NASA: down but not out. The agency reports today that researchers operating with funding from America’s space program have proved that meteorites containing two of the organic molecules that make up DNA picked up or generated those molecules while they traveled through space, not when they came into contact with the Earth and its atmosphere.
Their findings give significant support to the theory that the origins of life on Earth are ultimately extraterrestrial.
On the meteorites, scientists not only found adenine and guanine, two of the nucleotide bases of DNA; but also hypoxanthine and xanthine, which are used in “other biological processes;” and trace amounts of purine, 2,6-diaminopurine, and 6,8-diaminopurine, “molecules related to nucleobases” that are rarely found in actual biological processes. They became confident that these substances were not present because of contamination from Earthly sources for three reasons:
Because 2,6-diaminopurine and 6,8-diaminopurine are not commonly found in biological processes it seems unlikely that they would be present because of earthly biological contamination. However, these two might be produced by the same chemical reactions that could produce nucleotides, so it’s likely that they would be around if the nucleotides arose from reactions instead of contamination.
The meteorites also contained more of these molecules than the terrestrial soil or ice in which they were found, by several orders of magnitude, making terrestrial contamination seem less likely.
Lastly, the researchers managed to prove that identical compounds could be made in the lab through non-biological reactions using only hydrogen cyanide, ammonia, and water; a plausible combination of substances to find on an asteriod.
“In fact,” according to Dr. Michael Callahan of Goddard Space Flight Center, “there seems to be a ‘goldilocks’ class of meteorite, the so-called CM2 meteorites, where conditions are just right to make more of these molecules.”
You may now consider the metaphysical consequences of all life on earth actually being alien.
(via NASA.)
