crummer@AEROSPACE.ARPA (06/08/85)
From: Charlie Crummer <crummer@AEROSPACE.ARPA> > Date: Thu, 30 May 85 15:40:22 EDT > From: Doug Gwyn (VLD/VMB) <gwyn@Brl.ARPA> > Subject: Re: Reversal > Andrew Knutsen is right; a mirror does not reverse right & left > but appears to do so only because of the way we think about > comparing the image seen "in" the mirror against the original > object, namely via a 180-degree rotation about a vertical axis > combined with a translation to superimpose the two. A mirror reverses right and left HANDEDNESS. It is sort of like turning the image inside-out. A left glove becomes a right glove when it is turned inside-out. In differential geometry the term for mirror reversal is screw-sense transformation; in physics it is called parity. > Could we leave the SDI discussion out of net.physics? It's hard when the subject is Right and Left. --Charlie