Last Updated : August 21, 2001
What is space? (the basics)
Space is the region beyond the earth's atmosphere.It begins where the atmosphere ends, continues in all directions and has no known boundry.
...So where does the atmosphere end?
The atmosphere does not have a fixed/perfect boundry.The air has maximum density at sea level which decreases with height to negligible values.
A man is technicaly an astronaut if he crosses a height of 80 km.However,a satellite cannot be put in orbit at this level.While at 160 km above sea level,a satellite can stay in orbit for a few months before burning up.The region beyond 200 km above sea level(atleast) can be called space.
..how high is that?...
200 km/124 miles/655,000 ft is pretty high by aeroplane standards.By comparison,the Concorde flies at 17.9 km/11.1 miles/58,500 ft which itself is more than twice most commercial jumbo aeroplanes fly.Even at this height one can see faint curvature of the earth.
China's Shenzhou / 921 Manned Space Orbiter
