Lesson plan
Thermopause
The thermopause is the atmospheric boundary of Earth's energy system, located at the top of the thermosphere. The temperature of the thermopause could range from nearly absolute zero to . Below this, the atmosphere is defined to be active on the insolation received, due to the increased presence of heavier gases such as monatomic oxygen. The solar constant is thus expressed at the thermopause. Beyond (above) this, the exosphere describes the thinnest remainder of atmospheric particles with large mean free path, mostly hydrogen and helium. As a lower boundary for the exosphere this boundary is also called the exobase. The exact altitude varies by the energy inputs of location, time of day, solar flux, season, etc. and can be between high at a given place and time because of these. A portion of the magnetosphere dips below this layer as well. Although these are all named layers of the atmosphere, the pressure is so negligible that the chiefly-used definitions of outer space are actually below this altitude. Orbiting satellites do not experience significant atmospheric heating, but their orbits do decay over time, depending on orbit altitude. Space missions such as the ISS, Space Shuttle, and Soyuz operate under this boundary.
Article summary
The thermopause is the atmospheric boundary of Earth's energy system, located at the top of the thermosphere. The temperature of the thermopause could range from nearly absolute zero to . Below this, the atmosphere is defined to be active on the insolation received, due to the increased presence of heavier gases such as monatomic oxygen. The solar constant is thus expressed at the thermopause. Beyond (above) this, the exosphere describes the thinnest remainder of atmospheric particles with large mean free path, mostly hydrogen and helium. As a lower boundary for the exosphere this boundary is also called the exobase. The exact altitude varies by the energy inputs of location, time of day, solar flux, season, etc. and can be between high at a given place and time because of these. A portion of the magnetosphere dips below this layer as well. Although these are all named layers of the atmosphere, the pressure is so negligible that the chiefly-used definitions of outer space are actually below this altitude. Orbiting satellites do not experience significant atmospheric heating, but their orbits do decay over time, depending on orbit altitude. Space missions such as the ISS, Space Shuttle, and Soyuz operate under this boundary.
Key claims
No claims recorded.
Discussion questions
- Summarise the article in your own words. Which single claim would you verify first, and why?
- Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
- If two sources disagreed about one of these facts, what would you need in order to trust one over the other?
Bibliography
No sources recorded.
Key claims and bibliography are generated from the same tracked claims and sources as the article page.