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: Stephen Hawking's Plan For Interstellar Travel Has Some Earthly Obstacles Date: Fri, 15 Apr 2016 00:36:46 -0000 Organization: A noiseless patient Spider Lines: 26 Sender: Jim Pennino Message-ID: References: Injection-Info: mx02.eternal-september.org; posting-host="db4120ef82bbc153014637d4cd15a795"; logging-data="10769"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/unh6Qs1Q2NmIXCvP4dhGF" User-Agent: tin/2.2.1-20140504 ("Tober an Righ") (UNIX) (SunOS/5.10 (i86pc)) Cancel-Lock: sha1:2dsUSxfRUkeKy0IqgkVwNcalWPU= Xref: csiph.com sci.physics:570604 Sam Wormley wrote: > Stephen Hawking's Plan For Interstellar Travel Has Some Earthly Obstacles >> http://www.npr.org/sections/thetwo-way/2016/04/14/474227319/stephen-hawkings-plan-for-interstellar-travel-has-some-earthly-obstacles > > >> Houston, We Had A Problem ... Last Year >> >> Once the hundreds or thousands of probes leave our solar system, they >> would be on their own in more ways than one. Physics dictates that >> communications between Earth and the probes can't happen faster than >> the speed of light. That means if one of the probes runs into trouble >> a light year into its journey, then it will take a year for its >> distress call to reach home. It will take another year for mission >> control's instructions to reach the little craft. >> >> It's safe to say that in the two years it takes to get help, the >> probe will have either fixed itself or died. Assuming you have an antenna large enough to get any signal back, which so far is not in evidence. And it also means it is pointless to send any commands at all after a certain distance. -- Jim Pennino