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Space Science

How Water Forms in Interstellar Space at 10K 270

KentuckyFC writes "Water is the most abundant solid material in space. But although astronomers see it on planets, moons, in comets and in interstellar clouds, nobody has been able to show how it forms. In theory, it should form easily when oxygen and atomic hydrogen meet. The problem is that there is not enough of it floating around as gas in interstellar dust clouds. So instead, the thinking is that water must form when atomic hydrogen interacts with frozen solid oxygen on the surface of dust grains in these clouds. Now Japanese astronomers have demonstrated this process for the first time in the lab in conditions that simulate interstellar space. That's cool because all the water in the solar system, including almost every drop you drink on Earth today, must have formed in exactly this way more than 5 billion years ago in a pre-solar dustcloud (abstract)."
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How Water Forms in Interstellar Space at 10K

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  • Where do all the Oxygen atoms come from ... I'm guessing fusion from within stars?
  • Must it? (Score:5, Insightful)

    by pla ( 258480 ) on Monday May 05, 2008 @10:25AM (#23300338) Journal
    That's cool because all the water in the solar system, including almost every drop you drink on Earth today, must have formed in exactly this way more than 5 billion years ago in a pre-solar dustcloud

    Why must it? Could you justify that statement?

    Gravity alone tends to cause interstellar clouds to collapse into stellar accretion disks, and then into stars and planets.

    Although the Hydrogen and Oxygen in the original cloud may have had almost zero chance of getting together, once the cloud collapsed into relatively dense planetary atmospheres, why couldn't water have formed then?
    • by Ferzerp ( 83619 )
      That and water is relatively easy to break apart, put back together, recombine with other things, etc.

      It wouldn't be far fetched to think that only minute amounts of the current water on earth was formed this way.
    • Sure looks that way (Score:5, Informative)

      by tjstork ( 137384 ) <todd.bandrowsky@ ... UGARom minus cat> on Monday May 05, 2008 @10:35AM (#23300482) Homepage Journal
      Why must it? Could you justify that statement?

      The problem is that the Earth doesn't have sufficient gravity to hold free hydrogen. Free hydrogen on earth goes by by into space. So that almost automatically rules out any free hydrogen / oxygen hypothesis... or at least renders it less likely.

      Now, so, maybe there is some sort of hydrogen compound and some sort of oxygen compound that could react on earth to form water. Well, then, you'd have to ask, where's the traces of those reactions occuring, and, are there any minerals out there today that support those conclusions. Right now, you can find oxygen in just about any good old mineral, but hydrogen, I think that's an entirely different mater. I'm not a geologist, but I'm pretty sure that the only hydrogens we find on earth are from organic compounds, and they get it from a reaction that ultimately originates with water as one of the reagents.

      Now, that is of course based on a geological understanding that goes maybe at most a mile or two into the earth's crust. There could be some sort of something in the mantle where, ahah, there is a ton of hydrogen... you know, like water is formed from some hydrogen bearing rock mixing with some oxygen bearing rock inside the earth and shoots up out of a volcano. IF you could somehow find a set of candidate rocks and then make a good case for it, inside the earth, consistent with what we already know from the geological record about how the earth was formed, then yeah, you'd probably refute the underlying assumption of these japanese scientists and be some kind of a hero.

      But you'd be a bigger hero than that... because, if you actually could find a non-organic source of hydrogen on the earth you'd be a huge hero, because you would have discovered a fairly green non-fossil fuel. Good luck with that!
      • I guess the point still remains "Why must it? Could you justify that statement" .

        Even with your understanding of hydrogen, the possibility of it coming from a rock or a reaction with a rock could simply mean that asteroids or meteors impacting the earth in the past could release enough Hydrogen to produce the amount of water on earth. The hydrogen release could be extinguished by now or buried at the bottom of an ocean somewhere where the pressure of the water above it retards the production or release of h
      • The problem is that the Earth doesn't have sufficient gravity to hold free hydrogen
        But the accretion disk around the primordial sun had sufficient gravity and density, didn't it?
      • by brunes69 ( 86786 )
        Without looking into all your points, I am pretty damn sure that things don't happen as you describe.

