Quote:
Originally Posted by photon
True, but if the flares were 100 miles away that's still a lot less than the what, 600 or 800 miles of atmosphere (though of course it gets thin quite quickly).
Without knowing atmospheric conditions, the actual brightness of the flares, etc, it's impossible to make a judgement one way or the other.
|
The atmosphere is not very thick. I heard if you compare the earth to an apple, the skin of the apple is actually thicker than our atmosphere in relative terms.
There is no definite boundary between the atmosphere and outer space. It slowly becomes thinner and fades away into space. Three quarters of the atmosphere's mass is within 11 km of the planetary surface. In the United States, persons who travel above an altitude of 50.0 miles (80.5 km) are designated as astronauts. An altitude of 120 km (75 mi or 400,000 ft) marks the boundary where atmospheric effects become noticeable during re-entry. The Karman line, at 100 km (62 miles), is also frequently used as the boundary between atmosphere and outer space.
http://en.wikipedia.org/wiki/Earth_atmosphere