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Cosmology Forum

Join in expert discussion on topics revolving around cosmology. Cosmology is the origin, evolution, structure and eventual fate of the universe.

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I How many apparent horizons could the Universe have?

Aug 19, 2022 · Replies 12 · Oct 26, 2022

Replies: 12

Views: 2K

I Sachs-Wolfe effect in a Dark Energy universe?

Oct 24, 2022 · Replies 1 · Oct 24, 2022

Replies: 1

Views: 2K

B Light element abundances for He3/H?

Oct 17, 2022 · Replies 1 · Oct 24, 2022

Replies: 1

Views: 1K

I Can there be some kind of photon emission caused by space expansion?

Oct 21, 2022 · Replies 4 · Oct 21, 2022

Replies: 4

Views: 1K

B Can physical constants be different in other galaxies?

Oct 16, 2022 · Replies 26 · Oct 20, 2022

Replies: 26

Views: 3K

B Gravitomagnetic explanation of Dark Matter

Oct 13, 2022 · Replies 7 · Oct 14, 2022

Replies: 7

Views: 2K

I Data Showing Dark Matter Is Not Cold Neutrinos?

Oct 10, 2022 · Replies 13 · Oct 10, 2022

Replies: 13

Views: 2K

I Cosmic Event Horizon – Does it have any real effects?

Sep 24, 2022 · Replies 9 · Oct 4, 2022

Replies: 9

Views: 3K

I Particle production in an expanding universe?

Sep 25, 2022 · Replies 6 · Sep 29, 2022

Replies: 6

Views: 2K

I Is energy conserved during the formation of local systems?

Sep 28, 2022 · Replies 2 · Sep 28, 2022

Replies: 2

Views: 2K

B Gas planets with solid satellites

Sep 25, 2022 · Replies 2 · Sep 25, 2022

Replies: 2

Views: 1K

B Expansion of Space Itself, rather than due to an Explosion like the Big Bang?

Sep 12, 2022 · Replies 9 · Sep 24, 2022

Replies: 9

Views: 3K

B What is the recession speed today of the matter which created the CMBR?

Aug 30, 2022 · Replies 57 · Sep 17, 2022

2

Replies: 57

Views: 5K

I Cosmic Flatness Deduced from CMB

Sep 9, 2022 · Replies 4 · Sep 12, 2022

Replies: 4

Views: 2K

I Relationship between geometry and expansion rate

Sep 9, 2022 · Replies 7 · Sep 12, 2022

Replies: 7

Views: 2K

B Bound Systems in an Expanding Universe: How Can Galaxies Merge?

Sep 5, 2022 · Replies 9 · Sep 7, 2022

Replies: 9

Views: 2K

I LightCone Calculator Improvements

Jul 21, 2022 · Replies 100 · Sep 4, 2022

4

Replies: 100

Views: 7K

A Cosmic Tidal Force: Measuring CTF With Strain Gauge

Aug 28, 2022 · Replies 61 · Sep 1, 2022

3

Replies: 61

Views: 5K

A Multiverse and observational evidence?

Aug 29, 2022 · Replies 10 · Aug 29, 2022

Replies: 10

Views: 3K

I Mining the Universe's expansion?

Aug 24, 2022 · Replies 25 · Aug 26, 2022

Replies: 25

Views: 3K

On the origin and the evolution of information in the Universe

Aug 24, 2022 · Replies 1 · Aug 26, 2022

Replies: 1

Views: 2K

I Receding movement of a stopped object in an accelerating universe?

Aug 23, 2022 · Replies 23 · Aug 25, 2022

Replies: 23

Views: 2K

I Lectures on the Varying fine structure constant

Aug 12, 2022 · Replies 7 · Aug 24, 2022

Replies: 7

Views: 2K

I Cosmic strings increasing internal energy?

Aug 22, 2022 · Replies 1 · Aug 22, 2022

Replies: 1

Views: 2K

A Is the FLRW Metric a Valid Approximation for Our Universe on Large Scales?