        You have three points here that don't go together:

        - The only hydrogen compounds on earth are in organics and water
        - Organics got their hydrogen compounds soely through reactions with water
        - Free hydrogen escapes into space

        If all of these were true, the total amount of water on earth would be constantly decreasing, and would have been for billions of years. This is not the case - the amount of water on earth
        • by Hatta ( 162192 )
          As far as I remember from my university chemistry and biology classes, organics don't, for the most part, break down water ever.

          Water is broken down all the time in hydrolysis [wikipedia.org] reactions.
        • by tjstork ( 137384 )
          If all of these were true, the total amount of water on earth would be constantly decreasing, and would have been for billions of years. This is not the case - the amount of water on earth is relatively constant. As far as I remember from my university chemistry and biology classes, organics don't, for the most part, break down water ever.

          Some biology class! :-)

          Photosynthesis:

          6H2O + 6CO2 ----------> C6H12O6+ 6O2

          http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html [maricopa.edu]

          If all of these were true, the
          • by brunes69 ( 86786 )
            Oh I forgot about plants :P

            But photosynthesis doesn't really count because that process doesn't so that the OP described, break the hydrogen off to use the oxygen. It does the opposite, it breaks the oxygen to create the organic compound, which is fine, because that keeps the hydrogen in the organic cycle.

            What biological process breaks water apart to release hydrogen?
        • As far as I remember from my university chemistry and biology classes, organics don't, for the most part, break down water ever.
          Well, photosynthesis [wikipedia.org] is one of the most important processes in life on our planet. It breaks down water.
      • The problem is that the Earth doesn't have sufficient gravity to hold free hydrogen
        What are you talking about?

        Sure, hydrogen released at sea level will rise to the outer surface of the atmosphere. But that's only because it's the least dense gas in existence, and all the other heavier gases push it up due their own higher gravity. Eventually, the hydrogen would reach a point where the pull of gravity and the "push" of the rest of the atmosphere would even out.

        Some hydrogen will get away due to thermal escape (an individual molecule moving fast enough to have escape velocity), but the earth will also collect some hydrogen due to the solar wind and its ordinary passage through space.

        I wager that the 1ppm we have of atmospheric hydrogen is a few orders of magnitude greater than the atomic hydrogen present in the vacuum of space -- even if we disregard the amount of hydrogen that has bonded with oxygen in our little dust-ball.

    • Although the Hydrogen and Oxygen in the original cloud may have had almost zero chance of getting together, once the cloud collapsed into relatively dense planetary atmospheres, why couldn't water have formed then?

      The problem with that is where we find water. We see a lot of water in the form of comets that couldn't have come from something as big as a planetary body. So the conclusion is water must have formed before planetary bodies. I believe the thinking is most of the water on earth came from comets
      • by mikael ( 484 )
        I was wondering whether it would be possible for water to form from the turbulence within the outer layers of a star - the mixing of oxygen formed from fusion and the unyet fusioned hydrogen.
    • but the interstellar dustcloud waterchild concept wins hollywood glamor points, while your more reasonable point of view is mundane and humdrum

      it is a facet of scientific theory formation known as michael bayification: the more dramatic and trippy the theory, the more likely it is to spread in the popular press, and therefore to gain more traction in the minds of the average joe

      "5 billion interstellar dustcloud water" is just so cool sounding man. while your point of view is full of zzz

      so c'mon, get with the program, your ideas are just so drab. perhaps if you redescribed your theory as it would appear being mumbled by a secret military organization figurehead in a big budget disaster movie. make believe you are a 23 year old hollywood script writer perusing wikipedia in forming your scientific mumbo jumbo

      repeat after me: "hyperplanetary accretion disc catalysis"

      or "gravity well coupled reverse electrolysis"

      there you go, now we are playing in the big leagues of science-theory-by-public-relations-ad-copy-writer
    • by Hatta ( 162192 )
      Not to mention that just about every water molecule must has probably been broken apart and reformed several times by organic activity.
    • I'd always assumed that it was formed from ions:
      - Oxygen atom collects a lose electron or two to form a negatively-charged oxygen ion.
      - Oxygen ion collects a lose proton or hydrogen atom to form a hydroxyl ion (or "atom")
      - Hydroxyl ion collects a lose proton, or
      - Hydroxyl "atom" collects first an electron then a proton.

