Comets Probably Seeded Earth's Nitrogen Atmosphere 110
KentuckyFC writes "One of the biggest puzzles of astrobiology is the origin of the Earth's oceans and atmosphere. One favored theory is that our water is the leftovers from a bombardment of comets early in Earth's history. But the ratio of hydrogen and deuterium in the oceans doesn't match the ratio in the four comets measured so far (Halley's, Hyakutake, Hale-Bopp and C/2002 T7 LINEAR). Now a new analysis of the ratio of nitrogen-14 and 15 isotopes in these comets and on Earth places new limits on how much of our environment could have come from comets. On the one hand, the astronomers who did the work say that no more than a few percent of Earth's water could have come from comets. But on the other, they say that the ratio of nitrogen isotopes in these comets almost exactly matches the ratio in Earth's atmosphere. That suggests that while Earth's oceans must have come from somewhere else, Earth's early atmosphere was probably seeded by comets."
Tunguska Clouds an Indication? (Score:5, Interesting)
Space.com brings word of a team using new evidence is suggesting that the mysterious 1908 event in Tunguska was a comet [space.com] despite a team two years ago arguing it was an asteroid [slashdot.org]. The comet theory does explain the odd phenomenon of the night skies being lit up for several nights following the event all across Europe--about 3,000 miles away. Researchers believe this points to a comet because when the space shuttles launched today pass through the atmosphere they cause or improve the formation of noctilucent clouds [wikipedia.org]. These clouds are so high up (55 miles) they are only made of ice particles and they are only visible at night which gives researchers reason to draw the conclusion that the 300 metric tons of water vapor that the shuttle pumps into the Earth's thermosphere must likely indicate that the thing that hit was loaded with water or ice. This would make it a comet and not an asteroid. This--of course--raises new upper-atmosphere physics problems for the Tunguska event but explains the strange phenomenon over the skies of the world following it. You may remember analysis of Lake Cheko last year [slashdot.org] in an effort to better understand what happened.
Well, if every comet that hit earth dropped off a little bit of water--even in the form of noctilucent clouds ... it'd take a while but is it really so far fetch to think that ultimately all our water and atmosphere are extra-terrestrial? Probably unlikely but over a long enough time, who knows?
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moves on a giant space turtle.
I had wondered where Gamera has been.
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I have often wondered if our iron core was some alien races way of seeding the Earth, because without the iron cor
Re:Tunguska Clouds an Indication? (Score:5, Informative)
The point is that the isotope abundances of the oceans don't match the only four comets that have been observed precisely enough. H20 and HDO are easily distinguished from each other, and deuterium (the "D" in HDO) is quite stable so the isotope abundances shouldn't have changed. We've only measured 4 comets, though, so perhaps other comets more closely resemble our oceans.
Coincidentally, I attended Dr. Goldblatt's fascinating talk at the Fall 2008 AGU conference where he showed that the faint young sun paradox [dumbscientist.com] could be mitigated by a higher nitrogen pressure in the primordial atmosphere. Someone in the crowd (a Slashdot user, perhaps?) answered my question about experimental constraints on this pressure by saying that current research involving "raindrops" might produce a constraint soon.
This paper seems like it should be relevant, but I've yet to see a direct connection. If anything, the disparities in the isotope abundances between 15N/14N and D/H seem to imply their origins are (at best) only loosely connected. But unfortunately the guy who shouted "raindrops" didn't have a microphone and he was across a crowded lecture hall, so I don't have the foggiest idea what he meant. Maybe "raindrops" was a brief reference to the "enstatite chondrites" on page 7 of this new paper (the context seems similar, at least). However, Javoy's paper was published in 1986 and my mysterious benefactor definitely said the research was currently underway. Plus, the topic at the time was the total pressure of nitrogen, not the isotope abundance...
Anyone who knows about this subject, please enlighten me!
Re:Tunguska Clouds an Indication? (Score:4, Interesting)
The May issue of scientific american had an interesting article about the slow loss of atmospheric gasses into space...
how-planets-lose-their-atmospheres [scientificamerican.com] ...which suggests that the early earth had a lot more water and a denser atmosphere. It also, obviously, had a lot more CO2, vast quantities of which are now locked up in the form of rock (limestone) and organic matter.
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Well, if every comet that hit earth dropped off a little bit of water--even in the form of noctilucent clouds ... it'd take a while but is it really so far fetch to think that ultimately all our water and atmosphere are extra-terrestrial? Probably unlikely but over a long enough time, who knows?
