0

Can the rate at which time passes be changed?

For example, can time stop, slow down, or speed up? If so, how?

Is it really time that is shifting or is it the measuring devices?

Nat
  • 4,640
user3549018
  • 11
  • 1
    Welcome to SE.Physics! If you want to ask about time slowing down or speeding up, what do you mean by that? This is, we usually measure the rate at which things change by talking about their difference over time, e.g. as $\frac{\mathrm{d}}{\mathrm{d}t} ;$ so, if you want to ask about the rate at which time passes, it'd seem like you'd be asking about $\frac{\mathrm{d}t}{\mathrm{d}t}=1 ,$ so it's kinda like asking if $1$ can be made bigger or smaller. Presumably, you have multiple notions of time, and wish to compare the passage of one against another? – Nat Sep 28 '18 at 00:06
  • Possible duplicates: https://physics.stackexchange.com/q/235511/2451 and links therein. – Qmechanic Sep 28 '18 at 05:35

1 Answers1

1

Time dilation is the way the perception of time changes depending on the reference frame of the viewer. Different velocities mean different perceptions of time. For instance, if you see a clock moving at half of light speed relative to you, the clock will take longer than one second for it to say one second has passed, according to you. However, in the clocks reference frame (that is to say, to the clock or to anyone moving in the same direction with the same speed as the clock) it will be ticking as expected. It will actually see you moving slowly.

However, in the process of speeding up and then slowing down, everything ‘works out’ and you won’t exactly have time travel (at least not in the contemporary sense). You cannot go backwards in time; you cannot go forwards in time instantly. You can,by going very fast, leave your twin brother on earth on a spaceship and then return, where he will then be (in all way shape and form) older than you. However, he will always have aged; you cannot have left and come back older while your brother is the same age as he was when he left.

So, in a sense, you can speed up time; that is about it.

This is all special relativity. Maybe (doubtfully) there are other situations involving general relativity. I do not know.

Descartes Before the Horse
  • 585