Time travel and the 2nd law of thermodynamics

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The discussion centers on the compatibility of time travel with the laws of physics, particularly the second law of thermodynamics, which states that entropy in a closed system tends to increase. A key argument presented is that traveling back in time does not necessarily violate this law, as the traveler would have always existed in the past timeline, meaning the overall entropy remains consistent. Additionally, the concept of traveling to a parallel universe is introduced, suggesting that if a time traveler brings back a greater amount of entropy from this alternate past, it could potentially align with the second law. This perspective opens up a theoretical framework for reconciling time travel with established physical laws.
jewfro420
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it is often stated that time travel is not forbidden by any law of physics.

but doesn’t the second law of thermodynamics forbid it because going back in time would involve a decrease in entropy?
 
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I think the only way around violating the second law goes something like this:

Suppose someone travels back in time from say the year 2000 to 1990. Does this increase entropy? No because you always existed in 1990 and the entropy of the universe reflects this. Its not like you did not exist in the first version of 1990 but existed in the later ones.
 
Suppose you go back into a parallel universe that looks exactly like the universe of 10 years ago.
And suppose you bring a lot of entropy back with you, making sure the entropy of this parallel past is greater than the entropy in the now.

I think that would preserve the law...
 

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