerous enemies of truth than lies."
  7. Geologically inactive? by Hatta · · Score: 4, Interesting

    That the moon is undergoing these kinds of changes shows that the moon is geologically active. There may be no convection going on in its core, but this is still geological activity.

    --
    Give me Classic Slashdot or give me death!
  8. Well duh. by sootman · · Score: 3, Insightful

    Of course the moon is shrinking like an old apple. Someone left it out sitting in the sun.

    --
    Dear Slashdot: next time you want to mess with the site, add a rich-text editor for comments.
  9. Re:In this manner.... by mortonda · · Score: 3, Funny

    Only it's not quite as old....

  10. It gets old ... by PPH · · Score: 4, Funny

    ... it gets wrinkled.

    Pretty soon, it starts yelling at the kids to stay off its lawn.

    --
    Have gnu, will travel.