Early Earth haze may have spurred life, says University of Colorado studyNovember 07, 2006
In a study published in the Proceedings for the National Academy of Sciences the week of Nov. 6, the research team measured organic particles produced from the kind of atmospheric gases thought to be present on early Earth. The laboratory experiment modeled conditions measured by the Huygens probe on Saturn's moon, Titan, last year during the NASA-European Space Agency's Cassini mission, according to Margaret Tolbert of CU-Boulder's Cooperative Institute for Research in Environmental Sciences, one of the study's authors.
The researchers mimicked Titan's hazy skies by exposing methane gas to an ultraviolet lamp, then added carbon dioxide gas to the mix to see if conditions that were probably present on early Earth would produce a similar organic haze. "It turns out that organic haze can form over a wide range of methane and carbon dioxide concentrations," said Tolbert. "This means that hazy conditions could have been present for many millions or even a billion years on Earth while life was evolving."
According to co-author Melissa Trainer of CU-Boulder's Laboratory for Atmospheric and Space Physics, the study was the first to measure the chemical properties of aerosols by irradiating methane and carbon dioxide with ultraviolet light. "We found that you can make a lot of organic material virtually out of thin air," said Trainer, who completed her doctoral degree in CU-Boulder's chemistry and biochemistry department at CU in May 2006 under Tolbert.
Scientists believe the atmospheric chemistry of Titan might hold valuable clues to understanding the climate on Earth when life was just forming, said Trainer. Titan is an unusual solar system moon in that it has an atmosphere - in this case one thick with organic aerosol particles that form through photochemical processes when sunlight reacts with methane gas, she said.
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."
University of Colorado at Boulder
Related Haze Current Events and Haze News Articles
L.A. story: Cleaner air, healthier kids
A 20-year study finds that millennial children in Southern California breathe easier than ones who came of age in the '90s, for a reason as clear as the air in Los Angeles today.
VISTA stares right through the Milky Way
As one of its major surveys of the southern sky, the VISTA telescope at ESO's Paranal Observatory in Chile is mapping the central regions of the Milky Way in infrared light to search for new and hidden objects.
The tell-tale signs of a galactic merger
The NASA/ESA Hubble Space Telescope has captured this striking view of spiral galaxy NGC 7714. This galaxy has drifted too close to another nearby galaxy and the dramatic interaction has twisted its spiral arms out of shape, dragged streams of material out into space, and triggered bright bursts of star formation.
To prevent new environmental disasters, China needs national conservation horizon scanning
Globe Conservation Horizon Scanning, which involves collaboration of the worldwide conservation community, focuses on identifying potential environmental problems across the planet that have not yet been noticed by society as a whole.
Unexpected turn in diabetes research
Years of diabetes research carried out on mice whose DNA had been altered with a human growth hormone gene is now ripe for reinterpretation after a new study by researchers at KU Leuven confirms that the gene had an unintended effect on the mice's insulin production, a key variable in diabetes research.
Patient's own stem cells could clear a cloudy cornea, Pitt team says
Treating the potentially blinding haze of a scar on the cornea might be as straightforward as growing stem cells from a tiny biopsy of the patient's undamaged eye and then placing them on the injury site, according to mouse model experiments conducted by researchers at the University of Pittsburgh School of Medicine.
Meteorology meets metrology: Climate research high up in the clouds
Barely has the research aircraft HALO entered the kilometre-high clouds towering above the Brazilian rainforest than the researchers find themselves in a complete haze, but they can rely on the measuring instruments that are working at full capacity.
Clean Smell Doesn't Always Mean Clean Air - Drexel Engineer Studies Indoor Aerosol Spikes Caused By Cleaning Products, Air Fresheners
Some of the same chemical reactions that occur in the atmosphere as a result of smog and ozone are actually taking place in your house while you are cleaning.
Yellow filters in eye result in higher visibility, UGA research finds
Human eyes naturally contain yellow pigment in the macula, a spot near the center of the retina responsible for high-resolution vision.
NASA Experiments Recreate Aromatic Flavors of Titan
NASA scientists have created a new recipe that captures key flavors of the brownish-orange atmosphere around Saturn's largest moon, Titan.
More Haze Current Events and Haze News Articles