Question regarding the arrow of time

In summary, the conversation revolves around the concept of the arrow of time and whether it could be different in different regions of the universe. There is discussion about the possibility of a forward and backward arrow of time coexisting, and how this could affect observations in the universe. The idea of retrocausality is also briefly mentioned and dismissed.
  • #1
Nasher
19
0
How about this idea...
With regards to this thing called, the arrow of time!

Could the universe have different arrows of time for different regions of the universe?
This regions of the universe where the Earth is, the arrow of time is going say forward.

Could there be other far off regions of the universe that have the arrow of time going backwards?

Imagine if the universe was composed of a forward arrow of time sub-universe and a backward arrow of time sub-universe superimposed upon each other!

If there were galaxies in regions of the universe that have the arrow of time going backwards,
from our perspective instead of the stars in those galaxies emitting light, they would be absorbing light,
and therefore their light would not be visible to us here in this forward arrow of time region of the universe.
 
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  • #2
What would be the observational consequences [to us] of these different 'arrows of time'?
 
  • #3
The observational consequence would be if we went somewhere and found clouds of random looking debris and gas coalescing into unlikely arrangements, light bizarrely focusing itself onto dwarf stars until they bloat and evaporate into uniform gas clouds, planets with dirt that suddenly arranges itself into big living organisms that shrink and then are taken into even newer organisms..

Nothing stopping this happening, it's just incredibly improbable.

What I can't explain is why it seems our universe was far, far more improbable than that when it began (more so even than the anthropic principle justifies).
 
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  • #4
What way does the arrow of time point in a vacuum?

Could it be that there is no arrow of time in a vacuum?

Could the universe have different arrows of time for different regions of the universe depending on the type of matter there?

This regions of the universe where the Earth is, the arrow of time is going say forward, and let's call the type of matter here, forward matter.

Could there be other far off regions of the universe that have the arrow of time going backwards?
And the type of matter in those regions could be known as reverse matter.

Imagine if the universe was composed of a forward arrow of time sub-universe and a backward arrow of time sub-universe superimposed upon each other!

If there were galaxies in regions of the universe that have the arrow of time going backwards, from our perspective instead of the stars in those galaxies emitting light, they would be absorbing light, and therefore their light would not be visible to us here in this forward arrow of time region of the universe.
 
  • #5
Chronos said:
What would be the observational consequences [to us] of these different 'arrows of time'?

I reckon that they would be difficult to observe because from our perspective, they would be absorbing light.

Maybe, the effects of their gravitational field could be observed.

Maybe, if theoretical physicists were to work through the mathematics, the might expect to find certain results that would be complementary to the observed structure of the universe.
 
  • #7
As, it seems, do I [dismiss the idea].
 

1. What is the arrow of time?

The arrow of time is a concept in physics that describes the direction in which time flows. It is often referred to as the "one-way direction" of time, meaning that time only moves forward and cannot be reversed.

2. What causes the arrow of time?

The arrow of time is caused by the second law of thermodynamics, which states that the total entropy (disorder) of a closed system will always increase over time. This means that as time passes, things become more disordered and less organized.

3. Can the arrow of time be reversed?

No, according to our current understanding of physics, the arrow of time cannot be reversed. This is due to the second law of thermodynamics, which dictates that entropy will always increase over time and cannot be reversed.

4. Is the arrow of time the same for everyone?

Yes, the arrow of time is a universal concept and is the same for everyone regardless of their location or perspective. It is a fundamental property of the universe.

5. How does the arrow of time relate to the beginning of the universe?

The arrow of time is closely related to the concept of the Big Bang and the beginning of the universe. The Big Bang is considered to be the starting point of time and since then, the arrow of time has been moving forward as the universe expands and evolves.

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