Path: csiph.com!eternal-september.org!feeder.eternal-september.org!mx02.eternal-september.org!.POSTED!not-for-mail From: jimp@specsol.spam.sux.com Newsgroups: sci.physics Subject: Re: Can you push a spacecraft with light? Date: Fri, 22 Jan 2016 05:46:47 -0000 Organization: A noiseless patient Spider Lines: 31 Sender: Jim Pennino Message-ID: <7bs8nc-f8o.ln1@mail.specsol.com> References: Injection-Info: mx02.eternal-september.org; posting-host="db4120ef82bbc153014637d4cd15a795"; logging-data="9045"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+OOCZdNDH+DrNx79dAJu5U" User-Agent: tin/2.2.1-20140504 ("Tober an Righ") (UNIX) (SunOS/5.10 (i86pc)) Cancel-Lock: sha1:CKQ0YmvZRdTJcWiYMYzmzx2sDrg= Xref: csiph.com sci.physics:547138 Sylvia Else wrote: > On 22/01/2016 10:25 AM, jimp@specsol.spam.sux.com wrote: >> Sam Wormley wrote: >>> Can you push a spacecraft with light? >>>> https://www.youtube.com/watch?v=oIuvIDhcs8E >>> >>> >>>> What if you could power a ship using sunlight instead of wind? Well >>>> in space, you can! Solar sails or light sails are pushed with light >>>> from the sun. Photons provide a kick when they reflect off the sail >>>> pushing the sail like an air molecule in the wind pushes a sailboat. >>>> Find out how a solar sail works and about the future of this >>>> technology! >> >> Ancient news and childishly simplistic; real sails are airfoils. >> > Probably best not to use aerofoils in this application. They wouldn't > work at all well. Hence my comment the original post is childishly simplistic. > The best solar sail has a mirror surface and is completely flat. In > practice, some compromise on the flatness will almost certainly be made > for engineering reasons. While the best of real sails are nowhere near flat. > Sylvia. -- Jim Pennino