The Earth's atmosphere consists of a gaseous envelope extending up to an altitude of approximately ______________ kilometers?
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Answer: B. 200
Explanation
Scientific definitions place the outer boundary of Earth gaseous envelope around two hundred kilometers high. Atmospheric density drops exponentially with altitude merging gradually into the vacuum of outer space. Upper thermosphere and exosphere extend up to hundreds of kilometers enclosing the planetary atmosphere. Earth atmosphere has no sharp upper boundary but thins out progressively over great distances. Gravitational attraction holds gas molecules near the planet while thermal energy pushes them outward. Karman line at one hundred kilometers is often used to define the beginning of outer space.
Low Earth orbit satellites experience slight atmospheric drag even at altitudes exceeding several hundred kilometers. Spacecraft re-entry planning requires understanding upper atmospheric density profiles and aerodynamic heating. Auroral displays occur in the upper atmosphere where solar wind particles collide with thin gases. Ten kilometers is far too low representing only the cruising altitude of commercial passenger aircraft. One thousand kilometers extends too far into the exosphere where individual gas molecules escape gravity. Two thousand kilometers encompasses outer exospheric regions where true collisional atmosphere becomes negligible.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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