Cosmology Forum

Post thread
Join in expert discussion on topics revolving around cosmology. Cosmology is the origin, evolution, structure and eventual fate of the universe.
  • Sticky
Insights Intro to Big Bang and Infinity Concepts - Comments
  • · Replies 62 ·
3
Replies
62
Views
18K
  • Sticky
Insights Equations of State for Photon Gas and Relativistic Electron Gas
  • · Replies 0 ·
Replies
0
Views
6K
  • Sticky
Insights A Journey Into the Cosmos - FLRW Metric and The Friedmann Equation - Comments
  • · Replies 0 ·
Replies
0
Views
7K
I The quintessence as variable dark energy
  • · Replies 18 ·
Replies
18
Views
1K
A Couldn't the cosmological constant also have some sort of "dynamics"?
  • · Replies 4 ·
Replies
4
Views
462
B Red shifted tired light doubts
  • · Replies 10 ·
Replies
10
Views
1K
A Strong Progenitor Age Bias in Supernova Cosmology
  • · Replies 30 ·
2
Replies
30
Views
3K
B If the Universe has a cause, what caused that cause?
  • · Replies 13 ·
Replies
13
Views
2K
B Looking to get a better understanding of bubble universe formation
  • · Replies 3 ·
Replies
3
Views
750
B Rutgers finds a transparent Einstein Cross - apparently a dark matter "halo"
  • · Replies 8 ·
Replies
8
Views
1K
I Before the Big Bang
  • · Replies 24 ·
Replies
24
Views
780
I Questions about quantum cosmology
  • · Replies 8 ·
Replies
8
Views
522
I Where did the early photons go?
  • · Replies 36 ·
2
Replies
36
Views
965
B Can big bang be a part of a loop?
  • · Replies 2 ·
Replies
2
Views
315
I Are primordial fluctuations the source of all structure?
  • · Replies 5 ·
Replies
5
Views
397
B What happens to information inside a blackhole
  • · Replies 4 ·
Replies
4
Views
381
I Illuminating Black Hole Shadows with Dark Matter Annihilation
  • · Replies 5 ·
Replies
5
Views
512
B Matter density right after the decoupling
  • · Replies 13 ·
Replies
13
Views
723
B Inflation after Atacama Cosmology Telescope Results
  • · Replies 3 ·
Replies
3
Views
568
B Realism about singularity
  • · Replies 38 ·
2
Replies
38
Views
857
I Cosmological perturbations and CMBR anisotropies
  • · Replies 3 ·
Replies
3
Views
484
B What is conformal time?
  • · Replies 10 ·
Replies
10
Views
615
B Cosmic Microwave Background Stage 4 Cancelled for now
  • · Replies 4 ·
Replies
4
Views
651
I Is Introducing a New Cosmological Model Based on Aether Theory Permissible Here?
  • · Replies 1 ·
Replies
1
Views
1K
I No symmetries in the Universe at the Big Bang...?
  • · Replies 12 ·
Replies
12
Views
3K
B Flatlander analogy of spherical surface as observable universe
  • · Replies 6 ·
Replies
6
Views
893
B Conflict between the conservation of matter and the rapid expansion of our universe
  • · Replies 18 ·
Replies
18
Views
1K
I The impact of early galaxy formation on the CMBR
  • · Replies 20 ·
Replies
20
Views
2K
I Age of the Universe and the Cosmological Constant
  • · Replies 17 ·
Replies
17
Views
2K
I Hubble Constant, Dark Energy and the Expanding Universe
  • · Replies 15 ·
Replies
15
Views
4K
B Big Bang and Infinite Universe
  • · Replies 20 ·
Replies
20
Views
1K
I How to calculate the mass within the Hubble Sphere?
  • · Replies 3 ·
Replies
3
Views
937
A Hubble tension -- any resolution?
  • · Replies 94 ·
4
Replies
94
Views
9K
B Can You Ace Harvard's Galactic Quiz?
