Reverse Universe: Acceleration and Time Reversibility

In summary, the conversation discusses the concept of reversibility in physical laws and how it can be tested by imagining a "Reverse Universe". The example of acceleration is used to show that the magnitude of the acceleration would be the same in both the reverse universe and the existing universe, but just in a reverse order. However, the speaker raises a question about the velocity changes in the two universes and seeks clarification.
  • #1
Vincit
22
0
Among the physical laws it is a general characteristic that there is reversibility in time; that is, should the whole universe trace back the various positions that bodies in it have passed through in a given interval of time, but in the reverse order to that in which these positions actually occurred, then the universe, in this imaginary case, would still obey the same laws.

To test this supposed reversibility, we may imagine what we call 'Reverse Universe'. So, for example, if we had an imaginary universe, that universe would experience the same position of all bodies at various moments of time the same as the real universe; in reverse order.

But what would happen to a problem such as acceleration? I know that acceleration is the change of velocity divided by the interval of time required to produce this difference. So, if velocity A changed to velocity B, the equation(vectorially) would be B-A/T. So, in the corresponding motion of the reverse universe, wouldn't the velocity change from -B to -A, so that the acceleration is [(-A)-(-B)]/T. This is equal to B-A/T. Does that show that the magnitude of the acceleration will be the same in the reverse universe and the existing universe, but just reverse in order?

:/ I am being sidetracked by slight nuisances; help would be appreciated.
 
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  • #2
Most laws are like that except the second law of thermodynamics, part of which states that for spontaneous (read: possible) events will cause a net increase in entropy in the universe.

The maths from your acceleration scenario isn't too surprising. If we take some numbers, say A = 2m/s, B = 10 m/s and T = 4s, we get an accelleration of 2m/s^2. Now going from -10m/s to -2m/s is still an increase in speed of 8m/s in 4s, giving the same accelleration.
One is an increase in speed in the positive direction and the other is a decrease in speed in the negative direction, which is the same accelleration.
 
  • #3
I have a question, why the reverse U's velocity changes form -A to -B while the real U changes from B to B? Shouldn't it be from -B to -A ?
 

1. What is the concept of a "reverse universe" in relation to acceleration and time reversibility?

The concept of a "reverse universe" involves the idea that the laws of physics operate in the exact opposite way in a hypothetical universe where time runs backwards. This means that instead of objects accelerating and moving forward in time, they would decelerate and move backward in time.

2. How does the theory of time reversibility explain the phenomenon of acceleration?

The theory of time reversibility suggests that the concept of acceleration is relative and can be reversed. In our universe, we experience acceleration as an increase in speed over time, but in a reverse universe, objects would experience deceleration as a decrease in speed over time.

3. Can acceleration also be reversed in our universe?

No, in our universe, the laws of physics do not allow for time to run backwards. While some processes may appear to be reversible, such as simple harmonic motion, the overall direction of time is always forward. This is known as the "arrow of time" and is an important concept in understanding the nature of the universe.

4. How does the concept of time reversibility relate to the laws of thermodynamics?

The laws of thermodynamics state that in a closed system, entropy, or disorder, will always increase over time. In a reverse universe, entropy would decrease over time, meaning that order and structure would increase. This goes against the second law of thermodynamics and is one of the reasons why a reverse universe is considered to be hypothetical rather than a physical reality.

5. Is there any evidence or experiments that support the idea of a reverse universe?

Currently, there is no experimental evidence to support the existence of a reverse universe. The concept is purely theoretical and is often used as a thought experiment to explore the fundamental laws of physics and the nature of time. However, some theories, such as the Wheeler-Feynman absorber theory, suggest that the laws of physics may be reversible on a quantum level.

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