Originally posted by Empire:
Thanks for the posts but I still have some questions.
Imagine a spacecraft moving close to the speed of light. Observer 1 is in the spacecraft and observer 2 is outside. I am trying to keep in mind that speed is distance/time and the person is aging slower traveling near the speed of light.
They both are holding a flashlight in the same direction and turn them on exactly when they are next to eachother.
Will observer 1 see the 2nd flashlight moving across space in slow motion? In relation to observer 2's stationary position will the 1st flashlight be moving faster? Will it apear to observer 2 that the 1st flashlight is affected by a dopler effect because the source of the light is moving close the the speed of the light? Thanks in advance.
I am sorry I was off-line yesterday. Both observers observe from their respective reference frames within which each one is of the opinion that he is stationary. If both switches on a flashlight along the direction in which they are moving, the trailing observer will not see any light coming from the leading observer. The leading observer will see the light from the trailing observer approaching him with a speed c; however, it will be redshifted (Doppler shift) because the leading observer will see the slower moving trailing observer moving away from the leading observer. If the leading observer points his flashlight backwards towards the trailing observer, then the trailing observer will also see this light travelling towards him with the speed c. It will also be redshifted because the trailing observer will see the leading observer moving away from the trailing observer. I hope this is of help?
