According to the study, a similar haze hanging over Earth early in its history could have supplied more than 100 million tons of organic material to the planet's surface each year. "As these particles settled out of the skies, they would have provided a global source of food for living organisms," said Trainer.
Previous efforts to understand early life on Earth have focused on extreme environments like hydrothermal vents, where energy and nutrients are plentiful, said Tolbert. The new study shows that such a high-energy food source could have been produced globally early in Earth's history, possibly expanding the habitable domain for early life, she said.
In addition to serving as a source of organic material, a haze layer over Earth could have shielded living organisms from harmful UV rays and helped to regulate Earth's early climate, according to the study. The haze may have contributed to the geologic record on Earth by depositing organic carbon into some of the planet's most ancient rocks, said Alexander Pavlov, a study co-author and former LASP researcher now at the University of Arizona. Organic carbon is believed by scientists to be of biological origin.
Other authors on the study included LASP's Owen Toon, H. Langley Dewitt and Jose Jimenez of CIRES, and Christopher McKay of NASA's Ames Research Center in Moffett Field, Calif.
"It's exciting to see that the early Earth experiments produced so much organic matter," said Carl Pilcher, director of NASA's Astrobiology Institute, headquartered at NASA Ames. "An organic haze produced this way on early Earth could have contributed to the formation and sustenance of life."
'"/>
Contact: Margaret Tolbert
margaret.tolbert@colorado.edu
303-492-3179
University of Colorado at Boulder
6-Nov-2006