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.
Organic compounds can be formed without the existence of life. Take a look at Saturn's moon, Titan. It is chocked full of organics. Organics, including amino acids, have been found all over the solar system and in interstellar space.
However, speeding up atoms corresponds to a temperature increase. One of the conditions that must be correct for life to form is the environment must have the correct temperature. If you speed up your atoms too much, life will not form because the temperature will be too high. Therefore, your idea of speeding up the process of life formation will not work.
Count the "fudge" words in any scientific paper on any subject.
If it's any good there will probably be an ample supply. (note fudge word)
That's because in science a theory can never be proven, only disproven. So, you get sentences like: "Our data seem to support the procedures and interpretation of Whosits and Smith (2005 see ref 13) and, additionally appear to challenge the conflictng interpretion of Jones and Bones (2004 see ref 3)."
At any moment a new bit of data can turn a whole mess of interpretations upside down, paradoxically making a lot of scientists extremely happy. That's because they now haave a new playground.
Good catch. I'll rephrase my question then:
Can life come from non-life and only the natural progression non-life carries out by itself? Is life self-organized?
Omne ignotum pro magnifico.
Ok, but do you realize that there is a controversy about the source of "fossil fuels?" Some are saying that it is formed by the earth itself. Others claim that the existence of organic compounds in the crude PROVE that it is from decaying life.
So, are organic compounds common without the existence of life or aren't they?
Descriptive implies a symptom. A symptom of what? What would organization and order imply? Chance or an Organizer?
The tornado argument is based upon a misunderstanding of the second law of thermodynamics. An entropy decrease in an open system is possible, since the second law only states that the total entropy of a closed system increases. Even in a closed system, it is the total entropy that increases, however. Therefore, it is possible to have an entropy decrease in one part of a closed system so long as there is a compensating increase in entropy in another part of the system. We can treat the universe as a closed system. The second law tells us that even though the universe tends toward chaos, it is not necessarily true that all parts of the universe tend toward chaos. (speaking loosely, of course, since entropy is not precisely the same thing as disorder.)
So if doing something faster won't work. And doing it the slow way is yet to yield result that we've observed... why would thinking Life came about in and of non-life be scientific?
Also, wouldn't the idea of radiation and lightning causing life in "soup" mean that heat incourages life? Can't things live in several hundred degress Celcius?
Sure, it's much better to state the truth and never admit that you have any possibility of being wrong. That will lead you to the truth in a much more efficient way since you never have to consider new evidence or modify your belief. This whole idea of provisionally accepting an idea, testing it against observations, and then modifying it if necessary is no way to get to the truth. It's much better to be completely certain about every idea you come up with, even if the idea is wrong. Then at least it isn't speculation. </sarcasm off>
And which religious leader has ever proven that science has gotten it wrong? Oh yeah, that's right, none of the mistakes made by scientists were ever corrected by a religious leader; they were all corrected by other scientists. That's the way science works. It may make mistakes, but it will eventually correct these mistakes. In order to show that science is mistaken and correct a mistake, you have to do more than simply say, "I don't believe this," or "I can't see how this could be true." You must actually go out and do some science yourself. Provide evidence, observations and experiments. Come up with your own theory which you believe explains things better than the current one. Do some tests that could actually show that your theory is false. If it passes these tests, and actually does explain things better than the currently accepted theory, then it will replace the current theory.
the·o·ry:
"from Gk. theoria "contemplation, speculation, a looking at, things looked at," from theorein "to consider, speculate, look at," from theoros "spectator," from thea "a view" + horan "to see." Sense of "principles or methods of a science or art (rather than its practice)" is first recorded 1613. That of "an explanation based on observation and reasoning" is from 1638."
Hopwver, you need to be clear in what you mean by organic componds being "common" with or without the existence of life. On earth, organic materials have been effectively taken up by the biosphere so it is safe to say organic material in our immediate environment is biotic in nature. That does not mean all organic material in our area is biotic. Organic material in space is abiotic. The materials in comets, some asteroids and in inorganic dust is more primordial organic material. It represents organic material that would have been present in the early solar system and on the early earth before life. Life on earth has basically been recycling the same organic material, that had abiotic origins, for millions of years.
Well then, you will have no science at all. Science doesn't deal in certainty, merely in preponderance of evidence. Currently there's not much evidence out there regarding the origin of life, so this field is admittedly pretty speculative. It is relatively more speculative than many other areas of science, but no other area of science is certain. Any of the currently accepted ideas in science could be demonstrated to be incorrect at any time. Of course, it takes more than someone saying that they don't believe it to do this.
Actually, (and I'm not a biologist or biochemist so I may not be up to date on this) I think that scientists are still working on just the first step in such a process, namely the production of organic compounds from materials likely to be available on the early earth. I don't think that there's been a whole lot of serious research on the other intermediate steps that would be necessary to go from organic compounds to living cells. This is an obvious starting point for abiogenesis research, since if it could be shown that the formation of the necessary organic compounds could not have happened in the first place then there's no reason to even consider the other steps necessary to produce life. Of course, like I said, there may very well be research into the other intermediate steps that I am unfamiliar with.
That holds the same way "Chaos" now means "random"
It's roots were retranslated to form our modern use of the word.
BTW, Chaos means "gaping hole"
God formed man from "the dust of the earth". When He was forming man, was that "dust" originally single cells?
No. Heat, radiation, and lightning are all forms of energy. However, their effect in chemistry, their ability to do chemical work, is dramatically different. In a small temperature range, life as we know it, can thrive. Variations in heat, are tolerabel to differeing degrees to different organisms. However, the formation of the materials that comprise living things from an abiotic source can be quite energetic. Once formed, they can be incorporated into a living thing (example as food). Howver, the same energetic phenomena can destroy these same chemicals, hence killing the organism which is comprised of them. There is also the frequency, duration and spatial distribution of the energies involved. You can have one area where the chemicals are formed and another area where they are safe from disruption. Lighting is specific in time and location, for example.
Absolutely! We have observed organic compounds in interstellar space, for example. (Or if you prefer, we have seen light spectra that indicate the presence of organic compounds in space.) Organic compounds are nothing more than compounds of the element carbon. Carbon is formed in nuclear reactions in stellar cores. Life is not required for the formation of carbon. Carbon can then react with hydrogen, oxygen and any of a number of other elements to form organic compounds, once is has been dispersed to cooler environments. That was the whole point of the experiment by Wohler in the 19th century. If you are unfamiliar with it, that experiment involved the synthesis of urea, an organic compound, from inorganic starting materials and conclusively proved that life was not necessary for the production of organic compounds.
There are a lot of interesting chemistry and biochemistry issues involved in this. My favorite, and one I'm surprised no one has mentioned yet, is the chirality of the amino acids, and other complicated organics, in living things.
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