Dark energy and expansion of space

Click For Summary

Discussion Overview

The discussion revolves around the concepts of dark energy and the expansion of the universe, particularly focusing on the implications of dark energy's behavior as the universe expands. Participants explore theoretical aspects, assumptions, and potential evidence regarding the constancy of dark energy density over time.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants assert that the universe is expanding since the Big Bang, leading to the conclusion that space is expanding, while others challenge this notion by suggesting that "space is expanding" is not an accurate description.
  • There is a proposal that dark energy is being created as bound systems move farther apart, with the density of dark energy remaining constant.
  • A participant questions the lack of experimental evidence supporting the idea that dark energy density is constant over time, suggesting it may be an assumption rather than a fact.
  • Concerns are raised about whether the average dark energy density could be inversely proportional to the total volume, implying that the total dark energy content might not be constant.
  • One participant references their understanding of dark energy as being based on discussions from knowledgeable individuals in the forum, rather than empirical studies.

Areas of Agreement / Disagreement

Participants express differing views on the nature of space expansion and the behavior of dark energy, indicating that multiple competing perspectives remain without a clear consensus.

Contextual Notes

There are limitations regarding the assumptions made about dark energy density and its constancy, as well as the lack of direct experimental evidence cited by participants. The discussion also highlights the dependence on definitions related to space and metric expansion.

kodama
Messages
1,090
Reaction score
144
universe is expanding since the bigbang so therefore space is expanding, but apparently dark energy remains constant, it apparently isn't getting diluted as the universe expands

is energy being created, specifically the energy in vacuum?
 
Physics news on Phys.org
kodama said:
universe is expanding since the bigbang so therefore space is expanding, but apparently dark energy remains constant, it apparently isn't getting diluted as the universe expands

is energy being created, specifically the energy in vacuum?
"Space is expanding" is not correct. Google "metric expansion" for a discussion.

Yes, dark energy is being created as bound systems get farther apart from each other. The density of dark energy remains the same.
 
phinds said:
Yes, dark energy is being created as bound systems get farther apart from each other. The density of dark energy remains the same.

Hm, do you know of any experimental evidence that dark energy density is constant in time, or is this just an assumption? Specifically, do you have any reason to believe that the average dark energy density is not inversely proportional to the "total volume"; i.e. that the "total dark energy content" is not constant after all?
 
Last edited:
no-ir said:
Hm, do you know of any experimental evidence that dark energy density is constant in time, or is this just an assumption? Specifically, do you have any reason to believe that the average dark energy density is not inversely proportional to the "total volume"; i.e. that the "total dark energy content" is not constant after all?
My references are all just other posts (by knowledgeable people) here on this forum. It is not an assumption, it is taken as empirically-based fact but I can't point you to a study saying so. I don't mean to imply that there aren't any, just that I don't have a citation for you.
 
phinds said:
"Space is expanding" is not correct.
What do you mean by this? Isn't spacetime defined by a manifold with a metric on it? :)
 
haushofer said:
What do you mean by this? Isn't spacetime defined by a manifold with a metric on it? :)
Google "metric expansion"
 

Similar threads

Graduate Discussion of "Two-Time Physics" (I. Bars) and its potential cosmological implications
  • · Replies 1 ·
Replies
1
Views
2K
Graduate "The 7 Strangest Coincidences in the Laws of Nature" (S. Hossenfelder)
  • · Replies 62 ·
3
Replies
62
Views
12K
Undergrad Questioning the timescape model
  • · Replies 27 ·
Replies
27
Views
2K
Undergrad Does dark-energy require a source of energy?
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad Dark energy is intrinsic to the space itself
  • · Replies 5 ·
Replies
5
Views
2K
High School Dark energy might not be constant after all
  • · Replies 8 ·
Replies
8
Views
5K
Undergrad Is suppressed gravitational pull a possible explanation for dark energy?
  • · Replies 10 ·
Replies
10
Views
3K
Graduate Can the huge energy of quantum vacuum explain the observed value of dark energy?
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Sachs-Wolfe effect in a Dark Energy universe?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Dark Matter , Dark energy and the Dirac equation
  • · Replies 3 ·
Replies
3
Views
2K