Aug 4, 2022 · Replies 7 · Aug 13, 2022

Replies: 7

Views: 2K

A Non-minimally coupled inflation — expansion

Aug 12, 2022 · Replies 1 · Aug 12, 2022

Replies: 1

Views: 2K

B Understanding the Expansion of Space: Galaxies Moving Away and Proving Expansion

Oct 19, 2017 · Replies 78 · Aug 10, 2022

3

Replies: 78

Views: 9K

I How Does Space Expansion Affect the Velocity of Galaxies?

Jun 4, 2022 · Replies 65 · Aug 10, 2022

3

Replies: 65

Views: 6K

I Distant Galaxy study, dark matter and the CMBR

Aug 4, 2022 · Replies 1 · Aug 8, 2022

Replies: 1

Views: 2K

I What Equation Determines the Cosmic Event Horizon Distance?

Aug 6, 2022 · Replies 7 · Aug 6, 2022

Replies: 7

Views: 3K

B Could the source of dark energy be our parent black hole feeding?

Aug 4, 2022 · Replies 6 · Aug 5, 2022

Replies: 6

Views: 2K

I What is the significance of slow-roll inflation in cosmology?

Jul 29, 2022 · Replies 1 · Jul 30, 2022

Replies: 1

Views: 2K

I JWST breaks another Redshift record

Jul 30, 2022 · Replies 2 · Jul 30, 2022

Replies: 2

Views: 1K

B Could a Galaxy Older than 13.8 Billion Years Redefine Cosmology?

Jul 29, 2022 · Replies 4 · Jul 29, 2022

Replies: 4

Views: 2K

Is the Universe Finite, or Is It Infinite?

Jun 14, 2011 · Replies 27 · Jul 29, 2022

Replies: 27

Views: 12K

I Is the Bullet Cluster Evidence for or Against Dark Matter?

Jul 23, 2022 · Replies 7 · Jul 29, 2022

Replies: 7

Views: 4K

I A glitch in Jorrie’s Cosmo-Calculator?

Apr 30, 2022 · Replies 152 · Jul 23, 2022

6

Replies: 152

Views: 10K

I Paradox: How can we look back at the Big Bang?

Jul 14, 2022 · Replies 31 · Jul 22, 2022

2

Replies: 31

Views: 3K

I Question re flat infinite universe with a preferred direction

Jul 15, 2022 · Replies 5 · Jul 17, 2022

Replies: 5

Views: 2K

I Why is the observed local region of space flat?

Jul 13, 2022 · Replies 25 · Jul 14, 2022

Replies: 25

Views: 3K

I A new solution to Olbers' Paradox?

Apr 3, 2017 · Replies 20 · Jul 14, 2022

Replies: 20

Views: 4K

B Temporal differences across a galaxy?

Jul 13, 2022 · Replies 6 · Jul 13, 2022

Replies: 6

Views: 2K

I Reheating and the horizon problem - chicken and egg?

Jul 25, 2016 · Replies 6 · Jul 10, 2022

Replies: 6

Views: 3K

Can the Universe's Expansion Allow Us to Escape Its Event Horizon?

Dec 28, 2005 · Replies 1 · Jul 4, 2022

Replies: 1

Views: 4K

B Big Bang Question -- How was the first matter formed?

Mar 7, 2022 · Replies 69 · Jul 3, 2022

3

Replies: 69

Views: 6K

How are time and distance measured in cosmology?

Jun 14, 2011 · Replies 1 · Jul 2, 2022

Replies: 1

Views: 12K

What is the total mass-energy of the universe?

Jun 14, 2011 · Replies 1 · Jul 2, 2022

Replies: 1

Views: 19K

I The curvature of space and curvature of spacetime

Jun 30, 2022 · Replies 21 · Jul 1, 2022

Replies: 21

Views: 2K

I Bubble universes and physical constants

Jun 17, 2022 · Replies 8 · Jun 30, 2022

Replies: 8

Views: 3K

I Some questions about Cosmic Microwave Background radiation

Jun 22, 2022 · Replies 13 · Jun 28, 2022

Replies: 13

Views: 6K

I I have an error in integrating to calculate the age of the Universe

Jun 19, 2022 · Replies 40 · Jun 23, 2022

2

Replies: 40

Views: 4K

I How does the symbol Λ cosmological constant relate to Ω_Λ or ρ_Λ?

