Stanley Miller's classic "primordial soup" experimental setup,
with a simulated ocean, lightning and broth
of hydrogen, methane, ammonia and water.
Posted on 04/08/2005 7:39:14 AM PDT by PatrickHenry
A new University of Colorado at Boulder study indicates Earth in its infancy probably had substantial quantities of hydrogen in its atmosphere, a surprising finding that may alter the way many scientists think about how life began on the planet.
Published in the April 7 issue of Science Express, the online edition of Science Magazine, the study concludes traditional models estimating hydrogen escape from Earth's atmosphere several billions of years ago are flawed. The new study indicates up to 40 percent of the early atmosphere was hydrogen, implying a more favorable climate for the production of pre-biotic organic compounds like amino acids, and ultimately, life.
The paper was authored by doctoral student Feng Tian, Professor Owen Toon and Research Associate Alexander Pavlov of CU-Boulder's Laboratory for Atmospheric and Space Physics with Hans De Sterk of the University of Waterloo. The study was supported by the NASA Institute of Astrobiology and NASA's Exobiology Program.
"I didn't expect this result when we began the study," said Tian, a doctoral student in CU-Boulder's Astrobiology Center at LASP and chief author of the paper. "If Earth's atmosphere was hydrogen-rich as we have shown, organic compounds could easily have been produced."
Scientists believe Earth was formed about 4.6 billion years ago, and geologic evidence indicates life may have begun on Earth roughly a billion years later.
"This study indicates that the carbon dioxide-rich, hydrogen-poor Mars and Venus-like model of Earth's early atmosphere that scientists have been working with for the last 25 years is incorrect," said Toon. In such atmospheres, organic molecules are not produced by photochemical reactions or electrical discharges.
Toon said the premise that early Earth had a CO2-dominated atmosphere long after its formation has caused many scientists to look for clues to the origin of life in hydrothermal vents in the sea, fresh-water hot springs or those delivered to Earth from space via meteorites or dust.
The team concluded that even if the atmospheric CO2 concentrations were large, the hydrogen concentrations would have been larger. "In that case, the production of organic compounds with the help of electrical discharge or photochemical reactions may have been efficient," said Toon.
Amino acids that likely formed from organic materials in the hydrogen-rich environment may have accumulated in the oceans or in bays, lakes and swamps, enhancing potential birthplaces for life, the team reported.
The new study indicates the escape of hydrogen from Earth's early atmosphere was probably two orders of magnitude slower than scientists previously believed, said Tian. The lower escape rate is based in part on the new estimates for past temperatures in the highest reaches of Earth's atmosphere some 5,000 miles in altitude where it meets the space environment.
While previous calculations assumed Earth's temperature at the top of the atmosphere to be well over 1,500 degrees F several billion years ago, the new mathematical models show temperatures would have been twice as cool back then. The new calculations involve supersonic flows of gas escaping from Earth's upper atmosphere as a planetary wind, according to the study.
"There seems to have been a blind assumption for years that atmospheric hydrogen was escaping from Earth three or four billion years ago as efficiently as it is today," said Pavlov. "We show the escape was limited considerably back then by low temperatures in the upper atmosphere and the supply of energy from the sun."
Despite somewhat higher ultraviolet radiation levels from the sun in Earth's infancy, the escape rate of hydrogen would have remained low, Tian said. The escaping hydrogen would have been balanced by hydrogen being vented by Earth's volcanoes several billion years ago, making it a major component of the atmosphere.
In 1953, University of Chicago graduate student Stanley Miller sent an electrical current through a chamber containing methane, ammonia, hydrogen and water, yielding amino acids, considered to be the building blocks of life. "I think this study makes the experiments by Miller and others relevant again," Toon said. "In this new scenario, organics can be produced efficiently in the early atmosphere, leading us back to the organic-rich soup-in-the-ocean concept."
In the new CU-Boulder scenario, it is a hydrogen and CO2-dominated atmosphere that leads to the production of organic molecules, not the methane and ammonia atmosphere used in Miller's experiment, Toon said.
Tian and other team members said the research effort will continue. The duration of the hydrogen-rich atmosphere on early Earth still is unknown, they said.
Excellent. I hope you keep a link to that in your homepage. It's a subject that comes up often.
Excellent post and definitely worth a bookmark ;)
Don't get too far ahead of yourself... ID'ers get "bashed for their lack of scientific proof" because they claim to *have* "scientific proof" (actually "proof" is a poor choice of words on your part, try "support" or somesuch), but turn up empty-handed when asked to show it.