I think that the point of the summary is that if the water were primarily from comets then we'd expect the water on earth to have a similar ratio of deuterium to hydrogen to that found in comets. Since it doesn't, either most comets out there have a very different composition from the ones we've observed, or the earth's water must have a different source. Of course the water is extraterrestrial in origin (like everything else), but it looks as if we didn't get it from comets.
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IANAAP/AB:
IT seems pretty clear the water we have today didn't come from the type of comets we see NOW. However, I don't see how it says anything about what sources of water ice were like shortly before or after the sun spooled up it's furnace, and gradually blew the remnant dust to the edge of the solar system. Why couldn't the proto-Earth cloud have captured large volumes of water ice before the Sun fired up?
As for the Nitrogen. That the isotope ratios in the comets and on the Earth agree, means to
Nitrogen came from comets . . . (Score:4, Funny)
I'm sorry Fry, but... (Score:3, Funny)
Oh. What's it called now?
Urectum
But there's soooo much water on (and in) Earth... (Score:1)
... how could anyone reasonably think that comets brought it all?
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I was under the impression that the Earth's water precipitated out of the original accretion disc as the early earth cooled. That is, everything accreted, and then as the molten rock and surrounding gases cooled to form a sold surface, the water that became the Earth's oceans and such also cooled and condensed, and basically rained down on the planet over time.
Has there been some reason to doubt this? i.e. evidence that refutes this hypothesis?
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It's easy (unless you're a fundie) to understand where the heavier elements and such come from, since they melt at high temperatures.
But water and the "stuff" that are gases at STP are volatile. So... what kept them "near" the earth while it was very hot (way past the boiling point of waster) and small and accreting? There wasn't enough of a magnetosphere to protect any atmosphere.
Could it be that H2O, N2 and O2 were created from the decomposition of very hot rocks?
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By the time that you've got your rocks molten, their water, CO2 and ammonia (nitrogen in it's most-likely protoplanetary form) would have pretty-much fucked right off. At the time that the Moon was formed (giant impact hypothesis, still the best one running), much of the depth of the mantle was temporarily ejected into low proto-Earth orbit, and at sufficient temperatures that significant amounts of such volatile ions as s
Get up to date on planetary formation theory (Score:4, Interesting)
This is a rapidly evolving field and I don't pretend to have more than a very casual reader's knowledge - but think of it like this. The Earth is, in cosmic terms, a small planet. Its water layer is a minute fraction of its mass. In terms of the solar system as a whole, the percentage of the available water on Earth is extremely small.
It is possible, but not certain (Score:5, Insightful)
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What correlation? (Score:2)
This is a comparison, not a correlation.
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Nobody's saying it is, the article is putting an upper bound on the amount of water and nitrogen that could come from cometary ices. They comment that this leaves the door open for a substantial amount of nitrogen from comets, but only a miniscule amount of water.
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What comet63 said. Large primoridal clouds of hydrogen are easy to understand, and oxygen is enough lighter than carbon that it could occur early on in stellar formation, I'd think (IANAAP, IMBFOS). So I can imagine large clouds of the two gases igniting in the early part of our planetary history, with enough being captured by our own gravity well to compress and become water. The rest, as they say, is geography. Add lots of the slightly less reactive nitrogen and you'd get something approaching the mixt
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The comets may have seeded life. (Score:2, Interesting)
Uhmmm... (Score:2)
Comets Probably Seeded Earth's Nitrogen Atmosphere
So we've been breathing space spooge all along?
Well THAT explains a lot...
No, no (Score:2, Funny)
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Dude I am pretty sure it's potassium in the Holy Sauce, in described in the Battle of Bolognese.
http://links.nephron.com/nephsites/adp/pot.htm [nephron.com]
Obvious? (Score:1, Informative)
http://www.space.com/scienceastronomy/astronomy/milkyway_water_010412.html [space.com]
That seems to make some sense. (Score:2, Interesting)
My guess is that earth started out as a (not -so-giant?) gas giant and bled of most of it's original hydrogen. If that's even vaguely true, then there's little likelihood that the isotope mix would be anywhere near what's in comets.
I'm guessing that the deuterium mix is much higher than in comets (because deuterium, being heavier than hydrogen, is less likely to bleed off).
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Are you an astronomer? I ask only because you're modded +4 Interesting. But, in your comment you say: "My guess is..." and then "I'm guessing that..." What makes you think that your two guesses are in any way valid? Maybe this (my) comment is directed more at the mods than you because if you were not modded up so much I'd gloss over your comment.
