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.
And you'll find the organic molecules they use are just as complicated, involved, and delicate as those in the Krebs Cycle, so the initial point still stands.
Then why do the PatrickHenry's and VadeRetro's of this website argue so vehemently (might I say, with religious fervor) against creation, God, or even ID? Why don't they just say, "ToE doesn't have an answer for the origins of life, so it may be correct that it was created by some intelligence."?
My guess is that the answer lies very much in the realm of an internal fear "so great that it cannot be acknowledged".
"Disorder is not what entropy is to chemistry."
I don't want to argue semantics, but in engineering school, we called increased disorder in a mechanical system entropy as well. We may have hijacked the word, though...
You are refering to the Krebbs cycle, which is a metabolic pathway, like many, existing in currently living things. These metabolisms are the products of evolution, not biogenesis. Yes, organic materials can be the products of living things. Such organic compounds can be synthesized in the lab, too. That is a really big study - the synthesis of natural products without the use of living things. However, biogenesis requires the exploitation of naturally occurring organics. Invoking a currently existing metabolic pathway presumes such a pathway was the product of biogenesis. That is not necessarily the case and indicates, as you have mentioned, that certain organics found in the complicated metabolic paths of even simple cellular organisms present today could not have existed during biogenesis. This is also a clear indication that whatever the first life forms were, they are not comparable to today's cellular life forms.
Well, there's precedent for that: the Bible says that God has always existed. He has no beginning and no end - but, of course, it would require a lot of faith to believe that space/time, er, I mean God, has always existed. I mean, how could one set up an experiment to test whether space and time have always existed? I don't see how it could be tested! Therefore, since we cannot empirically test whether space and time have always existed, we, being the sciencists that we are, MUST reject the theory that the universe has always existed (and God as well).
So, now I'm left with the question: Why is there anything? Why not nothing?
If the materials on Titan could be studied in greater detail, I would not be surprised to find a great variety of organics existing in the brew up there. I'd bet a dollar that we would find some extremely intereting chemical species, some of which may be substances though only related to metabolic processes. A month with an organic analytical lab on the surface would yield some wildly unexpected results.
I'm pretty damn sure they said just that and not only once but several times.
My guess is that the answer lies very much in the realm of an internal fear "so great that it cannot be acknowledged".
Fear? No, we just don't think that an "Intelligent Designer" is necessary to explain how life developed (or originated).
"And you'll find the organic molecules they use are just as complicated, involved, and delicate as those in the Krebs Cycle, so the initial point still stands."
This point cannot be proven just because you say it is so. It definitely would take a chemist who has knowledge in this subject well beyond my own to prove this one way or another.
You must not read many Crevo threads. We state the obvious all the time. Here's one: The Theory of Evolution, just like the Theory of Gravity, does not address the origin of life.
"Therefore, since we cannot empirically test whether space and time have always existed, we, being the sciencists that we are, MUST reject the theory that the universe has always existed (and God as well)."
You cannot reject the theory that the universe has always existed simply because you cannot test it at this point in time. You definitely cannot prove the universe has always existed just as you cannot prove that the universe appeared one day using todays best scientific methods.
That does not invalidate the possibility that the Universe has always existed. Like I said the laws of thermodynamics state that no energy or matter can be created or destroyes. If this law is correct, the only possibility is that the universe has always existed.
If you can disprove the laws of thermodynamics you may have a foot to stand on, otherwise the universe must have always existed.
Yes, but we (the pro-evolution regulars) don't like to say it more than once a thread, because such repetition is exceedingly tiresome. Unfortunately, no amount of repetition will ever be enough. However, here's one more posting of Darwin's take on the subject:
There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone circling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.Source: Origin of Species. (Last sentence of last chapter)
Thanks for your replies, in advance.
