Posted on 09/12/2005 6:39:36 AM PDT by PatrickHenry
Using primitive meteorites called chondrites as their models, earth and planetary scientists at Washington University in St. Louis have performed outgassing calculations and shown that the early Earth's atmosphere was a reducing one, chock full of methane, ammonia, hydrogen and water vapor.
In making this discovery Bruce Fegley, Ph.D., Washington University professor of earth and planetary sciences in Arts & Sciences, and Laura Schaefer, laboratory assistant, reinvigorate one of the most famous and controversial theories on the origins of life, the 1953 Miller-Urey experiment, which yielded organic compounds necessary to evolve organisms.
Chondrites are relatively unaltered samples of material from the solar nebula, According to Fegley, who heads the University's Planetary Chemistry Laboratory, scientists have long believed them to be the building blocks of the planets. However, no one has ever determined what kind of atmosphere a primitive chondritic planet would generate.
"We assume that the planets formed out of chondritic material, and we sectioned up the planet into layers, and we used the composition of the mix of meteorites to calculate the gases that would have evolved from each of those layers," said Schaefer. "We found a very reducing atmosphere for most meteorite mixes, so there is a lot of methane and ammonia."
In a reducing atmosphere, hydrogen is present but oxygen is absent. For the Miller-Urey experiment to work, a reducing atmosphere is a must. An oxidizing atmosphere makes producing organic compounds impossible. Yet, a major contingent of geologists believe that a hydrogen-poor, carbon dioxide-rich atmosphere existed because they use modern volcanic gases as models for the early atmosphere. Volcanic gases are rich in water, carbon dioxide, and sulfur dioxide but contain no ammonia or methane.
"Geologists dispute the Miller-Urey scenario, but what they seem to be forgetting is that when you assemble the Earth out of chondrites, you've got slightly different gases being evolved from heating up all these materials that have assembled to form the Earth. Our calculations provide a natural explanation for getting this reducing atmosphere," said Fegley.
Schaefer presented the findings at the annual meeting of the Division of Planetary Sciences of the American Astronomical Society, held Sept. 4-9 in Cambridge, England.
Schaefer and Fegley looked at different types of chondrites that earth and planetary scientists believe were instrumental in making the Earth. They used sophisticated computer codes for chemical equilibrium to figure out what happens when the minerals in the meteorites are heated up and react with each other. For example, when calcium carbonate is heated up and decomposed, it forms carbon dioxide gas.
"Different compounds in the chondritic Earth decompose when they're heated up, and they release gas that formed the earliest Earth atmosphere," Fegley said.
The Miller-Urey experiment featured an apparatus into which was placed a reducing gas atmosphere thought to exist on the early Earth. The mix was heated up and given an electrical charge and simple organic molecules were formed. While the experiment has been debated from the start, no one had done calculations to predict the early Earth atmosphere.
"I think these computations hadn't been done before because they're very difficult; we use a special code" said Fegley, whose work with Schaefer on the outgassing of Io, Jupiter's largest moon and the most volcanic body in the solar system, served as inspiration for the present early Earth atmosphere work.
NASA's Astrobiology Institute supported this work.
I'm not ready invest my retirement dollar just yet, but it does seem a bit premature to say that tar isn't found in the geologic column.
Creationist question:
So, if scientists are successful at "creating" life, does that mean that that life came about because of "Intelligent Design"?
No. It would mean that life is such an easy step for organic chemistry that mere humans in a lab could do it. This would suggest (not prove) that -- contrary to the claims of some theologians -- such matters do not require the activities of a deity.
My point is that traditionally, theologians have marveled at the existence of life, and have frequently declared that its very existence is a miracle. Evolution may have happened naturally, many of them admit, but the initial appearance of life is such an impossible thing that it must be the miraculous act of a deity.
Many science-minded folk have suggested that this kind of argument is a trap, because if life is ever created in the lab (by mere men) then one of the central miracles which sustain many theological systems will be in jeopardy. The problem lies in relying on physical phenomena to justify faith.