Jun 18, 2022 · Replies 3 · Jun 21, 2022

Replies: 3

Views: 2K

I Some questions about Cosmic Inflation

Jun 18, 2022 · Replies 4 · Jun 19, 2022

Replies: 4

Views: 4K

I Are there types of spacetime where no symmetries are valid?

May 20, 2022 · Replies 15 · Jun 16, 2022

Replies: 15

Views: 2K

I Seeking understanding regarding Ω_b, Ω_c, and Ω_m

Jun 13, 2022 · Replies 14 · Jun 16, 2022

Replies: 14

Views: 3K

B How much energy does our Universe have?

Jun 13, 2022 · Replies 12 · Jun 15, 2022

Replies: 12

Views: 2K

I Postulating a minimum gravitational field strength

Jun 5, 2022 · Replies 11 · Jun 15, 2022

Replies: 11

Views: 2K

I Questions about Negative Pressure and Vacuum Energy

Jun 13, 2022 · Replies 5 · Jun 13, 2022

Replies: 5

Views: 3K

I If the Universe had a different size, would physics change?

Jun 7, 2022 · Replies 15 · Jun 11, 2022

Replies: 15

Views: 2K

I Is the CPT-Symmetric Universe Theory the Key to Solving the Antimatter Mystery?

Jun 6, 2022 · Replies 1 · Jun 9, 2022

Replies: 1

Views: 2K

I Alexander Vilenkin and energy of a closed universe

Jun 6, 2022 · Replies 32 · Jun 8, 2022

2

Replies: 32

Views: 2K

I Seeking reference for math related to the age of Recombination

May 18, 2022 · Replies 3 · Jun 4, 2022

Replies: 3

Views: 2K

B Explaining Cosmic Inflation using analogies

May 17, 2022 · Replies 3 · May 18, 2022

Replies: 3

Views: 2K

A Understanding distances in Cosmology

May 11, 2022 · Replies 1 · May 18, 2022

Replies: 1

Views: 2K

I Will the upcoming experiment PICO measure kSZ temperature anisotropy?

May 12, 2022 · Replies 1 · May 17, 2022

Replies: 1

Views: 1K

I Looking for a chart showing various growths of the Universe

May 6, 2022 · Replies 14 · May 7, 2022

Replies: 14

Views: 2K

A Peebles Equation for fractional electron density

Apr 28, 2022 · Replies 7 · May 5, 2022

Replies: 7

Views: 2K

I What's the source of energy for the universe's expasion?

May 5, 2022 · Replies 5 · May 5, 2022

Replies: 5

Views: 1K

B How good are our ears? (Detectable Interstellar signals)

May 4, 2022 · Replies 7 · May 5, 2022

Replies: 7

Views: 2K

A Can Representing Ideas be Possible?

Apr 27, 2022 · Replies 8 · Apr 27, 2022

Replies: 8

Views: 2K

I Observations fit poorly with the Standard Model of Cosmology

Feb 14, 2022 · Replies 34 · Apr 25, 2022

2

Replies: 34

Views: 4K

I How is the sound horizon at recombination and BAO measured in the CMB?

Apr 10, 2022 · Replies 1 · Apr 22, 2022

Replies: 1

Views: 2K

I How far into the Universe can we theoretically reach?

Apr 3, 2022 · Replies 34 · Apr 20, 2022

2

Replies: 34

Views: 4K

I Is Entropy in the Universe Lower Now Than After the Big Bang Due to Heat?

Feb 13, 2022 · Replies 25 · Apr 18, 2022

Replies: 25

Views: 3K

I Varying laws of high energy physics in inflation?

Apr 15, 2022 · Replies 4 · Apr 15, 2022

Replies: 4

Views: 2K

I An odd result from integrating to calculate the age of the Universe

Apr 11, 2022 · Replies 21 · Apr 12, 2022

Replies: 21

Views: 2K

I Information lost at the Big Crunch?

Apr 10, 2022 · Replies 3 · Apr 10, 2022

Replies: 3

Views: 1K

I Questions about bayronic acoustic oscillations

Jun 6, 2019 · Replies 9 · Apr 9, 2022

Replies: 9

Views: 3K

A Questions: Gott-Li Can a Universe Create Itself?

