Question

The earth's atmosphere extends upwards for about how many kilometret

Answer 1

The outermost layer of the earth's atmosphere is the exosphere, which contains most of earth's orbiting satellites. It extends from the 'exobase' (which is located at an altitude of about 700 km above sea level) to about 10,000 km above sea level, after which it gets so thin that it is no longer considered to be part of the earth's atmosphere.

So, to answer your question, the earth's atmosphere extends upwards for about 10,000 kilometers above sea level.

Hope it helps!