As a result of the solar maximum, Earth's atmosphere is "puffed up" like a marshmallow over a campfire leading to extra drag on Earth-orbiting satellites.

If you hold a marshmallow close to a roaring camp fire it puffs up. A well-roasted marshmallow can grow to nearly twice its normal size, doubling its allure to a voracious sweet tooth.

Something similar happens to Earth's atmosphere every 11 years when the sunspot cycle nears maximum. As solar activity increases, extreme ultraviolet radiation (EUV) heats our planet's gaseous envelope, causing it to swell and reach farther into space than normal. While puffed-up marshmallows can lead to tooth decay, our puffed-up atmosphere vexes satellite operators with a different kind of problem -- orbit decay.

Above: The space shuttle orbits in the thermosphere, a tenuous layer of our atmosphere that gets hotter and expands during solar maximum. The puffed-up thermosphere increases drag on Low Earth Orbit (LEO) satellites.

"There are layers of our atmosphere that extend hundreds of kilometers above Earth's surface," explains Dr. David Hathaway, a solar physicist at the Marshall Space Flight Center. "The space shuttle and the ISS both orbit within the thermosphere. The thermosphere is about a million times less dense than the atmosphere at sea level, but that's enough to affect the orbits of these satellites."

Full Story: http://science.nasa.gov/headlines/y2000/ast30may_1m.htm?list

Mitch Battros
Producer - Earth Changes TV
http://www.earthchangesTV.com