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Shadowed Lunar Craters May Be Coldest Spot In the Solar System

Posted by Soulskill on from the alright-niven-get-cracking dept.

sciencehabit writes "Science reports: 'What's the coldest spot in the solar system? For now, that distinction belongs to permanently shadowed craters near the moon's south pole, according to the first results from the Lunar Reconnaissance Orbiter (LRO) spacecraft announced today at a NASA press conference. Another instrument has returned hints of water ice in some of these cold spots, ... but it also showed signs of water ice in impossibly hot places, too.'"

10 of 108 comments (clear)

  1. Sterling Engine! by Anonymous Coward · · Score: 1, Informative

    I RTFA and Pluto is 44 Kelvin. This is the average temperature, no doubt there is some crevasse on Pluto, but it hasn't been measured.

  2. Really? by Useful+Wheat · · Score: 3, Informative

    Since nobody is going to read it, the coldest temperature is 33K. The reason they care is because they'll probably find a lot of ice there.

    I'm not sure how I feel about this. I was of the understanding that space was on the order of 3K due to the cosmic background radiation. 33K is positively warm compared to this.

    1. Re:Really? by G33kGuy · · Score: 2, Informative

      Space isn't really cold as there isn't anything to be cold. As for tiny particles in space, their temperature would vary greatly depending on their distance from the sun (or other heat source).

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    2. Re:Really? by rm999 · · Score: 2, Informative

      See http://www.wisegeek.com/what-is-the-temperature-in-space.htm

      It says that space is ridiculously empty *on average*, so a molecule floating around in the middle of nowhere probably has virtually no energy (except the cosmic background radiation). This is why the average temperature of space is so low.

      On the other hand, a molecule in our solar system gets hit by all sorts of radiation if it had direct line of sight with the sun, heating it to >40 kelvin.

    3. Re:Really? by IWannaBeAnAC · · Score: 2, Informative

      The 3K temperature comes from the background radiation in `empty' space (mostly photons, but longer wavelengths than visible light). If you are close to a star like the sun, you clearly get a lot more radiating heat than that. Satelites, for example, have heat shields to protect them from getting too hot and melting. Similarly, the surface of the moon that is in direct sunlight gets quite warm, about 75 degrees Fahrenheit (about 125 degrees C, so above the boiling point of water, if it was at standard pressure).

  3. You mean "Coldest Naturally Occurring Spot" by Scorpinox · · Score: 4, Informative

    The coldest spot in the universe would be in Boulder Colorado where they do absolute zero experiments.

    [source: http://www.smithsonianmag.com/science-nature/phenom-200801.html ]

    1. Re:You mean "Coldest Naturally Occurring Spot" by Criliric · · Score: 4, Informative
      no where on that page does it say that they have made it to absolute zero... infact:

      Physicists acknowledge they can never reach the coldest conceivable temperature, known as absolute zero and long ago calculated to be minus 459.67F.

    2. Re:You mean "Coldest Naturally Occurring Spot" by Anonymous Coward · · Score: 2, Informative

      That doesn't mean they can't do experiments related to absolute zero including attempts at approaching it.

      He didn't say they did experiments "at" absolute zero.

  4. Re:Excuse my ignorance...just asking... by perrin · · Score: 2, Informative

    No, you need gravity to hold an atmosphere, much more than the Moon currently has. A strong magnetic field helps, but is not necessary, as in the case of Venus.

  5. Re:Suprise to me... by AJWM · · Score: 2, Informative

    They have volcanoes of liquid nitrogen on those moons for pete's sake.

    But nitrogen freezes at 63 K, so that liquid nitrogen is at least twice as warm as the 33 K found on the Moon. Now, if those moons have craters at their poles that are permanently shielded from sunlight....

    (Actually there are other factors in play, like the thermal conductivity of whatever the moon in question is made of, heating effects of tidal friction, etc.)

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    -- Alastair