1
$\begingroup$

Everyone know the standard Twin Paradox. I have my clock synchronized here on Earth with my twin. I leave Earth, Travel for a time at 0.9c, turn around, come back at .9c and then my clock is slow compared to the twin.

What can I do so that the situation is the same, but my twin's clock is the one that is slow. So, start synchronized, do 'something', turn around, do 'something', and my twin's clock is slow.

I was thinking that maybe being frozen to near absolute zero, maybe? To look at it another way, if something is travelling at c, it experiences zero time. Is it possible for something to experience the opposite, ie infinite time? If c is the maximum speed, is there a minimum speed? Are we already traveling at it?

$\endgroup$
  • 3
    $\begingroup$ "Do something" the first time is *watch you twin accelerate away from you" and the second time is "watch your twin acceleration to reverse course and return to your vicinity". What else? $\endgroup$ – dmckee Jul 14 '16 at 21:52
  • $\begingroup$ Are we already traveling at it Do you mean through space or through time? We are always travelling through 4D spacetime at c. physics.stackexchange.com/q/33840 $\endgroup$ – user108787 Jul 14 '16 at 21:56
  • $\begingroup$ it depends, if the time started at the big bang, then time intervals are finite. But I like the idea of an observer who has experienced all its infinite past. $\endgroup$ – Wolphram jonny Jul 14 '16 at 23:46
  • $\begingroup$ Try dragging your feet. $\endgroup$ – WillO Jul 15 '16 at 12:53
1
$\begingroup$

In special relativity, you can't do it. Much like a straight line is the shortest distance between two points in Euclidean geometry, a straight (nonaccelerating) worldline is the longest distance between two points in Minkowskian geometry (the geometry of spacetime). If one twin accelerates and the other doesn't, the one who doesn't accelerate will be older, always.

In general relativity (more precisely, in curved spacetime), it is possible. For example, two clocks in different orbits around a central mass will measure time at different rates in general. If one twin stays in a circular orbit near the Sun, and the other heads out to a more distant orbit, stays there for a long enough time, and then heads back, the second one will be older, even though they accelerated (as measured by an accelerometer) and the first twin didn't. I think that they would have to wait for an extremely long time, though, since otherwise the special-relativistic part of the trip dominates.

$\endgroup$
0
$\begingroup$

There are two very similar question today itself. I am pasting my answer from the other one here -

It is shown in movie "The contact" where it passes just a second or so on earth, but during the same time, the astronaut records many hours of static. What people on earth saw was that the space ship crashed before even taking off, but astronaut experienced having made a journey to other words. As far as I remember, the concept is not clearly described in the movie, you may try watching it. What I am suspecting is - We know gravity slows down time. The space ship must have created anti gravity (or negative gravity) that would have given the opposite effect, i.e. sped up the time. Therefore stretching a second of earth time to many hours in that environment inside the ship. So, you need to be that astronaut in order to slow down your twin's clock as compared to yours.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.