Apr 3, 2022 · Replies 2 · Apr 4, 2022

Replies: 2

Views: 2K

B What is the oldest of each class of star?

Apr 2, 2022 · Replies 2 · Apr 2, 2022

Replies: 2

Views: 2K

B Experimental evidence on cosmological redshift

Mar 12, 2022 · Replies 34 · Mar 25, 2022

2

Replies: 34

Views: 4K

A Which galaxies have the best studied evidence for dark matter?

Mar 16, 2022 · Replies 4 · Mar 17, 2022

Replies: 4

Views: 2K

A Graceful exit of a cosmological inflation model

Feb 27, 2022 · Replies 3 · Mar 13, 2022

Replies: 3

Views: 2K

I What does the equation dΩ32 = dr2 + r2dΩ22 mean in terms of flat space?

Mar 4, 2022 · Replies 6 · Mar 7, 2022

Replies: 6

Views: 2K

B What Function Does Dark Matter or Energy Serve?

Feb 14, 2022 · Replies 13 · Mar 1, 2022

Replies: 13

Views: 2K

B For object 3.26 million light-years away, light redshifted by 70 km/s

Feb 24, 2022 · Replies 12 · Feb 27, 2022

Replies: 12

Views: 2K

A Numerically solving Scalar field coupled to Friedman equation

Feb 16, 2022 · Replies 3 · Feb 22, 2022

Replies: 3

Views: 2K

B How could something that is infinite (the Universe) expand?

Feb 20, 2022 · Replies 30 · Feb 21, 2022

2

Replies: 30

Views: 3K

B What does the Universe exapand into?

Feb 12, 2022 · Replies 27 · Feb 17, 2022

Replies: 27

Views: 2K

I Calculating the probability that the Universe is finite

Jan 30, 2022 · Replies 70 · Feb 16, 2022

3

Replies: 70

Views: 4K

I What if the Universe expands faster than the speed of light?

Feb 2, 2022 · Replies 19 · Feb 13, 2022

Replies: 19

Views: 4K

B Basic confusion about the Big Bang and light cones

Feb 12, 2022 · Replies 11 · Feb 12, 2022

Replies: 11

Views: 2K

I Question about the Hubble Constant

Feb 10, 2022 · Replies 14 · Feb 11, 2022

Replies: 14

Views: 2K

B Question regarding light from distant objects

Jan 2, 2022 · Replies 8 · Feb 11, 2022

Replies: 8

Views: 2K

I An idea for calculating the probability that the Universe is flat

Feb 8, 2022 · Replies 20 · Feb 9, 2022

Replies: 20

Views: 2K

I Edwin Hubble and the Evidence for Universe Expansion

Jan 2, 2022 · Replies 49 · Feb 9, 2022

2

Replies: 49

Views: 5K

A What assumptions underlie the proof that singularities are inevitable?

Feb 7, 2022 · Replies 5 · Feb 8, 2022

Replies: 5

Views: 1K

A Relativistic Redshift and understanding it's approximation

Feb 7, 2022 · Replies 4 · Feb 7, 2022

Replies: 4

Views: 1K

A Peculiar Acceleration - Understanding an Equation

Feb 7, 2022 · Replies 3 · Feb 7, 2022

Replies: 3

Views: 995

I Does Dark Matter Have a Temperature?

Nov 22, 2021 · Replies 25 · Feb 3, 2022

Replies: 25

Views: 3K

Cosmology

Cosmology is the scientific study of the large-scale structure, origin, evolution, and ultimate fate of the universe. It seeks to understand the fundamental nature of the cosmos, including the distribution of galaxies, dark matter, dark energy, and the overall geometry of space-time. Cosmologists explore the early moments of the universe, moments after the Big Bang, and employ various observational tools, such as telescopes and satellites, to gather data that informs our understanding of cosmic evolution.

Key concepts in cosmology include the expansion of the universe, cosmic microwave background radiation, and the formation of galaxies and large-scale structures. It is a field that intersects with physics, astronomy, and astrophysics, providing insights into the vast and intricate tapestry of the cosmos.

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