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Communications from Space

  1. Apr 29, 2009 #1
    I have always wondered about this. When we went to the moon how did we communicate back to earth?

    On the same note, what are the ways to communicate from the outer space? i.e from moon, mars, pluto?

    If we managed to visit a place 20 light years away, how could we communicate back to earth based on current technologies we have?
  2. jcsd
  3. Apr 29, 2009 #2


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    Radio - but it would take awhile for the signal to get back.

    For line of sight communications you could also use lasers but except possibly for some
    military kit I don't think anything does
  4. Apr 29, 2009 #3
    To my understanding Radio signals use light. So would it be right to say that the maximum speed at what we can communicate with anything in space is at speed of light?

    Would it be right to say that if we somehow managed to send a spaceship to a planet that is 10 lights years away, every communication that will take place will have a delay of at least 10 years?
  5. Apr 29, 2009 #4


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    Yep, on every count.

    Even a phone conversation which goes through a comsat suffers a noticeable lag, about .5s. This is a reason that a ISP using a satellite dish in not good for online gaming.
  6. Apr 29, 2009 #5


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    Staff: Mentor

    Just to clarify, radio signals and light are just two different forms (frequencies) of the same thing: electromagnetic radiation.
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