# Time dilation Vs Time duration Or watching a movie at the speed of light

I am not a physicist but a physics enthusiast and while trying to understand time dilation I came up with this thought experiment in order to understand things better based on the answers to my 2 questions below:

1. a boy is standing still on Earth
2. a girl is about to leave Earth on a spaceship
3. the boy starts watching a 2-hour movie
4. the girl starts watching the same move inside the spaceship, at the same time
5. as soon as the girl starts watching the movie, she leaves earth onboard her spaceship and accelerates to speeds near the speed of light
6. the boy remains on earth watching the movie
7. the girl is inside the spaceship watching the movie while travelling at a speed near the speed of light and while she is watching the movie she uses a camcorder to film the screen that is projecting the movie
8. back on earth, the boy finishes watching the movie and at that exact point sees the girl landing back on earth
9. due to time dilation the time experienced by the girl inside the spaceship was more than 2 hours. What it means is that while on the spaceship, the girl watched the movie, the movie ended and the girl had yet to arrive and land back on earth. She had time left to do more stuff inside that spaceship like maybe take a nap or something. And after some time had passed on that spaceship and after she was done watching the movie, only then did she arrive back on earth.
10. the girl is now back on earth, exits the spaceship sits next to the boy, takes out her camcorder and they both sit and watch the movie she recorded on her spaceship

Question #1: Is point 9 correct?

Question #2: When the boy and the girl sit down on earth to watch the camcorder-movie, how long will that movie last and will the playing-speed of the movie be normal? (please excuse me in advance if this 2nd question in particular is completely ridiculous and laughable)

• Both of them would agree that the movie lasted 2 hours on their screen assuming they have their own TV that they're taking with them. Commented Apr 17, 2020 at 20:22
• Two things. The girl comes back younger, not older - or to put it another way, the boy's film finishes sooner than the girl's. Secondly, whichever camcorder movie they watch, the boy's camcorder movie will be longer than the girl's, and that longer movie will have used more tape. There will be no difference in the apparent speed of the camcorder movies - the discrepancy will be accounted for entirely in the fact that the boy will have consumed more tape than the girl whilst recording the whole period. Commented Apr 17, 2020 at 20:23
• If G returns when B finishes their movie, G will have only gotten through a fraction of the movie.
– d_b
Commented Apr 17, 2020 at 20:23
• Steve thanks for your answer. Just to clarify, there is no "boy" camcorder movie. There is only the one recorded by the girl on the spaceship and I would like to know how long will that last while they watch it together back on earth. d_b your answer is the opposite of Steve so now I'm more confused :D Commented Apr 17, 2020 at 20:33
• I think Steve and I said the same thing.
– d_b
Commented Apr 18, 2020 at 1:56