This question is an exact duplicate of:
- Struggling with relativity [closed] 2 answers
Ok so there is something that I don't really understand , suppose we have the proper time A :8 years and gamma factor 2. Now I understand that the time slow downs for the relative time (t') so the relative time (dilated time) is 16 years. However guy who is moving in the t' frame is actually 8 years old and the guy in proper frame is 16 years which is opposite from what is said above so why do we say that t' is 8 years old if his dilated time is 16 ? How can we transform between the age and time ? Maybe my misunderstanding is the fact that I don't interpret t and t' in the good way ?
What I understand from this is that A: 16(t')=2x8(t) so in john frame after 16 years Mary age by 8 years ? Isn't t' the dilated time or is it the age what is it specifically and what do they mean in the book exactly