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Space Science

Asteroid Crashes Likely Gave Earth Its Water 138

Posted by samzenpus
from the space-water dept.
Diggester writes "Asteroids from the inner solar system are the most likely source of the majority of Earth's water, a new study suggests. The results contradict prevailing theories, which hold that most of our planet's water originated in the outer solar system and was delivered by comets or asteroids that coalesced beyond Jupiter's orbit, then migrated inward."
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Asteroid Crashes Likely Gave Earth Its Water

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  • by gameboyhippo (827141) on Sunday July 15, 2012 @01:27PM (#40656663) Journal

    So rocks carrying massive amounts of water magically came to the Earth?

    • Now we need to find a way to crash land a comet into mars.

      So we can get our ass to mars.

      • by dryeo (100693) on Sunday July 15, 2012 @04:11PM (#40657723)

        Better yet, crash Ceres into Venus. A 9.43 ± 0.07×1020 kg mass crashing at 10 miles per second would probably blow most of the atmosphere off and Ceres is largely water.

        • by Anonymous Coward

          Better yet, crash Ceres into Venus. A 9.43 ± 0.07×1020 kg mass crashing at 10 miles per second would probably blow most of the atmosphere off and Ceres is largely water.

          You nerds scare me.

        • by drsquare (530038)

          I'm pretty sure that Ceres is heavier than ten tonnes.

        • by RockDoctor (15477)

          crash Ceres into Venus.

          OK, with you so far.

          A 9.43 ± 0.07Ã--1020 kg mass crashing at 10 miles per second would probably blow most of the atmosphere off

          does Slashcode not know how to handle either this 10^20 exponent operator, or this one 10**20? Or is your keyboard set up to post some non-Latin characters?

          Whatever about bloody Slashcode!

          do you care to quantify "most of the atmosphere"? My back of the thumbnail estimate is that the 487km diameter Ceres would carve an initial crater some

    • by Grog6 (85859) on Sunday July 15, 2012 @01:34PM (#40656715)

      The four Elephants contributed a lot less.

      Humanity's very existence is proof against Intelligent Design.

    • by Tukz (664339) on Sunday July 15, 2012 @01:39PM (#40656743) Journal

      Frozen rocks basically, but yes.
      They slammed into earth.

      Watch some Discovery or read some books some times.
      This is nothing new.

      What may be new, is the fact that these asteroids may be from further away than first anticipated.

      • by Anonymous Coward
        The title says 'crash' which implies a plan and an accident, therefore intelligent design. I think collision would be a more appropriate term.
      • Or play SimEarth
      • by Daetrin (576516)
        Entirely correct, except that what may be new now is that those asteroids may _not_ be from further away than first anticipated.
      • Actually, not frozen rocks in this case. That was the old theory.

        Here, the deuterium ratios match that found in chondrites from the inner solar system (they estimate the asteroid belt area), and that these then broke down, giving up oxygen and hydrogen, which then formed water.

    • Re: (Score:2, Insightful)

      by schitso (2541028)
      Saw that this was modded up.
      Expected it to be +1 Funny
      Is +1 Insightful
      :(
    • Just like trolls were destined to collide with /. and flood her boards.
    • by Anonymous Coward

      How many asteroids does it take to give us the water we have?

      • by symbolset (646467) *
        A lot of little ones, or a few big ones. One remaining asteroid that we know of - 1 Ceres - has as much water on it as all the fresh water on Earth. There's quite a lot more water on Earth than we can see though - it's just mixed in with the rock, trapped in the mantle.
    • Close, but not quite. What the article is saying is that rocks carrying massive amounts of water naturally came to the Earth.

      PS All non-zero amounts of water are massive.

    • by Black Parrot (19622) on Sunday July 15, 2012 @02:29PM (#40657023)

      So rocks carrying massive amounts of water magically came to the Earth?

      Yes, and the Intelligent Designer's son turned some of it into wine.

      • Which, if true, makes his death a crime against humanity. A source of wine cheaper than water...;-)

      • by Maritz (1829006)
        Careful, you'll annoy the cDesign Proponentists, they don't appreciate being linked with a recognisable deity (that they all fervently believe in) lest they appear to be less impartial/reasonable than they'd like to appear.
    • by amck (34780) on Sunday July 15, 2012 @02:30PM (#40657037) Homepage

      Some people call it gravity.

      Note: Earth has about 0.1 - 0.01 % water by mass (depending on how much water you think there is in the mantle). Compared to the outer solar system (typically 50%) it's not _that_ massive.

    • by tragedy (27079) on Sunday July 15, 2012 @02:50PM (#40657145)

      If you consider gravity to be "magic", then yes.

