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Comets Probably Seeded Earth's Nitrogen Atmosphere
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."
Space.com brings word of a team using new evidence is suggesting that the mysterious 1908 event in Tunguska was a comet despite a team two years ago arguing it was an asteroid. 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. 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 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?
My work here is dung.
Nitrogen came from comets, and methane came from Uranus.
The article notes that the ratio of the nitrogen isotopes matches what is in the earths atmosphere. It seems to me, that just makes it possible that the comets are a significant source of the nitrogen on Earth. It is also possible that the nitrogen in the comets and in the atmosphere came from a common source.
Duh, it reproduced once it arrived on Earh.
In addition to creating an atmosphere on earth, comets may also have seeded life.
Everyone knows nitrogen is here because of the Holy Sauce dripped from His Noodly Appendage.
Astronomers renamed that planet in 2020 to stop that stupid joke once and for all.
Oh. What's it called now?
Urectum
Conscience is the inner voice which warns us that someone may be looking.
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).
Free Software: Like love, it grows best when given away.
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)
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
Sig Battery depleted. Reverting to safe mode.
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?
"Empathise with stupidity, and you're halfway to thinking like an idiot." - Iain M. Banks
>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.
Infinite time means everything that can happen, will. You being you is absolutely incidental. You do not exist.
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?
"I don't know, therefore Aliens" Wafflebox1
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.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
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.
Sheesh, evil *and* a jerk. -- Jade
Gold? That would be from a supernova.
There's nothing like $HOME
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."
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?
Blasphemy is a human right. Blasphemophobia kills.
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.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
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.