Re:That seems to make some sense. (Score:4, Insightful)
This is
Even more important experts can and should be questioned. People outside the field can give suggestions and should criticize experts if they cannot justify their point of view. The only times we get a group of people that think they cannot be questioned by outsiders... they are usually wrong.
And what are your credentials? Modding expert? Modding consultant?
By the way I am an astronomer by training... Grandparent has a good point.
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The only times we get a group of people that think they cannot be questioned by outsiders... they are usually wrong.
What does government have to do with this discussion?
Determining the origins of .... (Score:2, Flamebait)
just about anything in the universe, and specifically various aspects of this planet, is becoming more like numerology than anything else. Case in point:
But on the other, they say that the ratio of nitrogen isotopes in these comets almost exactly matches the ratio in Earth's atmosphere. That suggests that while Earth's oceans must have come from somewhere else, Earth's early atmosphere was probably seeded by comet.
Any pattern they find seems to make scientists believe something is true, no matter how improbable. Scientists are only seeing what they want to see in this data. Despite this method of guessing based on simply "interesting patterns" and hoping they are right, these very same people consider taking on faith what the Holy Bible says about the origins of the
Re:Determining the origins of .... (Score:4, Insightful)
>method of guessing based on simply "interesting patterns"
That would be the SCIENTIFIC method (or at least the first part of it), the source of all scientific advancement since whenever.
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Carefully note the words "probably" and "suggests."
In other words, nobody has claimed anything is "true." They noted an interesting pattern and thought about what it could mean. Now they'll try to devise experiments to test that hypothesis.
Contrast this with theological reasoning: "the bible says so, therefore it is true. End of discussion."
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Contrast this with theological reasoning: "the bible says so, therefore it is true. End of discussion."
Scientists are free to prove the Bible right/wrong. The problem is they do not. Why do they not even try? Are they afraid that they will prove it right?
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How do you prove a story wrong? Particularly a vague, self contradictory story? Many of the things we know about the world appear to contradict what's in the bible. Bible advocates either twist bible stories so the apparent contradiction goes away, or they simply ignore the science.
I notice you didn't even try to reply to the content of my post, but rather cooked up some extremely questionable claim that you stated as fact, instead. Typical.
Wood to Gold (Score:1)
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Not exactly a new theory: The Big Splash (Score:5, Interesting)
The theory of comets as a source of water was also published in 1990, by Louis A. Frank.
Not exactly your average crack-pot scientists, Frank was the designer of something like 13 payloads on various launch vehicles in the 80s and 90s.
Frank posits that that small comets still hit the moon and earth almost daily, delivering water virtually every day. These small comets are more like fluffy snowballs, and are small enough not to have much if any radar signature, but their effects upon impact with the atmosphere are visible from above.
http://en.wikipedia.org/wiki/The_Big_Splash_(book) [wikipedia.org]
Excerpt from The Big Splash
by Louis A. Frank with Patrick Huyghe
Published by Birch Lane Press, 1990.
ISBN 1-55972-033-6
http://smallcomets.physics.uiowa.edu/blackspot.html [uiowa.edu]
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No, it isn't a mystery.... Gen 1:1 In the beginning...
That's the Cliff's Notes abstract. For the expanded version, start with the Big Bang and use physics.
God is the name I give to the Universe and all her natural laws.
Science is my prayer. I keep my logical integrity intact by understanding that the converse is not also true.
Yes, it is a mystery (Score:1, Insightful)
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Yes, you said it, they are fools. Anybody who thinks they know how the universe was created based on a few pages they read in some book that someone else wrote is a drooling idiot. Strict agnosticism is the most rational and logical theological position.
Furthermore your weak and unrelated hypothesis doesn't even begin to answer my question, how were the heavens and the earth created from nothing?
Face it, neither modern science nor biblical creation myths provide a satisfactory explanation as to why all of t
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I'm confused about why you're replying to a statement on agnosticism with a page that describes god as a person or being in fiction.
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Who is this God character? How did he create the heaven and the earth from something without form, out of a void? There are obviously some details missing and I demand a refund for this explanation of the universe you have sold to humanity.
He's the programmer who created the Matrix. They never did get all the bugs out of the "dirt" subroutine. I'd give you more information, but unfortunately the code is closed source.
Re: No, it isn't a mystery.... (Score:3, Funny)
Dude, your passage doesn't actually say anything about where the ocean and atmosphere came from. It just claims that God pushed some water around a bit.
