DiscussWorldIssues - Socio-Economic Religion and Political Uncensored Debate - View Single Post

**IdomeoreTew** · 06-30-2012, 12:00 PM

Given the sky is just a blue illusion of a covering, how are you defining earths atmosphere ? - I say they are still in earths "atmosphere" if you count the Van Allen radiation belts? Are you saying they went past these ??

What do you mean by "Blue illusion", its actually blue.

The van Allen radiation belt has nothing to do with the atmosphere. In physics, the atmosphere is defined in two ways:
1) The Kármán Line which 100 km from sea level
2) The place where fiction starts to become measurable when a spacecraft/rocket is descending down to Earth (I dont know the exact height of this)

I was using the second definition because for the spacecraft to orbit the Earth there needs to be very little friction, otherwise it would just go through orbital decay and slowly descend back to earth and the astronauts would not get any work done.so they must have been above the Earths atmosphere.

In reality though, there's no concrete boundary-line where the atmosphere ends and outer space starts. The atmosphere doesn't even really end, its just progressively gets thinner and thinner. Even the Kármán Line is an arbitrary definition. The second definition makes more sense to me though because its the one used by aerospace engineers and applies more to this situation.

06-30-2012, 12:00 PM	#9
IdomeoreTew Join Date Oct 2005 Posts 562 Senior Member	Given the sky is just a blue illusion of a covering, how are you defining earths atmosphere ? - I say they are still in earths "atmosphere" if you count the Van Allen radiation belts? Are you saying they went past these ?? What do you mean by "Blue illusion", its actually blue. The van Allen radiation belt has nothing to do with the atmosphere. In physics, the atmosphere is defined in two ways: 1) The Kármán Line which 100 km from sea level 2) The place where fiction starts to become measurable when a spacecraft/rocket is descending down to Earth (I dont know the exact height of this) I was using the second definition because for the spacecraft to orbit the Earth there needs to be very little friction, otherwise it would just go through orbital decay and slowly descend back to earth and the astronauts would not get any work done.so they must have been above the Earths atmosphere. In reality though, there's no concrete boundary-line where the atmosphere ends and outer space starts. The atmosphere doesn't even really end, its just progressively gets thinner and thinner. Even the Kármán Line is an arbitrary definition. The second definition makes more sense to me though because its the one used by aerospace engineers and applies more to this situation.
	Quote