Thought experiment: Communication beyond the particle horizon

In summary, the conversation discusses the concept of using white and pink nodes to broadcast signals at light speed and how their respective particle horizons allow for communication between them. The question asks if the starting and ending nodes can exchange information in a finite amount of time while maintaining their relative distances. The answer is yes, but it is important to note that the particle horizons must be within each other's cosmological horizons to communicate and the nodes will be receding from each other at a rate exceeding the speed of light.
  • #1
Lanniakea
14
1
Refer to this image: http://imgur.com/xT20HOv

  1. The white nodes are 'stations' which broadcast signals at light speed. The blue circles around them represent the particle horizon relative to these nodes.
  2. The pink nodes are intermediary stations in between these stations that pass on the signal. The pink circles are their respective particle horizons.
  3. All nodes always maintain the same distance relative to each other; they move in a way to negate the expansion of the universe.
  4. The number of nodes in the example is arbitrary.
The idea:

A signal is sent from the starting node and reaches the first pink node. From here it is sent toward the next white 'station' node. Now here's the idea: Even though the signal has left the particle horizon of the starting node, the next station's particle horizon includes both white nodes. So while the two white nodes cannot communicate directly, the pink node is in reach for both of them.

The Question: Could the starting and ending node exchange information in a finite amount of time, given that the nodes maintain their relative distances?

Thanks!
 
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  • #2
Lanniakea said:
The Question: Could the starting and ending node exchange information in a finite amount of time, given that the nodes maintain their relative distances?
Yes. Particle horizons grow without limit as time goes on. See the Davis expansion graphs: https://www.physicsforums.com/attachments/davisdiagramoriginal2-jpg.55869/

But take note that if your circles are of particle horizon sizes, they are much larger than the Hubble radius and they cannot "hold station", but will instead be receding from each other at a rate exceeding c. Also, they must be within each others cosmological (communications) horizons to ever communicate.
 
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Related to Thought experiment: Communication beyond the particle horizon

1. What is a thought experiment?

A thought experiment is a mental exercise or hypothetical scenario used to explore a concept or idea. It allows scientists to test theories or ideas in a controlled environment without the need for physical experimentation.

2. What is the particle horizon?

The particle horizon is the maximum distance from which particles or signals can have reached us since the beginning of the universe. It is currently estimated to be around 46 billion light-years away, as the universe is approximately 13.8 billion years old.

3. How is communication beyond the particle horizon possible in a thought experiment?

In a thought experiment, we can imagine scenarios where particles or signals can travel faster than the speed of light, allowing for communication beyond the particle horizon. This is not possible in reality according to the laws of physics, but it allows scientists to explore the potential implications and consequences of such scenarios.

4. What are some potential implications of communication beyond the particle horizon?

If communication beyond the particle horizon were possible, it would have significant implications on our understanding of the laws of physics and the nature of the universe. It could also potentially lead to new technologies and ways of communication that are currently unimaginable.

5. Are there any real-world applications for this thought experiment?

While the concept of communication beyond the particle horizon is purely hypothetical and not currently possible, the thought experiment itself can be used to expand our knowledge and understanding of the universe and its laws. It also allows for creative and critical thinking, which can be applied to various fields of science and technology.

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