      • Until we can explain how it works, you can't prove it isn't magic.
        • by tragedy (27079)

          Ultimately, I don't know if I consider anything to be magic. If you could give me absolute proof of fairies in the bottom of the garden who make the flowers grow, I would be amazed, but I would also consider them to be part of the natural world. I would be extremely interested in how they could be reconciled with our existing knowledge, theories and observations.

          In any case, how gravity works at a fundamental level is pretty much irrelevant to the discussion. We know that gravity works and that we can know

    • by PNutts (199112)

      Please be patient while we work on what you belive is a work of fiction conflicts with your work of fiction.

    • I think the intelligent design stroke is in making such asteroids STOP hitting the earth.

      Jokes aside: an eternal creator can create a world populated with creatures with free will, completely random interactions, no interference from the creator itself, that ends up EXACTLY how the creator wished. Because the creator creates time too, he is not bound by it. I am not saying this world has random interactions, a creator, free will. I am saying that even by our restricted logic, the creator and the nature of c

    • One day the Earth was so thirsty it asked Space for a drink. Space provided with a steady stream of nicely iced drinks. Eventually the Earth became so drunk that all kinds of creatures appeared.

    • by hemo_jr (1122113)

      Nothing magic about this. These asteroids probably hit during the late, heavy bombardment. According to the Nice model, this is a result of Jupiter and Saturn being in an orbital resonance (Jupiter orbiting once for every two times Saturn orbited). A number of scientists (notable among them, WF Bottke), speculate that the Hungaria family of asteroids was nearly completely depopulated that this time as most were knocked into the inner solar system.

      A recent discovery of an 100 km diameter, 2 bya asteroid cr

  • by Anonymous Coward

    That's the simplest explanation. You nerds and your crazy ideas !!

    • by Brad1138 (590148)
      Wow, you'r right. Why do we spend all this time, effort and money investigating things when the answer is so obvious...
    • That's the simplest explanation. You nerds and your crazy ideas !!

      Best possible explanation for unplanned pregnancies.

  • by cpu6502 (1960974) on Sunday July 15, 2012 @01:36PM (#40656727)

    Hmmm.

    Also it must have been hit by a whole heck of a lot of spacerocks, since 2/3rds of the surface is water. That's a lot of impacts.

    • I think the idea is that the water was always there. That is to say ever since the supernova that seeded us happened. In the case of the asteroids, just like their rocky material, the water would have been part of the mix that coalesced into asteroids. Asteroids are failed planets that didn't attain enough mass to become a planet. They are also relatively small so not much heat would have resulted from their forming. They never got hot enough to boil it off. It's such a strange thing to think of water
    • by MightyYar (622222) on Sunday July 15, 2012 @02:01PM (#40656889)

      It looks like a lot of water, but it's mostly on the surface so it is misleading. Here's a neat graphic. [abovetopsecret.com]

      • by dissy (172727)

        Wow, that is am impressive graphic. Thank you.

        I was aware that the atmosphere was extremely thin relative to the earths diameter.
        But I had no idea the total water volume would be even less than that!

      • That is cool. I wonder how big a sphere all the humans would make. And then all the biomass.

    • The Earth was hit by a whole heck of a lot of spacerocks. That's settled knowledge.

      What isn't settled is if the internal rocks were carrying enough water, or if nearly all of it came from the outer parts of the Solar System.

      • by symbolset (646467) *
        Or some of it wasn't trapped by infall and then released by the Late Heavy Bombardment as large chunks of mantle were blasted into mist - which would have been my guess.
  • by poly_pusher (1004145) on Sunday July 15, 2012 @01:41PM (#40656755)
    If this is true then how much water does the moon have? It seems like that should be estimable and relevant to the future if space travel if we assume all the earths water came during the late heavy bombardment. It also could be a good way to test this theory. If concentrations of water on the moon don't correlate wouldn't that poke some holes in the theory?
    • by Anonymous Coward

      No. The earth and the moon formed in drastically distinct environments. The earth was congealing out of the accretion disk and only later was the moon knocked off from our not-quite-solid self. The moon does have more lighter metals than we do.

      • But the moon is still one of the strongest pieces of evidence for the late heavy bombardment. They did form in very different environments but wouldn't they have a similar concentration of water if the water on earth arrived at the same time as our moon got heavily cratered? Earth certainly didn't get this water prior to the moon getting knocked of the earth. It was a swirling ball of magma that would not have held on to any water for quite a while after that event.
        • Re:The moon (Score:4, Interesting)

          by tragedy (27079) on Sunday July 15, 2012 @03:00PM (#40657207)

          The moon has lower gravity than earth and little or no atmosphere for all of its history. Any water on the surface of the moon would be expected to be stripped away by by the solar wind over millions of years, leaving only deposits in shielded locations. Some water would also be created on the moon from the solar wind as well. I think we should reasonably expect with those conditions and that amount of time that the concentrations of water on Earth and on the moon would be nothing alike.