The ID movement claims to be a science-based one. The point is that contrary to their claims, they *aren't*. And if they're relying only on the kind of "untestable" declarations you produced by editing the earlier remarks, then indeed, they *do* deserve to be "bashed for their lack of" scientific support or evidence for their position, especially when they want to shoe-horn it into *science* classes in schools.
Saying, "No one can disprove my belief because it can't be tested in any way" is *NOT* the same thing as "scientific support" for that belief, and people rightly deserve to be roasted if they try to misrepresent the former as the latter, as the "ID'ers" all too often do.
Furthermore, two of your three examples mention "God", which the "ID'ers" tie themselves in knots attempting to claim they are *not* invoking as the hypothetical "designer".
This is, of course, one of the Fundamental Questions(tm).
It is often more succinctly stated as, "why is there something instead of nothing?"
However, it's thought-provoking to turn the question on its head: Why would there be "nothing" instead of something? *Can* there be "nothing"? "Nothing" is at best an imaginary abstract concept, but does it, can it, actually reflect any possible mode of reality or existence?
The only state *know* is possible is "something" -- perhaps there is no other possible alternative.
That was a pretty pathetic response.
Congratulations, you've just demonstrated that you haven't a clue how science actually works, since you are completely unaware of the reasons that scientists employ such phraseology.
Hint: It has nothing to do with being "mere speculation", and everything to do with the awareness that empirical knowledge, no matter how solid, is provisional. That same kind of provisional knowledge got us successfully to the Moon and back.
Come back when you understand the topic enough to be able to critique it sensibly.
It depends on the beliefs of the observer. It's a variable. They need like minds to prove it.
Wow you don't know much about quatum physics either, I see. No, it doesn't "depend on the beliefs of the observer".
They've done studies on the "Jinx in the machine". They allowed balls to drop freely though pegs. Those who believed most of the balls would land on the left side of the machine got balls on the left side of the machine. Those who believed most of the balls would land on the right side got most of the balls on the right side of the machine.
"They" have, have "they"? Yeah, right, sure "they" have. You go right on believing that.
But for our amusement, feel free to try to provide citations to these "studies".
But... You yourself are "beginning research with an assumption" (the assumption that there is a God, *and* that it was necessarily directly involved in the processes being examined).
I'm trying to figure out how that doesn't make you a hypocrite.
And is it really your contention that people who (*ALLEGEDLY*) start with a presumption different from yours are completely incapable of presenting you with anything you might possibly learn from? Because that seems to be the bizarre position you're putting forth.
Finally, what if they happen to be *right* in that assumption after all, and thus are in a better position to find the answers than you yourself are? Or are you so certain of the answers already that you don't need to pay attention to alternative possibilities (in which case why bother at all)?
Well, hell, who can argue with *that* ironclad and well-reasoned rebuttal?
If you thought that was a valid challenge, you're mistaken.
Hey PatrickHenry, witness the "moving of the goalposts" right here.
How about 700 million years in microseconds?
But... You yourself are "beginning research with an assumption" (the assumption that there is a God, *and* that it was necessarily directly involved in the processes being examined).
I'm trying to figure out how that doesn't make you a hypocrite.
Two differences in this case:
One, I am supposing an opposite to what is being presented.
Two, I do not claim to be a foremost authority on the subject, I am merely debating my opinion with another.
"And is it really your contention that people who (*ALLEGEDLY*) start with a presumption different from yours are completely incapable of presenting you with anything you might possibly learn from?"
You mis-read. I do not like to study from people who have AND presumptions on their subject. I'll listen, sure. But that does not mean I will buy what they offer as true knowledge.
"Finally, what if they happen to be *right* in that assumption after all, and thus are in a better position to find the answers than you yourself are? "
I don't know, that whole "imperical thought" thing would nag me. If we all agreed, noone would be thinking. Quite frankly, I'd rather think than have all the answers.
You should have read the post I was responding to.
What would you accept as evidence?
By what I said, and by what I imply: God is the Truth of all things. "Truth" is a name for God.
Saying one exists does not make one THE Truth. As you state with " But that's true exactly like "'JennyP exists' is a statement that accurately describes reality."
Your existance PROVES existance, but it does not make YOU existance. What God is is the origin of all things. God is the perfect form that Plato spoke of.
While your latter statements are also correct, they are not what I meant by my statement.
A photograph would be good. ;^)
Well here is diagram of something that really doesn't exist.
Why do you think it more likely that things came about by chance rather than design?
I'm shocked. Shocked!
Thanks for the honest input. Again, it's nice talking to people who respond nicely.
I did have another thought though while I was away from the computer today:
Would it be easier to guide reactions at lower temperatures? I forget the enitre thought process that lead to this idea, but thats the conclusion of it.
Any help working it back into coherenace would be appreciated.
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