What is the acceleration of the expansion of the Universe?

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Discussion Overview

The discussion revolves around the acceleration of the expansion of the universe, specifically seeking values for the acceleration and the rate of change of acceleration. Participants explore the implications of these values for theoretical models, including one that aims to supersede dark energy and propose a closed universe.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • Some participants express difficulty in finding specific values for the acceleration and rate of change of acceleration of the universe's expansion, indicating a need for these values in their theoretical work.
  • One participant mentions that the universe's expansion is known to be accelerating, but questions whether this acceleration is constant.
  • Another participant provides a velocity value (73.5 km/sec/Mpc) related to the expansion but clarifies that this is not the same as acceleration or the rate of change of acceleration.
  • There is a contention regarding the interpretation of the question, with some participants suggesting that the original poster may not have understood the existing information or that the values they seek may not exist.
  • A later reply emphasizes the distinction between the rate of expansion and the rate of change of expansion, suggesting that the latter may not be readily available in existing literature.
  • One participant asserts that the discussion of personal theories is off-topic for the forum, leading to the closure of the thread.

Areas of Agreement / Disagreement

Participants generally agree on the acceleration of the universe's expansion but disagree on the availability and interpretation of specific values related to acceleration and its rate of change. The discussion remains unresolved regarding the existence of the values sought.

Contextual Notes

Limitations include the potential misunderstanding of terms related to acceleration and expansion, as well as the lack of consensus on whether the values being sought are defined or available in current literature.

JamesGarderiner
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TL;DR
I am aware that the universe expansion is accelerating and I have heard that the acceleration might not be constant. I need values of the acceleration and rate of change of acceleration and I can't find any.
I can't find any values of acceleration or rate of change of acceleration of the expansion of the universe when I looked it up and I need these values for a theory I'm working on that could supersede dark energy and show the universe is closed even if everything accelorating away from us and even if the rate of change of acceleration is positive. Does anybody know these values or know where I might be able to find them? Thanks :)
 
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JamesGarderiner said:
Summary:: I am aware that the universe expansion is accelerating and I have heard that the acceleration might not be constant. I need values of the acceleration and rate of change of acceleration and I can't find any.

Does anybody know these values or know where I might be able to find them?
https://en.wikipedia.org/wiki/Expansion_of_the_universe
 
JamesGarderiner said:
Summary:: I am aware that the universe expansion is accelerating and I have heard that the acceleration might not be constant. I need values of the acceleration and rate of change of acceleration and I can't find any.

I can't find any values of acceleration or rate of change of acceleration of the expansion of the universe when I looked it up and I need these values for a theory I'm working on that could supersede dark energy and show the universe is closed even if everything accelorating away from us and even if the rate of change of acceleration is positive. Does anybody know these values or know where I might be able to find them? Thanks :)
What it means for the universe expansion to be accelerating is explained here:

https://blackwells.co.uk/bookshop/p...ology-by-Andrew-R-Liddle-author/9781118502143

A bargain at £24.99.
 
JamesGarderiner said:
I can't find any values of acceleration or rate of change of acceleration of the expansion of the universe
I can only conclude that either you didn't look very hard at all or you somehow didn't understand the answer when it was presented. This is what I got with a simple search
1631723048437.png
 
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phinds said:
I can only conclude that either you didn't look very hard at all or you somehow didn't understand the answer when it was presented. This is what I got with a simple search
73.5 km/sec/Mpc shows how the velocity of bodies relative to us changes with distance, If a star was 1 Mpc away from us it would be going 73.5 km/s. That's velocity, not acceleration nor rate of change of acceleration. How dare you slander me sir! If you were to read the question that the answer is for, it says the rate of expansion, not the rate of change of expansion, which is what you searched. That's why I'm having difficulty. Everywhere says the rate of expansion but non say the rate of change of expansion!
 
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PeroK said:
What it means for the universe expansion to be accelerating is explained here
I know what it means for the universe expansion to be accelerating, however, I can't find a magnitude of this acceleration. That's what I meant by the question.
 
JamesGarderiner said:
73.5 km/sec/Mpc shows how the velocity of bodies relative to us changes with distance, If a star was 1 Mpc away from us it would be going 73.5 km/s. That's velocity, not acceleration nor rate of change of acceleration. How dare you slander me sir! If you were to read the question that answer is for, it says the rate of expansion, not the rate of change of expansion, which is what you searched. That's why I'm having difficulty. Everywhere says the rate of expansion but non say the rate of change of expansion!
I didn't slander you, I offered two possibilities. You have shown that my second one was correct. You didn't understand the answer. You are looking for something that doesn't exist**. If it DID exist, the statement in Wikipedia would be incorrect and presumably would not be there (or in the hundreds, perhaps thousands, of other places you can find it, including textbooks.

@berkeman gave you a link in post #2 which explains the expansion.

**I'm assuming you mean rate of change of acceleration over time, in the sense that something a given distance D away from us is accelerating away from us now at rate X but that at some time in the future an object a distance D away from us will be accelerating away from us at a rate of nX and you are looking for n.
 
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JamesGarderiner said:
I need these values for a theory I'm working on
Discussion of personal theories is off topic for Physics Forums. Thread closed.
 

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