Early Earth Haze Likely Provided Ultraviolet Shield for Planet (Titan)

Lots of eyes on Titan this year!

A new study shows a thick organic haze that enshrouded early Earth several billion years ago may have been similar to the haze now hovering above Saturn's largest moon, Titan, and would have protected primordial life on the planet from the damaging effects of ultraviolet radiation.

The University of Colorado at Boulder scientists believe the haze was made up primarily of methane and nitrogen chemical byproducts created by reactions with light, said CU-Boulder doctoral student Eric Wolf, lead study author. Not only would the haze have shielded early Earth from UV light, it would have allowed gases like ammonia to build up, causing greenhouse warming and perhaps helped to prevent the planet from freezing over.

The researchers determined the haze of hydrocarbon aerosols was probably made up of fluffy, microscopic particles shaped somewhat like cottonwood tree seeds that would have blocked UV but allowed visible light through to Earth's surface, Wolf said.

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Lab simulations helped researchers conclude that the Earth haze likely was made up of irregular "chains" of aggregate particles with greater geometrical sizes than spheres, similar to the shape of aerosols believed to populate Titan's thick atmosphere. Wolf said the aggregate aerosol particulates are believed to be fragmented geometric shapes known as fractals that can be split into parts.

"Methane is the key to make this climate model run, so one of our goals now is to pin down where and how it originated," said Toon. If Earth's earliest organisms didn't produce the methane, it may have been generated by the release of gasses during volcanic eruptions either before or after life first arose -- a hypothesis that will requires further study, he said.

www.sciencedaily.com...

reply to post by sandri_90


Nice find!

To be honest, I'm getting to the point where my attitude is: "So there's almost certainly life on other planets. So what?"

Not to detract from the gravity of the situation, I just can't believe it's taking N.A.S.A. so long to tell us what we already have a pretty good idea of. Why are all these finds only coming to light now?

(edit - planets and moons that is!)

[edit on 6-6-2010 by OZtracized]

Originally posted by OZtracized
...Not to detract from the gravity of the situation, I just can't believe it's taking N.A.S.A. so long to tell us what we already have a pretty good idea of. Why are all these finds only coming to light now?

Well, NASA scientists have a pretty good idea that life exists elsewhere, also -- but having a "pretty good idea" does not constitute real evidence.

Most NASA scientists I hear speak talk freely about their belief in life elsewhere (usually based on the shear size of the universe, and what they know about extremophile life on Earth) -- but until they actually find that life elsewhere, it is only a belief.