Why Does Cosmic Expansion End?

In summary, the article "The End of Cosmic Growth" discusses the future behavior of cosmic growth under both general relativity and modified gravity during prolonged acceleration. It suggests that gravity generally loses and growth ends, and that the "why now" problem is equally striking when viewed in terms of the shut down of growth. The article also notes that while f(R) models depart from GR in the present, their growth indices are identical in the asymptotic future and past. The conversation then discusses the anthropic principle as a potential explanation for why we live in a privileged time.
  • #1
wolram
Gold Member
Dearly Missed
4,446
558
Why do we live in such a privileged time?

arXiv:1810.10547 [pdf, ps, other]
The End of Cosmic Growth
Eric V. Linder, David Polarski
Comments: 5 pages, 6 figures
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

The growth of large scale structure is a battle between gravitational attraction and cosmic acceleration. We investigate the future behavior of cosmic growth under both general relativity (GR) and modified gravity during prolonged acceleration, deriving analytic asymptotic behaviors and showing that gravity generally loses and growth ends. We also note the `why now' problem is equally striking when viewed in terms of the shut down of growth. For many models inside GR the gravitational growth index γ also shows today as a unique time between constant behavior in the past and a higher asymptotic value in the future. Interestingly, while f(R) models depart in this respect dramatically from GR today and in the recent past, their growth indices are identical in the asymptotic future and past.
 
Space news on Phys.org
  • #2
I think that the title of this thread is misleading the article

wolram said:
arXiv:1810.10547 [pdf, ps, other]
The End of Cosmic Growth
Eric V. Linder, David Polarski
Comments: 5 pages, 6 figures
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO)

is not about the of expansion of the universe, it is about the end of growth of structures in the universe. Very roughly, the proper distance between structures is accelerating, not slowing down, but growth rate of the structures themselves will slow down (in many models).
 
  • #3
wolram said:
Why do we live in such a privileged time?

There may be a more satisfying answer than the anthropic principle, but that certainly applies. You definitely won't catch fish if your cast doesn't land in water.
 

1. Will the end of cosmic expansion result in the end of the universe?

While it is commonly believed that the end of cosmic expansion will lead to the end of the universe, this is not necessarily the case. The end of cosmic expansion simply refers to the point at which the expansion of the universe stops and begins to contract. The fate of the universe after this point is still uncertain and depends on various factors such as the amount of matter and energy in the universe.

2. How will the end of cosmic expansion affect the galaxies and stars?

The end of cosmic expansion will have a significant impact on the galaxies and stars in the universe. As the expansion stops and the universe begins to contract, the galaxies and stars will be pulled closer together. This could potentially lead to collisions between galaxies and the formation of new stars.

3. Can we predict when the end of cosmic expansion will occur?

At this time, it is not possible to accurately predict when the end of cosmic expansion will occur. The rate of expansion is influenced by various factors, such as the amount of dark energy in the universe, which are still not fully understood. Scientists continue to study and gather data in order to better understand the timeline of cosmic expansion.

4. What will happen to the expansion of space-time during the end of cosmic expansion?

The expansion of space-time, also known as the fabric of the universe, will also come to an end during the end of cosmic expansion. As the universe begins to contract, the space-time fabric will also start to shrink. This will eventually lead to the collapse of the universe.

5. Is the end of cosmic expansion a natural process?

The end of cosmic expansion is a natural process that is driven by the force of gravity. As the universe expands, the gravitational pull between objects becomes weaker. Eventually, this pull will become strong enough to overcome the expansion and cause the universe to contract. This is a fundamental process that is necessary for the cyclical nature of the universe.

Similar threads

A Black hole mass coupled to expansion -- astrophysical source of dark energy?
    • Cosmology
4
Replies
134
Views
6K
B Does dark energy or cosmic inflation explain flatness?
    • Cosmology
2
Replies
37
Views
3K
I Some questions about Cosmic Microwave Background radiation
    • Cosmology
Replies
13
Views
2K
I Some questions about Cosmic Inflation
    • Cosmology
Replies
4
Views
1K
B Why doesn't cosmic inflation violate conservation of energy?
    • Cosmology
Replies
3
Views
2K
B Hip Replacements and Weather Sensitivity
    • Cosmology
Replies
6
Views
1K
I Contraction prior to expansion?
    • Cosmology
Replies
5
Views
1K
I Cosmic Censorship: Does it Hold?
    • Special and General Relativity
Replies
2
Views
855
Is the Decaying Vacuum Model a Complete Description of Cosmic Expansion?
    • Cosmology
Replies
1
Views
2K
What is the key equation for distance growth in Kindercosmos?
    • Cosmology
Replies
12
Views
1K

Hot Threads

Recent Insights

Back
Top