Water and Mercury do mix!

By Phil Plait | July 3, 2008 10:57 pm

In a press conference held on July 3, scientists announced that the MESSENGER probe has detected water in the very tenuous atmosphere surrounding Mercury.

It’s OK if you want to read that again. I had to comically rub my eyes with my fists myself.

I needn’t go into details, since Emily has a thorough article about it. While this is truly weird, it’s not entirely unexplainable. But still. Wow.

CATEGORIZED UNDER: Astronomy, Cool stuff, NASA, Science

Comments (21)

  1. Mercury has an atmosphere? And vulcanism? Amazing. 2008 is turning out to be a very good year for “finding stuff out”. The cool thing is the more they discover the more questions that are raised. I learnt more about Mercury in that one article from Emily than I can recall ever learning before. Yay science.

  2. madge

    WoW indeed. Good Job Messenger! Great article Emily!

  3. John Phillips, FCD

    I second shane and madge as well as another well deserved yay science.

  4. I wonder how much water that amounts to, and if any of it ever gets trapped in Earth’s atmosphere.

  5. Amazing! Though I have to say reading about water on otherwise parched planets never fails to make me thirsty.

  6. Nathan Myers

    Why not doubly-ionized chlorine and silicon? It looks like there’s lots of 32, 35 and 36 there.

  7. IBY

    Yay! (somehow, I am not feeling the excitement, though)

  8. Since it’s looking like water is apparently quite common, can the discovery of life be far behind?

  9. jest

    Not too surprising. Comets go hurtling towards the sun on a fairly regular basis. Mercury scoots around the sun and would likely intercept some of these doomed bodies of ice. The result? Water in Mercury’s atmosphere. Of course, I had never thought of this until Messenger actually reported it. It just makes sense though, even if it’s surprising that any water manages to survive in Mercury’s atmosphere. THAT’S the cool part.

  10. Rav Wisnton

    I think my brain asploded. But in a good way.

    This is awesome!

  11. Jason

    @Nathan: Yeah, that’s what I’m thinking too. S2+ or S2- would show up as a peak at 16, and Wikipedia (if you’re willing to assume it’s getting this right) says that those two ionizations are common.

    Unless there’s some non-obvious reason I’m missing here, that peak in the “water group” is encouraging, and worth a second look, but not necessarily indicative of good ol’ H2O

    (Apologies if the comment editor doesn’t allow markup. I don’t see a list of approved HTML, or a preview button.)

  12. Simon C.

    @Jason + Nathan : I am convinced they considered it very seriously, but I suspect it doesn’t add up if you try to see what parts of that peak is caused by trace amounts.

    Now, if only someone had the time to calculate the rate at which water molecules escape Mercury’s atmosphere…

  13. Huh. I didn’t figure that Mercury even had an atmosphere. Wow!

  14. Alex

    Hot damn! That’s pretty strange indeed, and very interesting.

  15. jest

    There goes Mercury, trying to steal Mars’ thunder.

    Don’t shoot the MESSENGER. lol.

    (I honestly couldn’t help it)

  16. quasidog

    The obvious thought would be the Sun having blown the water and atmosphere all away by now. It must be being held or protected there by something else like a magnetic field or something. Does Mercury have a magnetic field ? Wouldn’t it’s extremely low mass fail to hold any form of atmosphere together ? Really strange.

  17. jest

    Well, since the discovery of asteroids with moons, I think there has had to be a lot of rethinking as far as what we actually know about the Solar system is concerned. The science is there to learn though, and 2008 will indeed be quite a great year of discovery.

  18. Nathan Myers

    I suspect there’s lots of pressure at NASA to report anything that could be water as water. The PR staff hate publishing reports that say “it could be water or chlorine, who the hell knows?”.

  19. Jarrad

    oh goodness. just wait until hoagland gets wind of this…

  20. Torbjörn Larsson, OM

    Not so surprising as solar wind hydrogen sputtering of oxide minerals have been proposed to nicely account for the amount of putative Moon water. Nothing is new under the Sun! [BA pun.]

    And of course we have scifi speculating way before this. Stephen Baxter describes the Mercury atmosphere replenishment and water cycle in the chapter “Cilia-of-Gold” in Vacuum Diagrams, here driven by the solar wind (hydrogen/helium atmosphere) and heating (water from rocks), to snow down in a deep polar crater. (And provide a habitat for the descendants of a crashed space ship., such as Cilia-of-Gold.)

    Btw, browsing I see that Baxter puts Mercury shrinkage down to closer to two kilometers (in 1997) instead of four, so if there is a future ed he has some revising to do there as well. A recurrent problem of sufficiently “hard” scifi. ūüėõ

    I suspect there’s lots of pressure at NASA to report anything that could be water as water.

    Perhaps, but that wasn’t the case here. It can be iffy to sort out MA readings, but there is often enough info in them to do it with a reasonable likelihood for the result. It isn’t different from other pattern matching for spectra, genomes, et cetera, YMMV.

  21. quasidog

    OK well to answer my own question .. yes it does have a magnetic field. I Did not know it was so iron rich. One of the later issues of Sky and Telescope Australia had a 4 page article on Mercury’s makeup. Talk about timing ;p


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