      No surface necessary: The captures can start out very tenuous (say, due to interactions with additional particles or magnetic fields in a gas cloud) and then
  • Comment removed (Score:4, Insightful)

    by account_deleted ( 4530225 ) on Monday May 05, 2008 @10:27AM (#23300376)
    Comment removed based on user account deletion
    • Re: (Score:2, Interesting)

      by maxume ( 22995 )
      There is somewhere between 100,000 and 2,000,000 times as much water on earth as there is biomass(go ahead and find a better estimate on how much water there is, biomass is close enough to 2,000 billion tons, which is 6.7*10^14 kg).

      Given a million years, not very much of that needs to be cycled each year for most of it to have been organic matter at some point, but it would be interesting to see just how much of the water in a plant is newly created(and the percentages of water that a plant destroys and cre
      • One way to estimate this is to look at the carbon respiration of the planet. It takes 4 or 5 years for the amount of carbon we put into the atmosphere to equal the amplitude of the seasonal variation and the seasonal variation is a rough indicator of the amount of cycling that biomass does. If we assume equal molar quantities of water and carbon dioxide get cycled and note that we put about 7Gt of carbon into the air each year then at least 20Gt of water gets turned into hydrocarbons and turned back into
    • by MrMr ( 219533 )
      I always used to think that, except when I looked up the residence time of my local water supply ( http://en.wikipedia.org/wiki/Water_cycle [wikipedia.org] - deep ground water) I discovered that there is an 80% chance that I have not been drinking dino-piss after all...
    • Re:To be correct.. (Score:4, Interesting)

      by tygt ( 792974 ) on Monday May 05, 2008 @11:02AM (#23300836)
      At first I was tempted to state "water is used organically but remains water"; however this is not always correct.

      Dredging my memory from a high school class about 30 years ago, photosynthesis utilizes water and recombines the molecules:

      CO2 + H2O + sunshine => C6H12O6 + O2

      Apologizes for the lack of subscripting; I tried and failed...

  • That's cool because all the water in the solar system, including almost every drop you drink on Earth today, must have formed in exactly this way more than 5 billion years ago in a pre-solar dustcloud

    in the immortal words of Keanu Reeves: "Whoaaa"

    also forming in that dustcloud 5 billion years ago were minute traces of lysergic acid diethylamide. slight traces of which may also enable you to appreciate the far-out implications of you being a 5 billion year old dustcloud waterchild

    duuude

  • by cmacb ( 547347 ) on Monday May 05, 2008 @10:28AM (#23300386) Homepage Journal
    I knew my tap water tasted funny.
  • by suso ( 153703 ) * on Monday May 05, 2008 @10:32AM (#23300448) Journal
    You don't have to try it figure it out. God just creates it. No scientific explaination needed. Now wasn't that easy.
    • Re:How water forms (Score:4, Interesting)

      by dkleinsc ( 563838 ) on Monday May 05, 2008 @11:45AM (#23301356) Homepage
      Actually, if you read the very beginning of Genesis closely, you'll notice that God doesn't create water:
      "And the Spirit of God was moving over the face of the waters."

      That's before light exists.
  • All water? (Score:3, Funny)

    by teslar ( 706653 ) on Monday May 05, 2008 @10:32AM (#23300452)

    That's cool because all the water in the solar system, including almost every drop you drink on Earth today
    So, what are the drops of water that are not included in the "almost every drop" made of? :)
    • Re: (Score:2, Interesting)

      by Zcar ( 756484 )

      And is it really "almost all"? Water is a product of many common metabolic chemical reactions (e.g. the catabolism of glucose produces 6 water molecules per glucose molecule catabolized). Similarly, water is destroyed in photosynthesis to produce glucose.

      I'd imagine a sizable proportion of the world water supply has taken part in these processes at some point or other.

  • Water is the most important thing needed for life. The hard part of life isn't explaining how water forms, but how inantimate, dead chemicals can become alive. As far as we know so far, life has never arisen anywhere but here, although despite any lack of proof it's assumed that we are not alone.
  • "Water is the most abundant solid material in space. " Hmm, solid water. If only we had some term to describe this stuff.
  • That's cool because all the water in the solar system...

    Uh, yeah, like cause 10K is -441.4 degrees Fahrenheit or -263 degrees Celsius.

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