Can Light Escape the Boundaries of the Universe?

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Discussion Overview

The discussion centers around the concept of whether light can escape the boundaries of the universe, exploring theoretical implications of boundaries, the nature of light in a vacuum, and the geometry of the universe. It includes speculative reasoning about the universe's structure and the behavior of light within it.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question what prevents light from traveling beyond the universe's "boundaries," suggesting that if light can travel through a vacuum, it should be able to escape.
  • Others assert that current theories indicate the universe has no boundaries, which raises questions about the applicability of physical laws at such boundaries.
  • There is a suggestion that if light travels within the universe, it cannot escape, leading to further inquiries about the nature of vacuums and whether they exist in the universe.
  • Some participants reference the analogy of a balloon's surface to illustrate how something can grow without boundaries, while questioning if this implies a space for growth.
  • One participant proposes that a fourth dimension might be a consideration, but this does not necessarily mean light can traverse it.
  • A model is presented where a finite, boundaryless universe could curve back on itself, suggesting that light traveling in a straight line could return to its origin without encountering a boundary.

Areas of Agreement / Disagreement

Participants express differing views on the existence of boundaries in the universe and the implications for light's behavior. There is no consensus on whether light can escape or what the nature of the universe's boundaries might be.

Contextual Notes

Limitations include assumptions about the nature of vacuums, the applicability of current physical laws at potential boundaries, and the speculative nature of higher dimensions in relation to light's travel.

madphysics
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If light can travel through a vacuum, what's to keep it from traveling out of the "boundaries" of the universe?

If it can, Why doesn't it?

If it can't, what is out their must be something other than a vacuum, or the light can't travel in a vacuum.




Right?
 
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According to present theory, the universe has no boundaries.
 
We don't really know about the boundaries of the universe, or if there are or are not boundaries, or if the physical laws as we understand them even apply at the boundaries.
 
If light travels there, it is in our universe.
 
But still, what keeps light from "escaping" our universe? Is it the fact that their is no true vacuum in which we can prove light does travel?
 
mathman said:
According to present theory, the universe has no boundaries.

Really?

I was under the immpresion that for something to grow in size, it had to have prevu=iuos boundaries to grow past.
 
madphysics said:
Really?

I was under the immpresion that for something to grow in size, it had to have prevu=iuos boundaries to grow past.


The usual picture is the two dimensional analog, the surface of a balloon, which can get bigger with no boundary.
 
Wouldn't that still imply something to grow into?
 
It likely would, yes. One example is a fourth dimension. But that doesn't mean light can travel through it.


The easiest way to think about a finite boundaryless universe is to think of it curving back on itself in 3D, like the balloon does in 2D. If a light beam heads in a straight line long enough, it simply arrives back at its starting point. It has not left our universe, nor has it encountered any sort of boundary.
 
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