    • by wjcofkc (964165)
      By most modern estimates the moon contains more water than exists on the face of the earth. I will leave it to you to search slashdot for the relevant articles.
    • Maybe, but I would imagine the moon would experience a much greater amount of water loss into space. If one could estimate the differing rates, then maybe the moon could provide another line of evidence.

    • by Brain-Fu (1274756)

      Liquid water does not last long on the moon; the solar radiation boils it away. There could still be water on the moon, though, but our missions there have still barely scratched the surface (so to speak).

      If you are really curious, you could just type the word "moon" into wikipedia. There is a lot of info there.

  • I mean, look at what we see with other protostars forming out there; the compaction of gasses from nebulae... and with the building blocks of water being so extremely common out there (contrary to the plot of 'ice pirates') its only natural that water will condense into these protosystems as well... and water has a tendency to build up a static charge, which would probably influence its distribution, especially in 'warmer' parts of the forming system. I would resume that it would congregate easier closer i
  • If I was the creator of the universe, and had billions of trillions of planets capable of supporting life, what would be the most efficient 'delivery system' for me to use to deliver the "Seeds of Life" to them all? Frozen water. Lots of iceballs with the 'seeds of life' in them. Since all life on earth is based on water, and water is not native to earth, all of our water came from 'out there'. So, if life sprouted on this planet, it stands to reason it's happened everywhere. Ergo, we most likely are n
    • by Black Parrot (19622) on Sunday July 15, 2012 @02:33PM (#40657053)

      If I was the creator of the universe, and had billions of trillions of planets capable of supporting life, what would be the most efficient 'delivery system' for me to use to deliver the "Seeds of Life" to them all?

      If you can create universes, you don't need "delivery systems". You just speak your will into being.

      • If you can create universes, you can pretty much deliver life any damn way you want to, I imagine. Who's gonna tell you no?
        • I've recently heard about the theory of an 'intelligent universe', If it proves out one day to be true, think of the universe as one huge-ass computer that is "alive" & thinking. On a magnitude wa-a-a-y beyond human capacity. It's an interesting theory I heard on the Science channel's "Wormhole" program, the onwe narrated by Morgan Freeman. Heckuva good show.
    • by sheetsda (230887)

      So, if life sprouted on this planet, it stands to reason it's happened everywhere. Ergo, we most likely are not 'alone'.

      Continuing that line of thinking, you may find these two articles interesting:

      http://en.wikipedia.org/wiki/Fermi_paradox [wikipedia.org]
      http://en.wikipedia.org/wiki/The_Great_Filter [wikipedia.org]

      My apologies if you're already familiar with these concepts.

      • Those are both interesting reads, thanks. No need to apologize This is why I dig Slashdot, I'm always learning something new here.
    • by Baloroth (2370816)

      Not necessarily. Water is only one tiny part of the requirements for life (as we know it). Of course it is possible, theoretically, for life to exist in other situations, but that is all we have: theory.

      Before anyone points out that life on Earth has adapted for situations well outside the normal range of Earth life (high radiation or temperatures, for example), the key word there is "adapted". In other words, such life is able to exist because the Earth overall is a fairly easy environment for life to dev

  • Why is it that water had to come from elsewhere, exactly?

    I mean, if it could form on comets or asteroids, why could it not have formed right here on Earth the same way it forms elsewhere? Why is there such a predisposition to the notion that water must have come from somewhere else?

    • When 1st forming, or 'accreating', the earth was way too hot, any water would be boiled away. Once it cooled enough, any bombardment of ice would collect over time into oceans. Yeah, we are talking a lot of ice hitting earth. If anyone has a better explanation, I'm open to it.
      • by tmosley (996283)
        Unless the "water" was in the form of oxygen and hydrogen in minerals.
      • by mark-t (151149)
        Where would it boil away to, exactly? AFAIK, Earth's gravity is strong enough to hold onto water vapor without it getting into space.
        • by Anonymous Coward

          A few things:

          1) When the Earth was being formed, it was smaller than it is now (not having been fully formed yet, and all). So, the gravitational field was lower. Lightweight stuff would have had a much easier time escaping, especially with the nice hot solar wind blowing.

          2) Given the lack of our current atmosphere, the direct exposure to solar radiation would have been intense enough to actually separate the water out into its basic elements. The separated hydrogen and oxygen would have been even lighte

    • I mean, if it could form on comets or asteroids, why could it not have formed right here on Earth the same way it forms elsewhere? Why is there such a predisposition to the notion that water must have come from somewhere else?