  • · Replies 27 ·
Replies
27
Views
2K
I Dark Matter , Dark energy and the Dirac equation
  • · Replies 3 ·
Replies
3
Views
1K
I Cosmological Redshift and Expansion
  • · Replies 20 ·
Replies
20
Views
2K
B Could Black Hole Collisions Trigger a Cyclical Big Bang and Universe Rebirth?
  • · Replies 19 ·
Replies
19
Views
2K
B Thought experiment to compare the present with the future flow of time
  • · Replies 7 ·
Replies
7
Views
1K
B Proper time of the observer resting in CMB reference frame
  • · Replies 70 ·
3
Replies
70
Views
3K
I How do you get to the conclusion that there is accelerating expansion?
  • · Replies 23 ·
Replies
23
Views
3K
I Inflation Models that don't produce Multiverse?
  • · Replies 5 ·
Replies
5
Views
1K
B What Would You See at the Edge of the Expanding Universe?
  • · Replies 17 ·
Replies
17
Views
2K
B Does an infinite universe contradict a Big Bang origin?
  • · Replies 65 ·
3
Replies
65
Views
7K
I Is the amount of dark matter constant in the Universe?
  • · Replies 20 ·
Replies
20
Views
3K
I If white holes were to exist in our Universe
  • · Replies 30 ·
2
Replies
30
Views
3K
A Black Hole TON618 - Wavelength Spectrum
  • · Replies 38 ·
2
Replies
38
Views
4K
A Late time and early time approximation for EOS
  • · Replies 0 ·
Replies
0
Views
1K
I Will DESI confirm that the Universe isn't described by the ΛCDM model?
  • · Replies 18 ·
Replies
18
Views
3K
B Estimates — True Size of the Universe?
  • · Replies 17 ·
Replies
17
Views
4K
I Questions on the consequence of an evolving dark energy parameter
  • · Replies 1 ·
Replies
1
Views
2K
B Dark Matter Theory Endorsed By NASA
  • · Replies 4 ·
Replies
4
Views
1K
I Resolution of Peeble's ODE equation
  • · Replies 1 ·
Replies
1
Views
1K
B An old spin to our Universe
  • · Replies 4 ·
Replies
4
Views
2K
  • Featured
I Early large galaxy studies
  • · Replies 10 ·
Replies
10
Views
5K
I Question about Tong's cosmology lecture notes eqn. 1.19
  • · Replies 7 ·
Replies
7
Views
2K
A What does it mean to model the distribution of galaxies as cosmic dust?
  • · Replies 6 ·
Replies
6
Views
3K
B How do we know if a distant galaxy is matter or anti-matter?
  • · Replies 11 ·
Replies
11
Views
2K
B Questions about the Eddington Limit and Super - Eddington black holes
  • · Replies 0 ·
Replies
0
Views
2K
A Models without dark energy
  • · Replies 29 ·
Replies
29
Views
3K
A Is there a stretching of the light curves of supernovae 1a?
  • · Replies 5 ·
Replies
5
Views
2K
I 3 questions about a paper on density fluctuations in the Universe
  • · Replies 1 ·
Replies
1
Views
2K
B Evolution of the Universe in reverse
  • · Replies 41 ·
2
Replies
41
Views
4K
A Interpretation of an anticorrelation between 𝐻0 and log10(𝜔𝐵𝐷)
  • · Replies 1 ·
Replies
1
Views
3K
I The Boundary of the Observable Universe
  • · Replies 44 ·
2
Replies
44
Views
5K
I Do particles leave behind an image when crossing cosmo event horizon?
  • · Replies 14 ·
Replies
14
Views
3K
I How would the laws of thermodynamics change in a contracting universe?
  • · Replies 5 ·
Replies
5
Views
2K
B Cosmological Redshift in Simulated Universe
  • · Replies 39 ·
2
Replies
39
Views
6K
A Form of energy at time of big bang
  • · Replies 11 ·
Replies
11
Views
3K
I Why do we still see the CMB today?
