Can Memory Invalidate the Symmetry in Special Relativity's Thought Experiments?

  • Thread starter Noa Drake
  • Start date
  • Tags
    Sr
In summary: Because, as phinds pointed out, this is the central point of SR - that ALL inertial frames are equally valid. It's not "either/or" it's "as well as." So, if the station is moving away from you but you are not accelerating (i.e. you are in an inertial frame), then you can say that you are not moving and that the station IS moving away from you. You can say it, but so could someone on the station. The point is that both statements are equally valid. And this is the central point of SR.EDIT: PS: you can also say that the station is stationary and that you are moving away
  • #36
Noa Drake said:
I know that i had to startup the train from 0 km/h to start leaving the station.

No, you don't know this. All you know is that you had to start up the train from 0 km/h *relative to the station*. You don't know whether you started "moving" in any absolute sense when you started leaving the station, or if you were "moving" when you were in the station, and gradually stopped "moving" as you accelerated, until you reached a state of "rest" when the train stopped accelerating. You can't just assume that moving at 0 km/h relative to the station means you are "really at rest". (If you're inclined to say that you can, consider that the station is on a rotating Earth, which is moving relative to the Sun, which is moving relative to the galaxy, which is moving relative to other galaxies. The fact that the station *seems* to be at rest to you is not a good reason for claiming it is "really at rest" in any absolute sense.)

In other words, just knowing that you accelerated in the past doesn't show that you are "moving", because you don't know which state of motion is "really" at rest to begin with. All acceleration does is change your state of relative motion; it doesn't, and can't, let you determine which state of relative motion is "really moving" or "really at rest".
 
Physics news on Phys.org
  • #37
Ok, thank you for these various comments, i am learning.
 
  • #38
Excellent. That's what all the Science Advisors and Homework Helpers and Mentors here love to hear. They spend a lot of time here trying to do just that and it is sometime an underappreciate task. I, on the other hand, am just here to kibitz :smile:
 
Back
Top