Now, sensing that the "miracle" of life is soon to be created in a mundane lab by mere lab rats -- and not by gods and angels -- we can observe an almost instinctive moving of the goalposts. Now they'll demand an exact replication of the exact conditions on earth billions of years ago. And they'll then insist on perfect proof that those were indeed the young-earth conditions, etc. Endless objections will be raised. All of this is expected.
Every time an alleged "miracle" is demonstrated to be a natural occurrence, those who require miracles will squeeze and spin and dance as much as necessary to still find something they can claim is a miracle -- that is, an event not yet explained or demonstrated.
However, even if the first time the "non-life to life" trick is done, the conditions don't mimic those on the young earth, it will nevertheless be momentous, because the trick will have been done. Without supernatural intervention.
The question of our own consciousnesses or minds being natural or supernatural themselves is one of the questions left behind due to lack of interest.
True. But there will always be unanswered questions. Future generations of scientists will always have work to do. And theologians will always have mysteries. So I suppose threads like this will never end.
Is it okay to mention Dewey on this FRorum? Probably not, but he pointed out that many if not most of the burning questions and issues of the past have been left behind rather than resolved as our group development of philosophy has evolved to higher levels and left the old problems as essentially meaningless.
Not this geologist, particularly when you take the formation of the Moon into context. Ah, well...I've always been on the lunatic fringe, you know. ;)
I think that's because there is a lot of 'hard' science in this thread. As I am both mathematics and chemistry-challenged, I have been gritting my teeth reading this thread, worried that carbon-bonds and all sorts of organic chemistry that is way, way over my head was going to come gushing out beyond a wildcatter's dream.
Biology and evolutionary biology are actually just as 'hard' as organic chemistry--but everybody (even Creationists) think they 'understand' it because we are the subject matter.
...I was about to point the fallacy in this assumption using an analogy (Creationists love analogies) about asking guinea pigs to explain how the Skinner maze works--but no, let's not do that, it's a cheap shot :-)
An elegant statement, for "faith" is exactly that...a belief without physical evidence. And those who require physical evidence to justify their belief in a Deity are on very shaky ground. I believe Jesus said something to that effect to Thomas after the Resurrection (and yes, I know the passage...I'm just wondering if others are aware of it).
In the News/Activism forum, on a thread titled Calculations favor reducing atmosphere for early earth: Was Miller-Urey experiment correct?, PatrickHenry wrote:
" Every time an alleged "miracle" is demonstrated to be a natural occurrence, those who require miracles will squeeze and spin and dance as much as necessary to still find something they can claim is a miracle -- that is, an event not yet explained or demonstrated."
Which is sad, because of course the entire history and development of life on Earth _is_ a miracle, and a far more profound one than some old guy in a nightshirt waving a magic wand in 4004 BCE.
The billions of years the Earth has existed and the slow progression from inanimate molecules to people capable of arguing about it is a far more persuasive proof of the existence of a deity than any amount of bogus "answers in Genesis" nitpicks at the fossil record. I'm an atheist myself, but when I can wrap my mind around the scale of Earth's history I feel tremendous awe.
Just out of interest, what proportion of professional petroleum geologists do you think are young-earth-creationists? Hav you ever met any significant number?
Though no life creation, for there would be the other side as well.
Don't keep us in suspense.
Why, Patrick, I'm surprised that you didn't find it for yourself! ;)
Jesus saith unto him, Thomas, because thou hast seen me, thou hast believed: blessed [are] they that have not seen, and [yet] have believed. And many other signs truly did Jesus in the presence of his disciples, which are not written in this book: But these are written, that ye might believe that Jesus is the Christ, the Son of God; and that believing ye might have life through his name. (John 20:29-31)
Dont't hold your breath. Or at least blow circular smoke clouds.
I was testing you. (Yeah, right.)
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