Image: a Franco-Russian team calculated that the atmosphere extended up to 630,000 km beyond the Earth (almost twice as far as the Moon).
NB: The space station orbit 400 km.
A plane flies at an altitude of 10 km.
...and where does the atmosphere end?
We have the impression that space begins beyond the terrestrial atmosphere but that is not a good definition because the more the altitude increases and the less the atmosphere is dense, without really disappearing, it gradually becomes scarce.
The atmosphere begins at the Earth's surface (troposphere 0 km to 20 km altitude) and continues at extremely high altitudes (exosphere 1000 km to 50,000 km altitude).
From data collected by the Soho mission, a Franco-Russian team calculated that the atmosphere extended up to 630,000 km beyond the Earth (1.5 times farther than the Moon).
The atmosphere is diluted in space until it forms a scattered cloud extremely held in hydrogen atoms (10 to 70 atoms per cm3) called « geocrown ».
At the level of the Moon, there are only 200 atoms per cubic decimetre, in other words almost empty.
| Composition of the atmosphere | |
| Gaz | Volume or ppmv (part-per-million) |
| Dinitrogen (N2) | 78.084 % |
| Dioxygen (O2) | 20.946 % |
| Argon (Ar) | 0.934 % |
| Carbon dioxide (CO2) | 0.0415 % |
| Neon (Ne) | 18.18 ppmv |
| Helium (He) | 5.24 ppmv |
| Methane (CH4) | 1.745 ppmv |
| Krypton (Kr) | 1.14 ppmv |
| Dihydrogen (H2) | 0.55 ppmv |
Kármán Line
Image: The altitude of 120 km marks the border where the atmospheric effects become noticeable for an object when it re-enters the atmosphere.
We have the impression that space begins beyond the terrestrial atmosphere but that is not a good definition because the more the altitude increases and the less the atmosphere is dense, without really disappearing, it gradually becomes scarce.
The atmosphere begins at the Earth's surface (troposphere 0 km to 20 km altitude) and continues at extremely high altitudes (exosphere 1000 km to 50,000 km altitude).
From data collected by the Soho mission, a Franco-Russian team calculated that the atmosphere extended up to 630,000 km beyond the Earth (1.5 times farther than the Moon).
The atmosphere is diluted in space until it forms a scattered cloud extremely held in hydrogen atoms (10 to 70 atoms per cm3) called « geocrown ».
At the level of the Moon, there are only 200 atoms per cubic decimetre, in other words almost empty.