Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!markh From: markh@csd4.milw.wisc.edu (Mark William Hopkins) Newsgroups: sci.space Subject: Re: approaching "C" Message-ID: <949@csd4.milw.wisc.edu> Date: 14 Feb 89 00:21:31 GMT References: Sender: news@csd4.milw.wisc.edu Reply-To: markh@csd4.milw.wisc.edu (Mark William Hopkins) Organization: University of Wisconsin-Milwaukee Lines: 19 In article rg20+@andrew.cmu.edu (Rick Francis Golembiewski) writes: >Here's a question I've alaways wondered about relativity: >Suppose there are two space ships, one going at .6 C (an attainable >theoretical velocity) and one going .6 in the opposite direction, >what would observers inside each see? Each would "see" the other going at 1.2/(1 + .36) C. See is a word to be taken lightly, because you can't see what's going on instantaneously. For example as you look up into the sky at the sun, it may have already gone nova up to 8 minutes ago. ON APPROACHING C: Relativity says you can't pass beyond C, because no matter how close you get to it, the difference between your speed and C is still C. In relativity, the "difference" between two speeds, v1 and v2, is: (v1 - v2)/(1 - v1*v2) expressed as a ratio in terms of C. When v1 is 1C, the difference becomes 1C.