That is quite a fair statement, and I did not mean to imply a perfect analogy. I do realize of course that when I fix my 1967 Camaro I am not overcoming the second law of thermodynamics. On the contrary, I am "opening the system", and introducing an element (me) which adds order. The point I was making was that, in general, chaos does not breed ordered complexity. It really was meant to be taken as that. In fact, even in my analogy, there is a real possibility that an arrangement of components into the aforementioned 57 Chevy would occur. I just maintain that it is extremely unlikely - and this is the heart of my analogy. Follow me for a moment in a silly supposition. I suppose one could make the argument that the universe as we know it was created yesterday in a huge explosion of matter, which randomly placed all of the atoms in my brain (and I have been accused of having fewer than normal a time or two) into place. Suppose this explosion also randomly created chemicals and synapses (pardon my obvious lack of understanding of brain function) and therefore implanted all the memories I have. These memories are therefore false - but by chance, they match the false memories of my friends and family. I can't say that isn't possible, if all of the primordial legos were there. I just think it is unlikely. Now what I am getting at in that last, very obtuse point, was that I don't find the complexity of any conceivable primordial cell to be likely to have been generated by random processes. I do believe that cells are composed of matter, and perhaps some day we shall be able to build them from scratch. It doesn't change the fact that I believe it more likely that life on Earth was as a result of Intelligent Design. But then again, a staunch materialist will argue that my explanation, an Intelligent Designer, is in their estimation, more unlikely. I can understand, and as a person who considers himself pretty skeptical in nature, respect their point. Ultimately, I have other reasons for my beliefs, some I would characterize as objective, others not. Perhaps someday we will have an opportunity to discuss them in another setting. Lastly (and this is not directed at you, stremba), I do wish that the believers in these forums would be a little more careful about condescension and name-calling. You aren't exactly winning any for our side, ya know? As Christians, please hold yourself to a higher standard than that. Do I feel when I read the pro-evolution posts, some are insulting? I sure do. When I am insulted, is my first reaction to want to kick somebody's head in? Yup. But then I think, "hey, here is a person that I believe God created and loves as much as me. Maybe, if I respect their line of thinking, and argue logically and amicably, we can learn from each other." After all, their comments often help me sharpen my own arguments at the very least.
If life here is a zillion-to-one chance, why are there so many different species of plants and animals?
The second part has nothing to do with the first. (Sounds like a push poll question.) The diversity is explained by inexact reproduction and differential survival.
Do plants and animals share a common ancestor?
Yes. The cladistic structure including both show at least one common ancestor.
All living things take in "nourishment" and excrete "waste". Why?
It't actually due to the second law of thermodynamics; one cannot extract all the energy in food. Something is left over.
What could possibly explain the origin of the "instinct for survival"? Doesn't this imply a priori knowledge?
There is no "instinct for survival." Species that do a poor job just die out. It's like the Texas Marksman joke.
Is a "quantum psychic" someone who tells you your future in discrete packages? : )
"You cannot reject the theory that the universe has always existed was designed by an intelligence simply because you cannot test it at this point in time. "
"You cannot reject the theory that the universe has always existed God exists simply because you cannot test it at this point in time."
"You cannot reject the theory that God is the intelligent designer of the universe has always existed simply because you cannot test it at this point in time."
I'll remember that the next time I see ID'ers bashed for their lack of scientific proof, lol!
Thank you, Patrick. Quite interesting, Darwin's parting words from OOS.
The embarrassing answer is that for hundreds of millions of years the world was gay. This was a terrible time for evolution, and the fossil record is quite pornographic. Not only that, but reproduction was very difficult. It's believed that the dinosaurs died out as a result. Then a miracle happened, and females appeared. The rest is history.
[Source: Secret archives of Darwin Central.]
Consciousness is a miracle. If you reply, "Consciousness is an illusion; I'm really a machine that simulates consciousness," then you are contradicting yourself by asserting that there is an "I".Consciousness is not an illusion. I am a machine that achieves consciousness. Consciousness is the work-product of my brain. You are committing the fallacy of composition if you think that consciousness must be something that's "injected into" a machine. Consciousness is an emergent property of a functioning brain in a functioning human body. It's really much simpler than you're trying to make it. Just drop that fallacy and everything falls into place.
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