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Wavelength in Orbit

  1. Feb 7, 2008 #1
    Have a look at this diagram I made: http://la.gg/upl/wavelength2.jpg [Broken]

    The scenario is that you are in circular orbit around the Earth and a radio signal is sent from the center of the Earth. If you have a clock with you that is synced up to a clock on Earth (we are ignoring relativity here), you will measure the frequency to be the same no matter how fast you are traveling. If you measure the distance between the point where you hit one peak and the point where you hit the next, however, you will measure a longer wavelength the faster you are going.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Feb 7, 2008 #2


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    Staff: Mentor

    I don't understand your diagram and don't see a question anywhere in there, but yes, there is doppler shift.
  4. Feb 7, 2008 #3
    I'm not asking a question, simply making an observation.

    As for the diagram, the three rectangles on top of each other (labeled 1, 2, and 3) are sequential images of the impulses advancing and the object moving perpendicular to the direction of the wave. In frame 1, the object is experiencing a peak (vertical line). In the intermediate frame (2), the object has moved a certain distance (although its distance from the Earth remains the same) and the impulses have advanced so that the object is now between impulses. In the final frame (3), the object has moved farther, and it is now experiencing another peak.

    The rectangle to the right of the other three shows the path the object would have had to take to pass through those same points if the waves weren't moving --- it is a bit confusing
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