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BISMARCK
2007-Feb-09, 11:18 PM
I was reading about the effects of a human body being exposed to the vacuum of space, and from what I read, as long as normal pressure is restored within 15-30 seconds, there probably wouldn't be any permanent damage. It did mention that if you weren't in a shadow, you'd probably suffer severe sunburn within seconds, if you were roughly 1 AU from the Sun.

This makes sense.

My question is, how far out in the Solar System would you have to be to not be very quickly burned by direct solar radiation in a vacuum?

George
2007-Feb-09, 11:52 PM
Probably not as far as you might think. Although the peak intensity of the sun is in the blue (~ 480nm), its radiation intensity drops off quickly for the higher energy, shorter wavelength, light (ie UV).

Here (http://rredc.nrel.gov/solar/spectra/am1.5/) is a spectral irradiance plot showing the sun as observed in space (black line), from the surface when the sun is at zenith (blue), and when the sun is 37 deg. from the zenith (AM1.5 or equivalent to 1.5 atmospheres).

Just looking at this seems to show our atmosphere reduces UVA and UVB about 25%. [UVB is 280nm to 315nm, UVA is 315nm to 400nm].

So, perhaps about 2 au or more might do the trick. However, the damaging UVC light needs to be considered.