Time travel and the 2nd law of thermodynamics

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SUMMARY

The discussion centers on the relationship between time travel and the second law of thermodynamics. It asserts that time travel is not inherently forbidden by physics, but raises the question of entropy. The argument presented suggests that traveling back in time to a point where one already existed does not violate the second law, as the entropy of the universe would remain consistent. Additionally, the concept of parallel universes is introduced as a potential solution to reconcile time travel with thermodynamic principles.

PREREQUISITES
  • Understanding of the second law of thermodynamics
  • Basic knowledge of entropy and its implications
  • Familiarity with concepts of time travel in theoretical physics
  • Awareness of parallel universe theories
NEXT STEPS
  • Research the implications of the second law of thermodynamics on time travel
  • Explore theories of parallel universes in quantum mechanics
  • Study entropy and its role in physical laws
  • Investigate existing theoretical frameworks for time travel in physics
USEFUL FOR

The discussion is beneficial for physicists, students of theoretical physics, and anyone interested in the intersection of time travel and thermodynamic 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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