Earth's early haze
- From: TomHendricks474@xxxxxx
- Date: Sat, 11 Nov 2006 02:08:29 -0500 (EST)
Posted: November 7, 2006
From Spaceflightnow.comNote UV component.
U. Of Colorado - Boulder news release
Hazy skies on early Earth could have provided a substantial source of organic
material useful for emerging life on the planet, according to a new study led
by the University of Colorado at Boulder.
"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. ...
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. "
It goes on to say this may have protected earth from harmful UV.
Again I don't see UV as harmful overall - I think it is a necessary
component of life processes.
.
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