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Relativistic travel, perception and the constancy of light

  1. Apr 18, 2014 #1
    Suppose you were to board a ship on Earth departing for a star system 1,000 light years away. You accelerate at 1g for the first 500ly, then decelerate at 1g for the second 500ly. Observer on Earth will claim 1,001.936 have passed during your voyage, whereas you will have experienced 13.452 years within your reference frame (assuming this is correct). Destination also provides a inertial reference frame? Destination may claim 1,001.963 years have transpired since your departure.
    Here is the question:
    if you arrive at your destination and immediately gaze back at the Earth in your super-telescope, what do you see?
    I would guess that, as your journey has not affected the passage of light reflected by the Earth to the destination, that you would be viewing events from precisely 1,000 years ago, i.e. 1.936 years after you left Earth, despite your having experienced more than 13 years of travel time. Also, had you observed your destination immediately before departure and took a picture, that picture would represent a state 1,000 years in that place's past. Now, upon arriving there, I would assume you are witnessing 2,001.936 years of development relative to that picture.
    If you were to immediately turn around and go back to Earth via the same process, would you not return to find that a total of 2,003.872 years had elapsed in your absence which, by your reckoning amounted to 26.9 years.
    Mainly I am curious as to whether my intuition about looking back at Earth upon landing is correct, though I admit my reasoning may be vulnerable to any number of flaws pertaining to any number of points here mentioned.
    Pleas someone correct any mistaken assumptions which may have been expressed here.
  2. jcsd
  3. Apr 18, 2014 #2


    Staff: Mentor

    Hi, Camel_City, and welcome to PF!





    Nope, you got it all right. :smile:
  4. Apr 18, 2014 #3
    Thank You

    Thanks very much for the reply. I really appreciate it!
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