quarta-feira, 7 de julho de 2010

As alterações climáticas criam mais lixo orbital


There are lots of consequences of a warming world, a lot of them easy to infer and understand (i.e. melting glaciers), but some consequences have come to light that weren't so expected, like a reduction in crop nutritional value and, now, an increase in space junk orbiting the earth.

Scientists at the University of Southampton have studied the orbits of 30 satellites over the past 40 years and discovered that they're taking longer to drop out of orbit and burn up.  The scientists think that increased CO2 in the upper atmosphere is causing it to cool and become less dense, slowing the braking effect and allowing satellites and spent rockets to circle for longer.
The researchers measured a five percent reduction in density every decade at an altitude or 300 kilometers, leading to an increase in orbit time of up to 25 percent.
More space junk does pose a danger for spacecraft launches and will require more debris removal by space agencies, but with the scaling back of our nation's space program and bigger problems down here on the ground, it's not likely to become a major issue.
via New Scientist

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