Food for Earth’s earliest inhabitants may have fallen from thin air, according to Colorado researchers.
A team of scientists from the University of Colorado and NASA mixed methane and carbon dioxide – two chemicals believed to be present in Earth’s atmosphere a few billion years ago – and spiced the brew with a whiff of radiation from an ultraviolet light bulb.
The product: a haze of energy-rich organic chemicals that could have rained down on primeval organisms growing on the Earth’s surface.
Previously, scientists suspected Earth’s early life was concentrated in extreme environments, such as hydrothermal vents, because only there would there have been plenty of energy and nutrition.
“If our mechanism is correct, we have a global source of food that’s slowly settling down everywhere,” said Margaret Tolbert, a scientist with CU’s Cooperative Institute for Research in Atmospheric Sciences.
Tolbert and her colleagues from CU and the NASA Ames Research Center in Moffett Field, Calif., published their findings Monday in the Proceedings of the National Academy of Sciences.
A similar sort of organic smog occurs on Saturn’s moon Titan, recently visited by the Cassini spacecraft and Huygens probe.
“But the chemistry is different,” said Melissa Trainer, lead author of the new paper who completed her Ph.D. in Tolbert’s laboratory in May.
“It’s a lot less obvious that the chemistry in Titan’s atmosphere produces chemicals in the haze are biologically useful,” Trainer said.
Carl Pilcher, who directs NASA’s Astrobiology Institute at NASA Ames, called the new experiment “exciting” because it produced so much organic matter.
Staff writer Katy Human can be reached at 303-954-1910 or khuman@denverpost.com.
