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.
Luk 6:30 and Matt 5:40 Say nothing of giving more to one who steals. It says give more than you are asked of to one who asks. And if in law they take it, give more as well.
Nothing of one who steals.
On that note, my musings were derived by extrapolation from current chemical concepts. It is possible for a chemical process to have an initiation which is different from propagation. There are many examples of this and I gave initiator induced free radical polymerization as an example. Other areas of chemistry from which logical extrapolations can be drawn include chemical processes that parallel cellular structures, such as micelle and liposome encapsulation including ion mobility across short chain fatty acid membranes of these structures. This would be included in the speculative extrapolation. The challenge would be getting down and doing lab work to produce a self replicating proto-cellular structure, ideally from self assembling organic materials that are not exclusive to currently living things. If that were done, then this would demonstrate that the intial conditions were different from the self replicating conditions. In other words, initiation is different from propagation.
Not the same. What I said was basically that before a point in time, there is no evidence of life, after a point in time, there was. On this much, both science and religion agree. The transition, from no life to life is where we part ways. Science looks at it as a physical process, religion claims design. The logical fallacy is how did the designer arise? Without addressing the origins of the designer, then intelligent design (a.k.a. creationism) merely puts an extra step in the start of life.
That is not a logical fallacy, that is a question. I am not mentioning anything about ID or creationism. I am addressing your faulty logic. Your logic remains faulty, despite the validity or nonvalidity of any other argument.
Piffle.
Matt 5:39 But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
Matt 5:40 And if any man will sue thee at the law, and take away thy coat, let him have [thy] cloak also.
Matt 5:41 And whosoever shall compel thee to go a mile, go with him twain.
The general heading is "Resist not evil". But I suppose this is just a metaphor, and not an article of faith, like the six days of creation.
:-)
Turn the other cheek when wronged. Fine, how does that translate into "go out of your way to give them your property?" It just means when one disgraces you, let them.
When one sues you in the LAW, give more. That means it wasn't stolen, it was taken lawfully.
And if one compels me to go a mile, and I go extra, that means I am doing more than what is asked of me.
This is a statement of going above and beyond what is asked of you. This does not mean allow evil or give to those who would take from you illegally.
If the hemaphrodites were the precursors to sexual specialists, wouldn't the hemaphrodites still exist as the "third sex", one capable of both giving and receiving? That would seem to me to be the best way of guaranteeing the species as a whole. What would be the disadvantages of hemaphrodites coexisting with sexual specialists of the same species?
Thanks again.
I picked up a Douglas Adams compendium last weekend, so I now have the answer for all of this.
(shhh....it's 42!)
So the word "compel" doesn't imply force or the threat of force?
Agreed.
Not any more than "6 Days" implies 144 hours.
As badly as things have turned out, it is evidence for too many cooks.
Another translation of that is
"And if one of the occupation troops forces you to carry his pack one kilometre, carry it two kilometres."
This would still imply lawfulness, as it is an occupying force, not a brigand.
Can we pull this yet please?
Post #616 is not technically unlawful. Should I copy it?
The thread or the post?
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