Meaning & use
the karman line
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Meaning
nounsingulartechnical
The height, usually taken as 100 kilometers above sea level, that is widely used as the boundary between Earth's atmosphere and outer space.
Grammar: Used with the: the Kármán line; it is a proper name for one boundary.
Patterns
- cross the Kármán line
- the Kármán line at somewhere
The rocket crossed the Kármán line about two minutes after launch.
Air is so thin above the Kármán line that wings can no longer lift a plane.
Passengers on the short flight briefly passed the Kármán line and felt weightless.
Common combinations
- cross the Kármán line
- The capsule crossed the Kármán line at high speed.
- reach the Kármán line
- The spacecraft reached the Kármán line in minutes.
- above the Kármán line
- Above the Kármán line, there is almost no air.
- below the Kármán line
- Weather balloons stay far below the Kármán line.
Synonyms and how they differ
- edge of space
- Edge of space is an informal phrase, while Kármán line is a specific internationally used altitude.
- space boundary
- Space boundary is a general term that could mean any chosen limit, while the Kármán line names the best-known one.
Word family
- Kármán proper noun
- Theodore von Kármán, the scientist the line is named after
- suborbital adjective
- describing a flight that reaches space but does not orbit
- atmosphere noun
- the layer of gases around the Earth
- aerospace adjective
- relating to flight in the air and in space
Commonly confused: the karman line or Armstrong limit?
the karman line vs Armstrong limit
The Armstrong limit is the height where water boils at body temperature, about 19 km up, much lower than the Kármán line.
Practice
What does the Kármán line mark?
Choose one answer.
The Kármán line, about 100 km up, is the common boundary of space. The sound barrier is a speed and not a height, and the other options are unrelated.
Make it your own
Write a sentence using “the karman line”, then check it and compare it with the examples above.