  • · Replies 103 ·
4
Replies
103
Views
11K
A Black hole thermodynamics and accelerated expansion
  • · Replies 2 ·
Replies
2
Views
3K
I Two-dimensional negative curvature space
  • · Replies 2 ·
Replies
2
Views
2K
B Redshifts of nearby galaxies
  • · Replies 14 ·
Replies
14
Views
3K
I The Universe is expanding with acceleration
  • · Replies 5 ·
Replies
5
Views
3K
I Distance at redshift z=0.666
  • · Replies 37 ·
2
Replies
37
Views
5K
A Dark matter is running out of places to hide!
  • · Replies 17 ·
Replies
17
Views
3K
B Galactic Sheets and Voids
  • · Replies 14 ·
Replies
14
Views
2K
I Bose-Einstein and Fermionic condensates in space?
  • · Replies 13 ·
Replies
13
Views
3K
B How can an infinite universe expand?
  • · Replies 12 ·
Replies
12
Views
3K
I What if the early expansion of the Universe was not so rapid?
  • · Replies 12 ·
Replies
12
Views
3K
I Does the amount of hidden mass remain constant?
  • · Replies 2 ·
Replies
2
Views
2K
B Do Fictional Worlds Exist in the Multiverse?
  • · Replies 8 ·
Replies
8
Views
5K
B Questions about a paper on reconciling JWST and HST data
  • · Replies 4 ·
Replies
4
Views
3K
I How we are in a matter dominated universe (without antimatter annihilation)
  • · Replies 13 ·
Replies
13
Views
3K
I Toward the spectral index in slow roll
  • · Replies 1 ·
Replies
1
Views
3K
I Density fluctuations in a homogeneous linearly expanding universe?
  • · Replies 7 ·
Replies
7
Views
3K
I What is the reason for density perturbations in the CMB?
  • · Replies 1 ·
Replies
1
Views
2K
I Question on halos of matter made from massive and stable particles?
  • · Replies 53 ·
2
Replies
53
Views
6K
A Celestial objects - older than the CMB
  • · Replies 7 ·
Replies
7
Views
3K
B Big Bang as the Collapse of a Wave Function
  • · Replies 3 ·
Replies
3
Views
3K
B Expected Earth-relative velocity of interstellar particles
  • · Replies 7 ·
Replies
7
Views
3K
A HST measures Draco dwarf galaxy over 18 years in DM study
  • · Replies 1 ·
Replies
1
Views
3K
A Trying to plot a graph of energy densities for radiation and PBHs
  • · Replies 2 ·
Replies
2
Views
2K
I Diameter of the observable Universe
  • · Replies 13 ·
Replies
13
Views
3K
I Is Baryogenesis a Convincing Hypothesis?
  • · Replies 3 ·
Replies
3
Views
3K
I Could cosmic rays induce a vacuum decay in the future?
  • · Replies 5 ·
Replies
5
Views
3K
A Is the Jeffry Scale/Bayes Factor Still Used for Testing Inflationary Models?
  • · Replies 0 ·
Replies
0
Views
2K
B Approximately how long does it take for a galaxy to form?
  • · Replies 12 ·
Replies
12
Views
3K
B Discussion on the source or cause of Dark Energy Dark Matter et al
  • · Replies 6 ·
Replies
6
Views
3K
A Horndeski: denominator null implies an infinite quantity
  • · Replies 16 ·
Replies
16
Views
3K
I Hydrogen line observation frequency range and space Hydrogen speed?
  • · Replies 33 ·
2
Replies
33
Views
3K
I What temperature would 1 keV neutrinos have today?
  • · Replies 14 ·
Replies
14
Views
3K
I "Energy is not conserved" vs. energy is conserved: Friedmann Equations
  • · Replies 17 ·
Replies
17
Views
5K
I Questions about paper "How closed is cosmology"
  • · Replies 18 ·
Replies
18
Views
4K