Dark energy and oscillating universe?

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Discussion Overview

The discussion revolves around the concept of dark energy and its implications for an oscillating universe model, specifically examining the calculations related to gravitational forces and harmonic oscillators. Participants explore theoretical frameworks regarding the universe's potential oscillation between a big bang and a big crunch, as well as the dynamics of stellar matter in such scenarios.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant calculates the gravitational force between two spherical regions of dark energy and proposes that the universe oscillates with a frequency of 10^ -19 s^-1 based on their calculations.
  • Another participant comments on the long time frame required to experimentally verify the initial calculations presented.
  • A participant challenges the feasibility of a big crunch scenario, arguing that gravitational effects would lead to deviations from straight-line trajectories, preventing a simple collapse back to a central point.
  • Another participant agrees with the critique of the big crunch model, suggesting that at the end of cosmic expansion, only dark matter and dark energy would remain, which would interact differently than stellar matter.
  • One participant speculates that dark matter would absorb dark energy, leading to a reunion of the two, setting the stage for a new big bang.

Areas of Agreement / Disagreement

Participants express disagreement regarding the viability of the big crunch scenario and the behavior of stellar matter during cosmic contraction. There is no consensus on the calculations or the implications of dark energy in relation to the oscillating universe model.

Contextual Notes

Participants' arguments depend on various assumptions about the nature of dark energy and dark matter, as well as the dynamics of cosmic expansion and contraction. The discussion does not resolve the mathematical validity of the initial calculations or the theoretical models proposed.

kurious
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If I take two spherical regions of space about one metre in radius,
they would contain about 10 ^ - 27 kg of dark energy each.
If I now say that the centres of these regions are one metre apart,
and assume that there is rest mass associated with dark energy (this rest mass being uniformly distributed in each of the spherical regions),
then using Force = G m1 m2 / r^ 2 I would get a force of attraction
for the spheres of 10^ -11 x 10^ -27 x 10^ - 27 / 1 x1 = 10^ -65 Newtons.

If these two spherical regions obeyed Hooke's law F = - constant x extension
then 10^ - 65 = k x 1 (I am assuming that earlier in the universe when it was smaller the centres of the spheres converged and at equilibrium there was no distance between them)
k = 10^ -65
Let's postulate that the universe oscillates regularly between a big bang and a big crunch.

The frequency of a harmonic oscillator is given by:

w = ( k/m)^1/2

w = ( 10^ -65 / 10^ -27) ^ 1/2

w = 10^ -19 s^-1.

So the universe would oscillate once every 10^ 19 seconds.
Is my calculation a valid calculation?
 
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Experimentally, it will take over 300 billions years to verify your calculation.
 
kurious said:
If I take two spherical regions of space about one metre in radius,
they would contain about 10 ^ - 27 kg of dark energy each.
If I now say that the centres of these regions are one metre apart,
and assume that there is rest mass associated with dark energy (this rest mass being uniformly distributed in each of the spherical regions),
then using Force = G m1 m2 / r^ 2 I would get a force of attraction
for the spheres of 10^ -11 x 10^ -27 x 10^ - 27 / 1 x1 = 10^ -65 Newtons.

If these two spherical regions obeyed Hooke's law F = - constant x extension
then 10^ - 65 = k x 1 (I am assuming that earlier in the universe when it was smaller the centres of the spheres converged and at equilibrium there was no distance between them)
k = 10^ -65
Let's postulate that the universe oscillates regularly between a big bang and a big crunch.

The frequency of a harmonic oscillator is given by:

w = ( k/m)^1/2

w = ( 10^ -65 / 10^ -27) ^ 1/2

w = 10^ -19 s^-1.

So the universe would oscillate once every 10^ 19 seconds.
Is my calculation a valid calculation?

I don't kow about your calculations but your Big Crunch physics has a problem. Using Hubble logic the stellar matter is supposed to reverse direction and head back to the center of it all, compress as pre-Big Bang and let 'er rip once more, right?

It can't happen anything like that. Even if there was a total reversal of expanding stellar matter in straight lines back to the center point, there will come a time when gravity effects start pulling the stellar matter together at huge velocities that would impart large deviations from the straight line trajectories. Slingshots like you've never seen! Nothing would crunch, it would just redistribute in the universe.
I'd rather watch Mayberry reruns.
 
geistkiesel is right!

geistkiesel said:
I don't kow about your calculations but your Big Crunch physics has a problem. Using Hubble logic the stellar matter is supposed to reverse direction and head back to the center of it all, compress as pre-Big Bang and let 'er rip once more, right?

It can't happen anything like that. Even if there was a total reversal of expanding stellar matter in straight lines back to the center point, there will come a time when gravity effects start pulling the stellar matter together at huge velocities that would impart large deviations from the straight line trajectories. Slingshots like you've never seen! Nothing would crunch, it would just redistribute in the universe.
I'd rather watch Mayberry reruns.

I agree with everything you said. At the end of cosmic expansion, there will be no stellar mass around to reverse direction. At that stage, there will only be dark matter and dark energy. The dark matter will contract and eventually begin sucking up all of that dark energy like a big sponge until DM and DE are reunited as one. Then and only then will the cycle be complete and ripe for the next BB.

I think I'll go watch Andy now.
 

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