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Old September 18 2012, 07:55 PM   #23
gturner
Admiral
 
Location: Kentucky
Re: Warp Drive May Be More Feasible Than Thought, Scientists Say

newtype_alpha wrote: View Post
EJD1984 wrote: View Post
The one issue I just thought of is with communication. Would you have to stop to make a transmission?
No, relativistically the speed of light remains constant in all reference frames, even if you're FTL with respect to the receiver. Message transit time is the same either way (you might want to stop accelerating for a while, though, in case the warp field scatters your radio signals). The thing is, your signal would be redshifted by such an insane degree that it might be below the detection threshold of anything that might be able to receive and decode it. 10c is enough of a doppler shift to go from x-rays to ULF radio, and that would have certain complications for message integrity.
I think the redshift is easily calculated because the sender isn't undergoing time dilation. The sender traveling to Alpha Centauri sends 5 months (their perceived time) worth of data, which gets strung out from Earth to Alpha Centauri, so the end of their message arrives 4.2 years later, a factor of 10 (their velocity in C). So a 20 GHz signal arrives at a frequency of 2 GHz.
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