Could Dark Energy lead to a big bang?

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Discussion Overview

The discussion revolves around the concept of dark energy and its potential implications for the universe's expansion and the cyclical nature of cosmic evolution. Participants explore the relationship between dark energy, virtual particles, and the fate of the universe, including scenarios involving heat death and inflation.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant proposes that the universe could be cyclical and infinite, suggesting that dark energy's role in accelerating expansion might eventually lead to a scenario where virtual particles cannot annihilate each other, potentially triggering a new cosmic evolution.
  • Another participant counters that dark energy does not cause the universe to expand faster and faster, indicating that the simplest models suggest a gradual slowing of the expansion rate to a constant value.
  • There is a clarification regarding the nature of accelerated expansion, where one participant notes that while the universe is accelerating, the expansion at the scale of virtual particles may be different.
  • One participant expresses confusion about the relationship between the expansion of the universe and virtual particles, indicating a need for further clarification on the topic.
  • Another participant asserts that virtual particles are not relevant to the discussion of cosmic expansion rates.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the implications of dark energy on the universe's expansion and the role of virtual particles. There is no consensus on whether dark energy could lead to a cyclical universe or how it interacts with virtual particles.

Contextual Notes

Some assumptions about the nature of dark energy and its effects on cosmic expansion remain unresolved. The discussion reflects varying interpretations of the relationship between expansion rates and virtual particles.

newjerseyrunner
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I had a thought a while ago, but it was removed because I cited a youtube video of physicists talking rather than papers, so I'll have another go.

My thought was that the universe could be cyclical and infinite even if heat death is the eventual end of the universe as we know it. During the big bang, inflation could have caused virtual particles to not be able to annihilate each other because space expanded faster than light (Hawking radiation.)

The universe is known to be expanding and accelerating because of dark energy. When calculating all of the known forces out (fully aware that our understanding of the universe is incomplete,) we determine that the universe should die of heat death with entropy increasing to the maximum and space expanding forever.

So that brings me to my question: if dark energy causes the universe to expand faster and faster, eventually, shouldn't it get to such a degree that it's expanding faster than light again? It this point, wouldn't the virtual particles that are constantly created and destroy be unable to destroy each other and suddenly fill the universe with gamma rays and basically start the whole of cosmic evolution again?
 
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As far as we know, dark energy doesn't cause the universe to expand faster and faster. The rate of expansion is still slowing down, and the simplest models have the rate of expansion gradually slowing to a constant value (given by the cosmological constant).

This is called an accelerated expansion because if the expansion rate is constant, then things get faster as they get further away from one another, so that objects within the universe are accelerating away from one another.
 
Oh ok, so the universe is accelerating because of scale, but the expansion at the scale of virtual particles, it's actually slowing? I didn't know that, thanks.
 
newjerseyrunner said:
Oh ok, so the universe is accelerating because of scale, but the expansion at the scale of virtual particles, it's actually slowing? I didn't know that, thanks.
The rate of expansion is defined as velocity over distance. That is, at a given rate of expansion, a galaxy that is twice as far away is receding twice as fast. If that rate is a constant, then as things get further, they recede faster.

Virtual particles don't come into it.
 

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