[net.space] Relativity, re #247

@S1-A.ARPA,@MIT-MC.ARPA:jennings@AEROSPACE.ARPA (09/18/85)

From: Richard K. Jennings <jennings@aerospace.arpa>

	Re Steve Benz's proposal to lock onto color to determine relative velocity,
Two problems:

	Radial velocity is only one component of relative velocity -- it
	is not clear how angular velocity can be measure via colors;

	As the radial velocity approached the speed of light, the
	measurement instrument would have to become (in the limit)
	infinitely precise.

		-- Rich.