      Earth, in its early years, was a molten ball of rock and metal. Pretty much all the junk that's swirling around in the mantle today, plus the stuff in the crust that floated to the top. Think Jupiter's moon Io, but bigger, and it eventually cooled off. Anyway, when a planet is that hot

    • Why is it that water had to come from elsewhere, exactly?

      The reasoning can be summed up in one word: Neon. There is almost none of it on Earth, although it is common elsewhere in the Universe, and was almost certainly common in the cloud that formed the Earth and Solar System. Neon has an atomic mass of 20. Water is 18. So when the Earth was young and hot, and didn't have enough gravity to hold onto its neon, it wouldn't have been able to hold onto water vapor either. Therefore the water must have arrived later.

      • by mark-t (151149)
        Wow... I actually understood that.

        One question remains, however... why did water arrive, but not any Neon?

        • One question remains, however... why did water arrive, but not any Neon?

          The early Earth lost both its water and its neon because it was very hot from massive collisions. For instance, the collision that is believed to have formed the moon was enough to liquify the entire planet. But comets and asteroids were never hot. So they lost their neon (which is a gas at even very low temperatures) but didn't lose their water because it was frozen.

        • by M8e (1008767)

          1. There is a lot more of Hydrogen and Oxygen than Neon.
          2. Water have a feezing point of 273.15 K, while neon is 24.56 K(Under standard pressure, but it doesn't change much). This means that water can form a solid closer to the sun, and crash into things like Earth instead of just get blown away by solarwind.

  • That ball of acid and CO2 could really benefit from some H2O. So there's the new terraforming plan: paint a bullseye on Venus, and they'll come...
    • It always shocks me how casual people are with the idea of completely altering ANOTHER planet.
  • Ok, just to get it out of the way, here's the obligatory question: This happened millions of years ago! How is it news for nerds?

    p.s. anyone who answers this as if it were a legitimate question shall be dunked into a tank full of melted asteroids. :)

    • Ok, just to get it out of the way, here's the obligatory question: This happened millions of years ago! How is it news for nerds?

      p.s. anyone who answers this as if it were a legitimate question shall be dunked into a tank full of melted asteroids. :)

      Because it's Slow-News-Day Sunday on Slashdot. **holds nose for dunking**

  • We call Earth a water planet. It seems preposterous that a bunch of rocks could bring in enough water to fill Earth’s lakes, rivers and oceans.

    Yet Earth, in terms of its overall mass, is 0.06% water [nature.com]. With about 70% [usgs.gov] of its surface covered in water, Earth is considerably drier than it appears.
    • Why, thank you very kindly for that link. And here's a link expressly made just for you... http://don-brock.blogspot.com/2009/02/why-do-people-insult-other-people.html?m=1 [blogspot.com] ;-)
    • by Brain-Fu (1274756)

      Your statement does not contradict what the article is saying. Did you intend it to?

      Everything heavier than hydrogen is cooked within and then ejected from a star. Stars are where atomic fusion occurs, you see.

      The water droplets shoot out from the poles of the star. They are perpendicular to Earth's orbit. So, those droplets wouldn't have landed directly on the Earth. They first would have frozen out in the void of space, and collapsed into one another due to their mutual gravity, forming big icy rocks

  • I once had a quick-link to a paper on the topic – but there is a fringe of geologists that speculate how water could from from liberated oxygen and hydrogen deep within the mantle. Basically, the earth 'sweating' water from the core, outward.

    It hard to imagine (statistically) that all of earth's water... such a huge volume, was from icy balls (comets) striking the planet.....

  • The ratio of water to rock in an asteroid is lower than the ratio of water to rock on Earth by approximately a whole fucking lot. So this is as idiotic as it sounds. What do scientists think asteroids are structured like, water balloons? Let's see....how else is water made. Oh yeah, expose Hydrogen to heat in the presence of Oxygen. Naw, where would hydrogen and oxygen ever come together and get hot around a planet in space? That's just silly.
    • by Anonymous Coward

      It sounds like you formed a conclusion before reviewing the evidence.

      Do you realize that the Earth is less than one tenth of one percent water by mass? Plenty of asteroids have more water than that.

      Also, during the formation of the Earth, the region anywhere under 4AU from the Sun was so hot that water could not condense. Direct exposure to solar radiation of that intensity actually makes water break down to its basic elements, so you wouldn't get any as a core part of the planet. A bit further out, howe

  • Whatever. We got the water- Mars can suck dust. Take that you funny looking green guys!

  • At first I read that as "Android crashes" and wondered if only there were some way to harness the power of Windows crashes as well....

  • The summary sums it up better "The results contradict prevailing theories, which hold that most of our planet's water originated in the outer solar system and was delivered by comets or asteroids".

    Whoever wrote 'Asteroid Crashes Likely Gave Earth Its Water' as a news headline should not be allowed to write headlines anymore.

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