.. Carman line
The Kármán Line is the dividing line between the Earth's atmosphere and the beginning of outer space, and is located 100 kilometers from the Earth's surface.
This line was named after the Hungarian-American physicist and engineer Theodor von Kármán (1881-1963), who worked in the field of aeronautics and astronautics. Kármán was the first to calculate that around that altitude (100 km), the atmosphere becomes very thin for the purposes of aeronautics. (Because any vehicle at this altitude would have to fly at a speed faster than orbital speed in order to extract sufficient air lift from the atmosphere to enable it to support itself, neglecting centrifugal force.)
Although the distance of 100 kilometers is very close to the Earth, it is still within the Earth's gravity and the extended atmosphere, but this relatively close location has been accepted as the dividing line between Earth and space, but why?
The definition of the Kármán line is based on physical reality, as it indicates the altitude at which conventional aircraft can no longer fly effectively, due to a change in the physical laws that govern the vehicle’s ability to fly.
Although the atmosphere extends above the Karman line, the air becomes very thin in those high places. Therefore, anything traveling above the Kármán Line needs a propulsion system that does not depend on the lift generated by the Earth's atmosphere.
The engineer, physicist and astronaut Theodor von Kármán was the one who proposed setting the Kármán line at an altitude of 100 km (Getty)
Determine the Karman line
Pinpointing exactly where space begins can be somewhat difficult, because Earth's atmosphere does not end suddenly, but rather becomes thinner at higher altitudes, meaning there is no defined upper limit.
According to the Astronomy website, the engineer, physicist and astronaut Theodor von Karmann had suggested that the most logical edge of space would be near the place where orbital forces exceed aerodynamic forces, deciding that 100 kilometers was a good limit.
The Kármán line got its name from this Hungarian scientist, born in 1881, because he was among the first to calculate the altitude above which aerodynamic lift could no longer keep the plane aloft. After working in the years following World War I on early designs for helicopters.
The atmosphere does not end suddenly at any particular altitude, but becomes progressively thinner with altitude. In addition, the definition of the "boundary of space" can vary greatly depending on the definition of the different layers that make up the space around the Earth (and depending on whether those layers are considered part of the atmosphere Actual atmosphere: If one were to consider the thermosphere and exosphere together as part of the atmosphere rather than space, one could extend the boundary with space to at least 10,000 km above sea level.
Source: websites