Reporting my own post to bring this to the attention of a moderator.

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SUMMARY

This discussion centers on Albert Einstein's views on time travel and the implications of his theories on spacetime. Participants highlight that while Einstein rejected the notion of time machines, his theories suggest time travel could be feasible under certain conditions, such as the existence of wormholes and the manipulation of spacetime geometry. Key concepts include the twin paradox, light cones, and the relativity of simultaneity, which illustrate the complexities of time travel and causality in physics. The conversation emphasizes the need for precise definitions and understanding of terms like "time-like," "light-like," and "space-like" separation in the context of relativity.

PREREQUISITES
  • Understanding of Einstein's Theory of Relativity
  • Familiarity with concepts of spacetime geometry
  • Knowledge of light cones and their implications in physics
  • Basic grasp of causality and paradoxes in theoretical physics
NEXT STEPS
  • Research "Einstein's Theory of General Relativity" for foundational knowledge
  • Explore "Minkowski spacetime" to understand geometric interpretations of time
  • Study the "twin paradox" and its implications for time dilation
  • Investigate "tachyons" and their theoretical role in faster-than-light communication
USEFUL FOR

This discussion is beneficial for physicists, students of theoretical physics, and anyone interested in the complexities of time travel and the implications of Einstein's theories on modern physics.

  • #31
Ibix said:
Did your phone have to be there in 1970 for its clock to measure time since then?

But the hardware/software that calculates the time had to be there before that time.

Ibix said:
Regarding post 25 - as I said, no, this has nothing to do with finite or infinite. Look up Einstein's train.
Except my "finiteness" argument. Is it correct?
I am editing it. Maybe it should be on a separate thread.
 
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  • #32
e-pie said:
But the hardware/software that calculates the time had to be there before that time.
You are trying to say that because VAX/VMS happens to use November 17, 1858 (it is a 64 bit integer measured in 100 nanosecond ticks) as its base date that there must have been a VAX back then? Not so.

Edit: Before we dive further into the relevance of epoch times in operating system timekeeping, it is past time for you to Google Einstein's train though experiment and get a handle on the relativity of simultaneity.
 
  • #33
Okay got the point. @jbriggs444 and @Ibix. Thanks to both.

And the new post 25?
 
  • #34
e-pie said:
And the new post 25?
i.e.
e-pie said:
The way I look at time(meaning how I define/measure it) depends on my choice of how I try to define each. As each choice is unique, we won't get any particular choice to be the standard/base.
The time coordinate in a coordinate system depends on the choice of coordinate system, yes.
The laws of physics fail to pick out a preferred coordinate system, yes.
 
  • #35
jbriggs444 said:
it is past time for you to Google Einstein's train though experiment and get a handle on the relativity of simultaneity

Almost midnight here. I will do it later. Let is stop the discussion here. I will start another thread/continue after I read Einstein's train experiment and clear my head a bit.I mean I tried but I am feeling sleepy and Wikipedia is not helping.Thanks.A Request: I think that, if this discussion is restricted between us three, it will not create any confusion(to me/any future viewers). Multiple opinions on same topic do tend to get messy and different commentaries can be hard to read(for me).And I am getting positive feedback from both.
Thanks. Logging of for now.
 
  • #36
e-pie said:
Off topic

Why is each post duplicating?Happening to me also.
It was likely due to a forum speed issue that should be cleared up now. If you see any other double-posts, just click the Report link to bring it to the attention of the Mentors so we can fix it up. Thanks! :smile:
 
  • #37
Sorry to keep both waiting. I studied Einstein's Train Thought Experiment from Wikipedia.

In short what I understood:

Two lightnings struck on a train moving uniformly ie inertial. To the standing observer outside of train frame the events have two space coordinates but same time coordinates but as the train is moving uniformly, to the observer in train the events have two time coordinates.

That is, simultaneity depends on reference frame?

Please comment if anything is wrong
 
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  • #38
Questions coming to my mind are off-topic(this post).

I will try to start new threads regarding those questions.

For the time being, please comment to post 37.Correct me/add something extra.

After your comments, I will end this discussion here and start new threads about relevant questions.Thanks to both. And the mentors, for their technical help.
 
  • #39
e-pie said:
That is, simultaneity depends on reference frame?
Yes.

New threads should probably go in the relativity forum - it's not general discussion. This thread probably should be moved there, actually.
 
  • #40
Ibix said:
This thread probably should be moved there, actually.

Right I started this thread to get some definitive sources vide post 1. But the discussion culminated into a "scientific" one.
Thanks to both.

Any mentor want to do it?

Ibix said:
This thread probably should be moved there, actually.

Thanks for your reply. I will start new threads as promised and in time.

Am reporting my own post to get this into moderator's notice.
 
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