Changing Planet

Ice, Ice Mercury

Water ice deposits in craters around Mercury's north pole are seen in this mosaic image taken by the MESSENGER spacecraft, superimposed with a radar image. Courtesy: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory

It’s rare that astronomers declare news with great certainty, given the awesome scope of their work and the level to which they must rely on data gleaned from objects so far away that superlatives quickly run out.

So Thursday’s announcement about the confirmation of water ice (as opposed to, say, carbon-dioxide or methane ice) in Mercury’s poles was, as the scientists put it, an “exclamation point” rather than a plain old period.

Three separate research papers, published in Science Express this week, all arrived at the same conclusion: that the planet closest to the Sun harbors a wealth of water ice, plus dark deposits believed to be organic compounds delivered by comets and asteroids.

The amount of ice is astounding—something on the order of 100 billion to a trillion metric tons.  Or, as David Lawrence of the MESSENGER Mercury mission team says, the rough equivalent of layering Washington, D.C. with 2 to 2.5 miles of ice.


The evidence derives from data gathered by the MESSENGER spacecraft that’s orbiting around Mercury.  Part of its mission has been to confirm theories about the presence of water ice, first ventured 20 years ago when radar measurements from Earth discovered “radar bright” areas in Mercury’s polar regions.

With MESSENGER actually orbiting the tiny planet, scientists could apply three key tests: a neutron spectrometer, which tests for the presence of hydrogen; the reflectance of the polar deposits at near-infrared wavelengths; and thermal models of the surface based on the planet’s actual topography.

“To have them all come together in this way is like getting a key that turns, and the door opens,” says Lawrence, senior scientist at Johns Hopkins University Applied Physics Laboratory.

The confirmation of a long-held theory has an even larger ramification—Mercury as a planet of astrobiological interest, says Sean Solomon, principal investigator of the MESSENGER mission.

“Messenger has revealed a very important chapter in the story of how water ice and other materials have been delivered to the inner planets we think by comets and asteroids,” he says.  “It’s amazing this history is so well-preserved on the planet closest to the sun.

“This isn’t to say we expect to find life on Mercury, but in the book of life there are some early chapters, and Mercury may indeed tell us something about those early chapters.”

  • Ajay

    This disproves your long held belief that the optimum distance from sun is necessary for life to grow spontaneously. So your theory of evolution is just blah di blah di blah… Don’t waste our time with your evolution non-sense.
    Just the other day another scientific report said that the intelligence of mankind is going down with time.
    Thank you

  • Cathy Koentges

    @Ajay. If you aren’t interested in scientific theories, why are you reading scientific articles? It is so disappointing to encounter your comment, when one would wish for some pertinent remarks.

  • Claire

    The article was about ice on the planet Mercury, giving us clues to our own history, how does that in any way disprove anything? It is new information, not a disproval of old information. You sound like one of the test subjects used in that intelligence report…

  • McSlice

    Did anyone else read the article about a water jet that is shotting out of a black hole? It was a while ago, but I believe that it was a black hole. Anyway, perhaps this astroid delivered water is not the correct theory. It seems there could be a chance that the water mentioned would have froze and became affected by the gravity of other planets, while it was aimlessly moving through space, and such yet staying far enough away from stars not to melt while others would surely not avoid planets and leave liquid water on some planets closer to their parent star, like Earth, just a thought. Then they eventually slam into planets far enough away to stay frozen. Thus depositing the different amounts of water that have been found like on Mercury and other planets. This is just a thought that ran through my head so it has not been really thought out. I am sure that I will get some negative feedback. So before someone tells me I am dumb, ha ha, remember it’s just an idea I am not saying it is what happens.

  • Jas

    Ajay, well if you knew anything about science son, you would realise science itself is a matter of constantly evaluating, re-evaluating, rediscovering, self evaluation etc etc. Clearly something which people that hold the ‘creationist’ or similar views simply do not do. and that, is why science moves forward, and the others do not.

  • Baugmo Boraxis

    1) Don’t feed the trolls. This could be a worthwhile discussion.

    2) Why not life on Mercury? The surprising thing is solid water in an unexpectedly warm place, right? So surely some of it must be liquid. Why else would God put so much water so close to the sun?

  • andmikel

    The implication of this is that a manned mission to land on Mercury may be feasible in the future.

  • Chris

    It is fascinating to think that ice can form and stay that way in the extreme temperature of Mercury. From 400 degrees C in the day to – 200 degrees C at night, it makes you wonder how the water does not simply boil off and escape into space. This is why i love science!

  • Shaihaan

    George, please don’t forget that the temperature -275 C is not possible under the Kinetic theory. The lowest possible temperature is -273 C. The lowest temperature achieved by humans is -269 C.

  • Steve

    @Shaihaan: Unlike most of the rest of the planet, the United States uses Fahrenheit, not Celsius; I’m sure George, being from Wyoming, meant -275 F, which is about -170 C.

  • Anu

    The mysteries of the known universe, those that are seen and those that are not, cohabitate the same place and the same time although time can differ even within the same place.

    Exploration leads one to knowledge and greatness.

  • V-man

    This is exciting to anyone who likes astronomy like I do, I just expected this to be more of a discovery for Mars.

  • Thomas

    Is it possible that there could be single-cell organisms under all that ice?

  • Golden Retriever

    FAKE !!

  • A. Desiato

    If one doesn’t know the size of Washington DC how can one know the size of the amount of ice. I hate it when writers of articles do this.
    It’s always fascinating when there are new discoveries about space.

  • A. Desiato

    why are you on a science site? You have the right to believe or not to believe but you know what we don’t care.

  • Omar Zobair

    Let them say something, at least we would know from their speeches some word,, even fascinating.
    Thanks All

  • Cheng Tuyi

    that is amazing, that is my dream to walk on this planet

  • Cheng Tuyi

    that is amazing. that is my dream to walk and play on this planet

  • Annabella

    I love science and espicaly ASTRONOMY.
    Thats great news. Scientists please discover more and more about our planet (Earth) and discover more and more about space.
    National Geographic is the best scientific channel.

  • Annabella

    Well some people doesn’t believe this but why not?
    It is true. Many things are happening in this universe that we are not aware from.SO more researches must have been done and especially about our UNIVERSE and SOLAR SYSTEM and SPACE. And we really have to stop polluting because we are breaking our OZONE LAYER or The Earth’s Layers.

  • chowy

    thats not true at all

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