5
$\begingroup$

Let me pose this question as a hypothetical.

Your ship warps/jumps to a planet 50 light years away. You set up a radio signal receiver. Theoretically, the radio is going to receive radio-waves from Earth from 50 years ago.

My question is even with a powerful receiver, would the signal be clear enough that I could listen to 1968 radio stations without problems or would the signal have degraded to an almost undecipherable static? if so, what factors would be the cause of the degradation? Can gravitational or other interstellar phenomena (radiation?) degrade a radio signal?

$\endgroup$
10
$\begingroup$

No, you can’t pick up radio broadcasts from fifty light years away without a receiver that’s more powerful than anything we currently know how to build. The degradation is caused by the inverse square law — a broadcast that’s designed to be picked up 1,000 miles away will be about 22 orders of magnitude weaker at a distance of fifty light years. See this Physics Stackexchange question.

$\endgroup$
  • 6
    $\begingroup$ More than powerful I'd use the term sensitive. $\endgroup$ – L.Dutch - Reinstate Monica Sep 22 '18 at 6:28
  • $\begingroup$ @L.Dutch I’m just using the same terminology as the question, which talks about a “powerful receiver”. $\endgroup$ – Mike Scott Sep 22 '18 at 6:56
  • $\begingroup$ Ah, yes. 'Sensitive' would be the right term, thank you. $\endgroup$ – Moin Sep 22 '18 at 10:31
  • 1
    $\begingroup$ Radio transmitters can have a power of a few kilowatts, and with a dish the size of Arecibo it might well work. I think it's more of a problem that most radio waves don't get out of earths conductive ionosphere. $\endgroup$ – Karl Sep 22 '18 at 19:29
  • 1
    $\begingroup$ @Karl No, it would be much too faint for Arecibo to pick it up. See the answer to the question linked in my answer. $\endgroup$ – Mike Scott Sep 23 '18 at 5:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.