Which statement best describes the thermosphere?

Which statement best describes the thermosphere?

• A. Very thin air, very high temperatures; includes auroras; where the ISS and satellites orbit
• B. Dense air, low temperatures; home to weather systems
• C. Medium air density with moderate temperatures; home to trade winds
• D. Water cycle occurs here; forms clouds

Answer: (A)

The thermosphere is where the air is extremely thin, yet it gets very hot due to absorbing a lot of solar radiation. This is also the layer where auroras occur and where human-made objects in low Earth orbit, like the International Space Station and many satellites, travel. So the statement that combines very thin air, very high temperatures, auroras, and orbiting spacecraft describes this layer best. In contrast, weather systems form in the much denser lower atmosphere (the troposphere), the trade winds and similar mid-atmosphere features aren’t characteristics of the thermosphere, and the water cycle forming clouds happens in the troposphere as well.

The thermosphere is where the air is extremely thin, yet it gets very hot due to absorbing a lot of solar radiation. This is also the layer where auroras occur and where human-made objects in low Earth orbit, like the International Space Station and many satellites, travel. So the statement that combines very thin air, very high temperatures, auroras, and orbiting spacecraft describes this layer best. In contrast, weather systems form in the much denser lower atmosphere (the troposphere), the trade winds and similar mid-atmosphere features aren’t characteristics of the thermosphere, and the water cycle forming clouds happens in the troposphere as well.