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.
"Evolution is NOT abio-genesis"
But evolution does depend on abio-genesis as its source of building blocks.
A stone wall can't be built without the stones.
Explain to me how the creature they're calling "early man" had a backbone that connected to the skull like that of a monkey, yet in one gigantic "missing link", the back bone of a man connects to the skull like that of a bear with completely different DNA??
I think "cave man" was just another animal. Maybe it's just big foot.
Ah, but walls can be built of things other than stones.
Then just say "the universe always was" and you get the same result.
I should emphasize "could" more often.
Did you miss the part where I said the idea evolution was weak?
Or a builder!
"If life only comes from life, how/why would one assume life came from non-life?"
I never said life only comes from life. I also stated life may have started with organic compounds (organic compounds are not living per se, it just a chemistry term which refers to any compound containing a carbon based structure)that would not be classified as life. Amino acids for example are not alive, but are necessary for all known life to exist.
Not really. What if Time is a qaulity God gave the Universe.
Truth always was. The Universe came about from Truth. God is Truth.
well then we agree on part of it then.....I have no Idea what set the wheels into motion...I just dont know....
Funny, such experiments still go on. And with the rise of nanotechnology and molecular machining, are likely to be successful. Why ? To understand what life is, you HAVE to be able to model it, and re-create the processes. That's standard scientific and engineering practice: you take it apart, see how it works, and re-build it, or build it from scratch. We're only now approaching the technological level where artificially-created life becomes a possibility. . . .
Your arguement suggested the opposite. As I said, you didn't make yourself clear.
The only difference between the laws of theology and the laws of quantum are the choices of words. The power of prayer can be tested, just like the thought process can move a molecule. Religion has heavens, psychics has dimensions. Religion is without time, psychics has time warps. The relationship goes on and on.
Quantum psychics goes as far as saying something started it all, a conciseness, but has fallen short of giving the entity a name. They have yet to put "it" into a mathematical formula.
Originally earth had a reducing atmosphere. We're still together on that, aren't we?
I believe the premise here is hydrogen not ammonia. The reason for more carbon dioxide in the venusian atmosphere might be that life does not exist on the planet and carbon is not tied up in living or previously living things. As for Jupiter, it is cold. Mean surface temperature: -150°C
Time is a dimension peculiar to the universe, but the singularity that initiated the universe was there beyond time and whatever caused it to explode was there as well. You can call it God or whatever else makes you happy but whatever it is that you called it nonetheless came to be ex nihilo so far as we can reason.
Thus far, science can only take us back as far as the singularity, sort of, but science has never claimed that nothing preceded it. Science cannot do that, at least not with our current limitations.
Thanks for the ping!
PS. That's why it's a misnomer to call the Big Bang the "origin" of the universe.
It's simple after that then.
The part you don't fully grasp. The ideas you know are there, yet don't comprehend. The Truth just outside of reach (and thereore, scientific proof) is God.
God set the wheels into motion. Whatever you want to call God, He, She, Block of Cheese, God is God. God is the "Universal" discovered by Platonic philosophy. The Perfect Form of perfect forms.
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