🚀 go-pugleaf

jwt@duke.cs.duke.edu (Jeffrey W. Tannehill) writes:
: 
: 
: 	For Christmas I received a Space Shuttle model with instructions to
: paint the underside black.  This brought up the question "Why is the
: bottom of the Shuttle black?"  It occurred to us that a black surface might
: absorb a lot more radiation and that in space there might be greater
: exposure to radiation than on earth, so why isn't the whole shuttle white
: or perhaps silver to reflect as much as possible?


	Colour affects heat absorption in cases where the heat is being
radiated. The shuttle experiences heat absorption due to friction.
The SR-71 is black. The skin of the plane is aligned perfectly so
that when the skin begins to ripple (sortof like coorogated sheet
metal), the ridges and valleys are set up so that they are in line
with the air flow.    If you take a sheet of white paper and a
sheet of black paper and rub each on a smooth surface they should
both heat at the same rate....

				Ryan