Over 4 billion years ago the young and barren Earth was being buffeted by meteor strikes, and that violent bombardment could have created the first amino acids that then gave rise to the origin of life on the planet, a new study suggests. The hellish temperatures and pressures generated when an extraterrestrial object strikes Earth at speeds of several kilometers per second are enough to shatter and vaporize rock…. Yet part of such an immense burst of energy can trigger chemical reactions that generate complex organic substances from basic inorganic ingredients, says Takeshi Kakegawa [Science News].
Previously, researchers have suggested that organic molecules may have been created elsewhere in the universe and were brought to Earth by meteors. But the new study, in which researchers simulated the impact of meteorites in the primordial ocean, argues that the organic molecules could have been synthesized from the inorganic molecules already present on the planet when the meteorites crashed into the ocean. Other researchers have suggested similar processes for the creation of organic molecules on Earth, including lightning strikes or chemical reactions surrounding hot, volcanic vents in the deep sea.
In the study, published in Nature Geoscience [subscription required], the researchers fired meteorite-like balls of iron and carbon into a mixture of water and ammonia, meant to resemble the oceans billions of years ago. In the experiment, the researchers found that the iron and carbon were heated by the impact and reacted with hydrogen and nitrogen to form biomolecules, including fatty acids, amines and the amino acid glycine [Cosmos Online]. Amines are the building blocks for more complex amino acids, and fatty acids are found in cell membranes.
While experts describe the results as plausible, the research hasn’t won over everyone. “It’s neat to show that you could harness the energy of impacts to create organic bonds,” says Jennifer Blank, an astrobiologist at the SETI Institute in Mountain View, Calif. But she fears that theories of life’s origin may never move beyond the hypothetical. “As someone in the general field, one of the frustrations, of course, is that we’re never going to know the answer,” she says. “But as another mechanism for contributing to the inventory of organic compounds, this is cool” [Scientific American].
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Image: NASA
December 8th, 2008 at 11:56 am
The thing that I actually like about all these different theories, is that there are so many of them. While we may not know for sure how it happened on earth, it seems to me that there are a myriad of ways for life to get started. It’s really rather exciting!
And before anyone treats the word theory as if it were a guess, please read this: http://wilstar.com/theories.htm Laypeople can make scientific talks so frustrating…
December 9th, 2008 at 12:54 am
Recent scientific knowledge gained in the last couple of centuries has increased our knowledge of the universe by .10. So we still have to figure out about the other 90%.
December 15th, 2008 at 9:45 am
Life looks so easy to create from Universal point of view, it could have begun in all the ways we have until now -meteorite, volcano or a lightening. The best thing about it is that you can have it started all over the Universe, because flying rocks and volcanos are pretty frequent events. Even oceans aren’t so rare if we believe of our Solar system.
January 6th, 2009 at 11:22 pm
Wow.
This is cool. Also, scientists are getting really close to building simple life forms in a laboratory. That will be huge, but if scientists are able to create simple life forms by shooting meteors into water, to me that would be even bigger. Making life in a lab will be cool and benefit us in health ways and such, but proving that life can be created rather simply through random events and inorganic materials… that could mean something huge about our existence and the rest of the universe.
It would mean the possibility that life forms are all over the universe AND have been and will be for a long time. To some this is scary, to me this is hopeful. It would connect our own existence to another cycle of life and death (the life and death of planets of life).