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DNA in meteors suggests we're not alone
By Andrew Lam |
August 20, 2011, Saturday
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FIFTEEN years ago when scientists postulated that a Martian meteorite named Allan Hills might contain evidence of microscopic fossils of bacteria, the news was received with a mixture of astonishment and skepticism.
Now, NASA researchers supported that theory by finding evidence that suggests nucleobases - the building blocks of genetic material - do exist in certain meteorites.
"People have been discovering components of DNA in meteorites since the 1960s, but researchers were unsure whether they were really created in space or if instead they came from contamination by terrestrial life," observed Dr Michael Callahan, lead author of a study just published in the Proceedings of the National Academy of Science, reported the Atlantic. "For the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually were created in space."
But the researchers went further. These building blocks, they noted in their NASA-funded study," may have served as a molecular kit providing essential ingredients for the origin of life on earth and possibly elsewhere." The discovery - and the idea that our planet is part of an infinitely vast interstellar ecosystem - is astonishing, but alas, it came at a time of great social turmoil here on earth. It was buried on the proverbial page 3.
Yet it may very well be that a few decades from now, when we look back at 2011, the pivotal moment in human history is not mass starvation in the Sub-Saharan regions due to global warming, nor that the United States as a global empire staggered toward its collapse, nor that Europe went up in flames due to social inequity, but that, in the long view of man's arduous history, the discovery that DNA came from space gave him a new and profound insight into his relationship with, and his appreciation of, the cosmos.
After all, none of the major religions came close to the idea of panspermia (a Greek word meaning "all seeding"), or the interstellar exchange of DNA, a hypothesis that was championed by Francis Crick, who discovered the structure of the DNA molecule with two other scientists last century. If scientists laughed behind the Nobel laureate's back when he first suggested it, no one is laughing now.
Our ideas about the universe have shifted in the last couple of decades thanks to new discoveries. Once thought to be found on earth only, we now have found for instance that water, that basic element for biological forms, exists everywhere in cold, dark space.
Cosmic snowballs, we find, hit earth's atmosphere at frequent intervals. And comets, for instance, are full of "dirty ice" and organic molecules. Even our atmosphere-less moon is found to have water in the form of ice in its craters. Mars, too, has water underneath its barren soil in the form of ice.
And more astounding, as if in a cartoon fantasy, we recently discovered that Enceladus, one of Saturn's moons, actually rains water down onto the planet's upper atmosphere, forming rings of water vapor. Scientists speculate that there's an ocean underneath its ice, yet to be discovered.
Just as astonishing, the Kepler, NASA's space-based telescope launched two years ago, has found some serious possibilities for potential life out there. So far it found 1,235 planets orbiting nearby stars. More importantly, it has found 54 planets in habitable zones, with protective atmospheres and liquid water - conditions that may support life. "It's very likely that life is common in our galaxy," speculated the chief scientist of the Kepler mission, William Borucki.
Not so long ago, until Copernicus came along, we assumed our world was the universe's center - and, for that matter, flat - and that the sun orbited earth. Last century, we held on to the notion that our solar system was unique. Scientists just a generation ago assumed, too, that conditions on earth - a protective atmosphere, ample water and volcanic activity - made it the only planet that could possibly support life.
That sense of self-importance has given way to a more humble assessment of our place in space.
We are an integral part of the cosmos, and we are, if the hypothesis of panspermia pans out, all aliens in one way or another.
What myth of creation, one wonders, should arise now when alien rocks carrying primordial soup might have given rise to all living things, and that earth is but one of countless gardens waiting to be "seeded" in the vast and mysterious universe?
Andrew Lam, editor of New America Media, San Francisco, is author of "East Eats West: Writing in Two Hemispheres". Shanghai Daily condensed his article.
Now, NASA researchers supported that theory by finding evidence that suggests nucleobases - the building blocks of genetic material - do exist in certain meteorites.
"People have been discovering components of DNA in meteorites since the 1960s, but researchers were unsure whether they were really created in space or if instead they came from contamination by terrestrial life," observed Dr Michael Callahan, lead author of a study just published in the Proceedings of the National Academy of Science, reported the Atlantic. "For the first time, we have three lines of evidence that together give us confidence these DNA building blocks actually were created in space."
But the researchers went further. These building blocks, they noted in their NASA-funded study," may have served as a molecular kit providing essential ingredients for the origin of life on earth and possibly elsewhere." The discovery - and the idea that our planet is part of an infinitely vast interstellar ecosystem - is astonishing, but alas, it came at a time of great social turmoil here on earth. It was buried on the proverbial page 3.
Yet it may very well be that a few decades from now, when we look back at 2011, the pivotal moment in human history is not mass starvation in the Sub-Saharan regions due to global warming, nor that the United States as a global empire staggered toward its collapse, nor that Europe went up in flames due to social inequity, but that, in the long view of man's arduous history, the discovery that DNA came from space gave him a new and profound insight into his relationship with, and his appreciation of, the cosmos.
After all, none of the major religions came close to the idea of panspermia (a Greek word meaning "all seeding"), or the interstellar exchange of DNA, a hypothesis that was championed by Francis Crick, who discovered the structure of the DNA molecule with two other scientists last century. If scientists laughed behind the Nobel laureate's back when he first suggested it, no one is laughing now.
Our ideas about the universe have shifted in the last couple of decades thanks to new discoveries. Once thought to be found on earth only, we now have found for instance that water, that basic element for biological forms, exists everywhere in cold, dark space.
Cosmic snowballs, we find, hit earth's atmosphere at frequent intervals. And comets, for instance, are full of "dirty ice" and organic molecules. Even our atmosphere-less moon is found to have water in the form of ice in its craters. Mars, too, has water underneath its barren soil in the form of ice.
And more astounding, as if in a cartoon fantasy, we recently discovered that Enceladus, one of Saturn's moons, actually rains water down onto the planet's upper atmosphere, forming rings of water vapor. Scientists speculate that there's an ocean underneath its ice, yet to be discovered.
Just as astonishing, the Kepler, NASA's space-based telescope launched two years ago, has found some serious possibilities for potential life out there. So far it found 1,235 planets orbiting nearby stars. More importantly, it has found 54 planets in habitable zones, with protective atmospheres and liquid water - conditions that may support life. "It's very likely that life is common in our galaxy," speculated the chief scientist of the Kepler mission, William Borucki.
Not so long ago, until Copernicus came along, we assumed our world was the universe's center - and, for that matter, flat - and that the sun orbited earth. Last century, we held on to the notion that our solar system was unique. Scientists just a generation ago assumed, too, that conditions on earth - a protective atmosphere, ample water and volcanic activity - made it the only planet that could possibly support life.
That sense of self-importance has given way to a more humble assessment of our place in space.
We are an integral part of the cosmos, and we are, if the hypothesis of panspermia pans out, all aliens in one way or another.
What myth of creation, one wonders, should arise now when alien rocks carrying primordial soup might have given rise to all living things, and that earth is but one of countless gardens waiting to be "seeded" in the vast and mysterious universe?
Andrew Lam, editor of New America Media, San Francisco, is author of "East Eats West: Writing in Two Hemispheres". Shanghai Daily condensed his article.
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