Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site mordor.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!tektronix!hplabs!hpda!fortune!amdcad!amd!dual!mordor!space@mit-mc From: space@mit-mc Newsgroups: net.space Subject: Re: Light Sails Message-ID: <937@mordor.UUCP> Date: Tue, 5-Mar-85 03:12:36 EST Article-I.D.: mordor.937 Posted: Tue Mar 5 03:12:36 1985 Date-Received: Sat, 9-Mar-85 10:50:43 EST Sender: daemon@mordor.UUCP Lines: 23 From: Paul Schaublerochester!nemo writes: > There are these little globes with vacuum and a paddle/pivot mechanism > inside which work on this principle. The four paddles are arranged so > that the intersection of the two planes is the axis of rotation of the > pivot. Each paddle has a black side and a silver side with radial > symmetry. Placed in light, the paddle(s) on one side of the pivot > will reflect the light, the one(s) on the other will absorb the light. > The absorbing surface gets only the inelastic momentum change, or mv, > while the reflecting surface gets the 2mv momentum change. This > creates a torque on the paddle structure, and the little bugger > rotates. Available at novelty stores near you! > Nemo This says that the beast should rotate witht he white (reflective) side retreating. Take a close look at one. They rotate in the other direction! Now, would anyone care to provide an explanation?? Paul