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Question about time dilation?

  1. Nov 5, 2014 #1
    If im an astrounaut in orbit, i would "see" events down at earth happening at a slower rate. For example; if i watch a dragrace between two cars down at the surface from the orbit, i would see the cars driving slower then what i would see if i were standing at the racetrack. Offcourse, when i say "see" i realize that the actual time difference is very small, but non the less, there Is an OBSERVABLE difference? Is this correct according to general relativity?
     
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  3. Nov 5, 2014 #2
    When you travel at a velocity v, relative to an event. You observe a 'longer' time, than when you are not moving relative to the event. For example if you watch a movie (looking from the earth) which is playing in a space ship, the movie will seem to take longer. So in your example when you look at the racing-cars, the time you measure, will be longer, however there is also this thing called 'length contraction', which means that the length (of the racing-cars) you measure will be shorter. If you want to know which velocity you will measure you need to use the Lorentz velocity transformation, I don't know it out of the top of my head, but you can find it on the web. I hope this answered your question.
     
    Last edited: Nov 5, 2014
  4. Nov 5, 2014 #3

    ghwellsjr

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    No, this isn't right. First, you can't see Time Dilation, it's the result of either a calculation that you have to perform on what you see and the assumption that what you see is light that travels to you at the speed of light or it is an establishment of a frame of reference in which light travels at the speed of light.

    If you are in orbit around the earth, you will see the cars driving faster as you approach them and then slower as recede away from them. Then, of course, you won't be able to see them while you are going around the earth. If you had devised a different scenario where you are in "orbit" around an object that you could see all the time and you remained the same distance away, then you would always see time for that object going faster than your time but the object would see time for you going slower and by the same factor that the object would calculate for Time Dilation. Time Dilation only has a simple relationship when the observer is inertial, traveling in a straight line at a constant speed (which could be zero) according to an Inertial Reference Frame.
     
    Last edited: Nov 5, 2014
  5. Nov 5, 2014 #4

    ghwellsjr

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    This is not right completely right. The first part is right about earthlings seeing a moving on a space ship take longer but the astronauts would see a movie on earth take less time. This is just like the Twin Paradox where the earthlings see the traveler take longer to die but the traveler sees the earthling take less time to die. See my previous post.
     
  6. Nov 5, 2014 #5
    aaaah yes, I see where I went wrong, I was assuming the space ship wasn't changing direction, but if it's in orbit, it is changing direction. Thank you for pointing out my mistake.
     
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