B Energy Conservation w/ Charged Battery Time Travel

[Lars Krogh-Stea]

TL;DR Summary

What are the concerns regarding energy conservation when sending a charged battery through time, both forwards and back in time. (Not sure what level this is).

Hi!

I want to start with saying that I'm not an expert on these type of problems, but I will be gratefull for some calarifications.

I've heard that there's nothing in psysics that says that time travel is impossible. I want to make a case with the time traveling battery. Could be any mass with inherent energy, but a charged battery makes the image clearer, I think.

First, forewards in time:
You charge a battery, some space traveller traveling fast through space takes the battery on a long journey and uses less time on the voyage than has passed on earth. The battery (and it's stored energy) has traveled through time, but the energy is never duplicated and everything is okay.

I've also read that even if energy is created as the universe is expanding, when timespace is not changing, energy is conserved/constant.

So, we'll send the battery back in time:
You charge a battery on the 3rd of may, and the 4th of may you send it through a wormhole that exits on the 2nd of may. Then, on the 3rd of may there will be two instances of the battery, with the same energy charge. On this day there is no connection to the wormhole and no extraordinary manipulation of spacetime. How is this legal within the laws of physics?

Thank you for your time :)

 

[Vanadium 50]

I've heard that there's nothing in psysics that says that time travel is impossible

Really? From a reliable source?

Without a working, valid theory of time travel, one cannot answer questions about how it might work.

 

[Nugatory]

I've heard that there's nothing in psysics that says that time travel is impossible.

You’ve heard wrong, but unless you can tell us where you got that from we can’t tell whether it was a bogus source or you’ve misunderstood something from a valid source. In fact, it is stuff like

So, we'll send the battery back in time:
You charge a battery on the 3rd of may, and the 4th of may you send it through a wormhole that exits on the 2nd of may. Then, on the 3rd of may there will be two instances of the battery, with the same energy charge. On this day there is no connection to the wormhole and no extraordinary manipulation of spacetime. How is this legal within the laws of physics?

and many similar paradoxes (the reverse causality paradoxes, where for example I kill my grandfather before my father is born may be even more problematic) that lead most physicists to believe that time-machine type time travel where I or a battery can go back and meet my previous self is physically impossible.
Of course that doesn’t stop us from having fun speculating about the possibility, but doing so is fun not physics.

 

[Ibix]

You'd first have to describe in detail a spacetime containing a traversable wormhole with an exit in the causal past of the entrance. If such a solution exists then local conservation of energy is trivially satisfied, but you'd need to derive a global conservation law for such a spacetime (and there are much simpler spacetimes for which no such law is known) before you could worry about whether that held or not.

In short, there's a lot of mathematical heavy lifting to be done before you can even consider your question. And depending on how the spacetime works your question may not have an answer in the terms you want.