Warming Earth makes satellites move faster

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When you think about CO₂ emissions from the use of fossil fuels, you probably think about climate change. Temperature. Maybe precipitation patterns. Storms. But do you think about managing the orbital mechanics of satellites?

As humans, we really only experience the lower atmosphere—the troposphere and stratosphere that extend about 30 miles from the surface. That’s where nearly all of the gas in the atmosphere resides, and that’s where weather happens. Even Felix Baumgartner, the daredevil skydiver, "only" jumped from the stratosphere. But technically, the atmosphere extends a whole lot higher than that. It’s another 150 miles or so before we truly reach interplanetary space. A number of satellites, as well as the International Space Station, are actually whizzing around in a layer of the atmosphere called the thermosphere.

Down in the troposphere, CO₂ is an important greenhouse gas. Add more CO_2, and you trap more outgoing heat, warming the lower atmosphere. But up in the thermosphere, things are much different. Gas molecules are incredibly sparse—and increasingly so as you head outward from the Earth. Here, CO₂ is actually a key coolant, as it absorbs energy from collisions with oxygen molecules, and then emits that energy as infrared radiation, sending much of it out into space.

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