If you're going to vest your credibility in a mythological text, you should at least read it carefully.
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No, it isn't a mystery.... Gen 1:1 In the beginning God created the heaven and the earth. Gen 1:2 And the earth... and God saw that it was good.
Yeah, all right, what really happened? Tell the truth.
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Let's see. first of all, it's entirely possible that some guy's personal world flooded, wiping out his neugbours and that he and his livestock escaped becase he happened to have a boat. Indeed, statistically, it must have happened often. I think the Epic of Gilgamesh has a somewhat similar event.
The solar wind is hydrogen nuclei, and going much faster than 33000 mph, but it's VERY VERY thin. I doubt the total amount impacting on the Earth's magnetic field in a year would be enough to raise sea levels a mill
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There's a great many people trying to make God go away. Kinda sad, really. No one tries to make Buddah go away, or discount Ra, or dispute Karma.
Just to point out, everyone who has ever taken the moral high ground with me based on religion, or anyone who has ever tried to shove religion down my throat, or sell it to me from my doorstep, have all worshiped the Christian god. I'm counting Muslims among these people as well, Islam is basically a breakaway Christian sect. I've never seen a Buddhist running around with an AK looking to kill anyone who doesn't believe in Buddha, and I haven't heard of any Egyptian campaigns, or crusades if you will, to
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I keep going over the proof for Noah's flood. It's not as far-flung as it sounds if you actually RTFM. It calls for a number of animals that would fit in a rowboat- it doesn't have to be millions. And it doesn't have to be a full world, either: Rome 'taxed the world' and I'm certain they didn't get New Jersey.
What? Considering there are thousands of species of mammals, birds, amphibians and reptiles each. Plus 100,000s of species of plants and millions of species of insects it must be quite a large row boat. No they could not have evolved suddenly in the last few thousand years, into the multitude we see today.
So here's the question.
What *actually* happens when the poles reverse and the Van Allen (etc) belts come down for a short time? The solar wind, largely H3 I'm told, touches an oxygen-covered surface at 33,000mph. So hot hydrogen..on oxygen...rain?
Well the Van Allen belts will dissipate presumably dumping some charged particles in the atmosphere. The reduced magnetic field will allow more solar wind and cosmic rays to hit the atmosphere. But conside
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Then Eve went into the orchard, and Satan talked her into trying a bite out of the tree of life. And then she talked Adam into a bite.
Then they fucked, and Eve went down to the river to bathe.
God saw Adam cowering behind a bush and said "WTF???" And Adam said "er, uh, um" and God said "Damn it, you ate that apple, didn't you? Then you fucked her, didn't you?"
And Adam said, Uh, yes sir, I'm sorry..."
And God said "Ok, whered the bitch go?"
And Adam said "she's down by the river washing up."
And God said "Oh shi
Ramen! (Score:2, Funny)
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Well, I'm glad you've got it all figured out, everybody in planetary formation research can go home now.
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I don't understand
Uh, huh. Well if you notice that the four inner planets are rocky and most are devoid of water. While the outer planets are made of gas and bigger maybe the material that formed the solar system was not evenly spread. The top reason for this is the sun is hot! Read an encyclopaedia [wikipedia.org].
from the ??? dept. (Score:2)
These stories (Score:1)
sure is taking a lot of faith (Score:2)
to believe in some of these theories....
Re:sure is taking a lot of faith (Score:4, Informative)
Faith in what? Have you read the paper behind this idea? It's full of assumptions and caveats that are explicitly laid out by the authors, pointing out that one can follow a particular thread of plausible but unproven argument, and suggesting ways of empirically testing it.
Ideas are tested by experiment and systematic, often quantitative, observation. That is the core of science.
Ideas are believed without question. That is the core of faith.
See the difference?
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That's the good thing about science: when the authors not only describe their conclusions, but also show all of the evidence they used to come to their conclusions, you can examine the evidence yourself and determine if you come to the same conclusion. You don't need to have faith in the authors when they give their reasons for their conclusions.
Seeded by comets? Or not... (Score:2)
they say that the ratio of nitrogen isotopes in these comets almost exactly matches the ratio in Earth's atmosphere. That suggests that while Earth's oceans must have come from somewhere else, Earth's early atmosphere was probably seeded by comets.
Or the nitrogen in the comets and the nitrogen in the Earth's atmosphere had a common origin which seems much more likely, the story title notwithstanding.
RE: One of the biggest puzzles of astrobiology (Score:1)