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.
Actually, itd have to be in a vaccum. ONLY the compounds and the energy involved. No other agents.
Remember Gak?
That stuff smelled funny and moved weird, but I could never get enough of it.
I dried all mine out, and all I had to do was re-wet it.
It was great!
"WRONG! The scientist are playing the role of the creator in the lab. The only way to prove life formed itself is to put all the compounds on a table, shut the door, and watch it grow."
You do realize it is impossible to create a setting that was identical to the earths early environment in the lab. It is also impossible to mimic billions of years of time. Why do you think scientists will ever be able to do this?
Uh uh. If one science is suppose to be legit, why not all the others? According to Quantum scientists, the universe had to be created by a thought, a word, or some kind of conciseness.
The Bible says "In the beginning was the WORD. The word was with God, and the word was God."
True, it can never be observed, it can never be replicated, it can never be repeated. So, how is it science?
Evolution is NOT abio-genesis.
I proudly tell people that I feel that the mechanism called evolution could have been used by God to make us into what we are today.
The reason I qualify it "mechanism" and not just "theory" is that in the theory, there is no guiding hand. This is where evos jump to the idea of abiogenesis. The changes (though not entirely sound IMO) could very well be. They would just happen to be from the will of a Higher Being.
"Luckily for good 'ol stubborn man kind, quantum psychics (GASP! Why, that's "science" too!) is finally catching up with religion, and it's about time."
Quantum physics resembles religion only in that they are both so contrary to what our senses tell us as to be hard to believe. Unlike religion, quantum physics is testable.
"They do not question their premise (life arose spontaneously from dead matter)"
Of course life arose from organic compounds (what you call dead matter). Where else would it come from? Did it appear magically out of thin air? Are new species appearing instantly from non-existence to existence, or are they the result of sexual and non-sexual reproduction?
If you believe that species were suddenly put on earth by god you are of course rejecting not only evolution but the laws of physics as well.
thanks for the ping.
I've got a question for the up to 40% hydrogen crowd. Where did the 80% nitrogen atmosphere come from? Remember this is a rocky planet between two other rocky planets. The hydrogen planets are big, gassy, and cold.
which quantum scientists? I'm looking at my Quantum books and they don't mention this part of the theory. Is it related to the wave function of the ground state or first electronic state of dopamine? Perhaps coupled to it's vibrational and rotational modes? But that energy distribution would also have a temperature dependence. Or perhaps I chose the wrong neurochemical or I need to do my normal coordinate analysis and make sure I choose the correct point group.
"True, it can never be observed, it can never be replicated, it can never be repeated. So, how is it science?"
It can be observed if we find a planet or moon with conditions similar to what early Earth might have been like. We just don't have the ability to do that research at this time.
Np, I figured it was a good general interest for someone like yourself.
Because they're just taking an anti-God guess? If they can't reproduce it, how do they know? Do they just pull their ideas out of a hat? Everyone puts in a theory, and they choose the first one that's pulled out if it sounds like it would fly?
You aren't making yourself clear here.
If life only comes from life, how/why would one assume life came from non-life?
"If Earth's atmosphere was hydrogen-rich as we have shown, organic compounds could easily have been produced."
Mmmm hmmmm. Exactly how gullible does this guy think we are?
Some people believe that it was in the form of ammonia, NH3. Also, the atmosphere of Venus contains almost the exact same quantity of nitrogen as Earth (on a mass basis). Only Venus has a heck of a lot of CO2 so the proportion of nitrogen is a lot lower. Also, only the upper atmospheres of the gas giants are cool. Jupiter is quite hot. It emits more infrared (heat energy) into space than it receives from the sun.
The God of the Bible always was. He has no "creation story"
The Norse gods have one. The Romans, the Egyptians. The Chinese don't... but they also hold that their one God is a supreme idea that has always been, and they chose not to focus on Him.
"If they can't reproduce it, how do they know?"
If you are really that curious you can go to a university and spend many years studying geology, or even better go read up on these scientific journals with the original articles and see how they came to their conclusions. If you disagree with how they obtained their conclusions you can write a scientific paper elucidating how they screwed up and why their hypothesis is incorrect. That is how science works. Just because you don't know why they believe what they believe doesn't make it necessarily wrong.
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