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Universe Articles

Tag Archive for: universe

infinite universe

Open, Flat & Closed Universes: Curvature Explained

March 16, 2024
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0 Comments
Standard cosmological models are classified by spatial curvature into three broad types: open, flat, and closed universes. These correspond to negative,…
https://www.physicsforums.com/insights/wp-content/uploads/2024/11/infinite-universe.png 135 240 Greg Bernhardt https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Greg Bernhardt2024-03-16 10:35:042026-04-05 14:05:22Open, Flat & Closed Universes: Curvature Explained
Evidence for Big Bang

Big Bang Evidence: CMB, Redshift & Element Abundances

April 6, 2020
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2 Comments
Big Bang: Key PointsHubble's law (redshift of galaxies) and the Doppler effect provide direct evidence that the universe is expanding away from our…
https://www.physicsforums.com/insights/wp-content/uploads/2020/04/is_there_evidence_for_big_bang.png 135 240 Mark R Smith https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Mark R Smith2020-04-06 09:01:152026-02-17 07:28:07Big Bang Evidence: CMB, Redshift & Element Abundances
Cosmic Web Connections

Cosmic Web Connectivity: How It Shapes Galaxy Evolution

March 30, 2020
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1 Comment
Introduction The universe was not perfectly uniform at the beginning; some regions had higher density than others. Over time these higher-density regions…
https://www.physicsforums.com/insights/wp-content/uploads/2020/03/cosmic_web.png 135 240 Mark R Smith https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Mark R Smith2020-03-30 11:32:502026-02-17 07:27:21Cosmic Web Connectivity: How It Shapes Galaxy Evolution
bb_infinity2

Intro to the Big Bang and Infinity Concepts

January 27, 2018
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34 Comments
In the cosmology section of the Physics Forums, I encountered many Big Bang and related infinity problems. Hence, in this article, I want to explain the…
https://www.physicsforums.com/insights/wp-content/uploads/2018/01/bb_infinity2.png 135 240 Arman777 https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Arman7772018-01-27 15:05:272024-12-06 21:31:13Intro to the Big Bang and Infinity Concepts
journeycosmos3

Learn About the FLRW Metric and The Friedmann Equation

January 9, 2018
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1 Comment
Previous Chapter: A Journey Into the Cosmos – The Friedmann Equation                Chapter 2- FLRW Metric and The Friedmann Equation In…
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expandinguniverse

Explore Coordinate Dependent Statements in an Expanding Universe

January 6, 2018
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4 Comments
In this Insight, we will discuss the general Robertson-Walker (RW) universe, in which a set of co-moving observers with proper time ##t## observe the universe…
https://www.physicsforums.com/insights/wp-content/uploads/2018/01/expandinguniverse.png 135 240 Orodruin https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Orodruin2018-01-06 18:34:102024-08-17 16:22:14Explore Coordinate Dependent Statements in an Expanding Universe
cosmosintro

Learn About the Friedmann Equation and the Cosmos

December 22, 2017
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6 Comments
This is an introduction to cosmology for someone who has some knowledge of calculus and basic physics. In this tutorial, we will take a journey into the…
https://www.physicsforums.com/insights/wp-content/uploads/2017/12/cosmosintro.png 135 240 Arman777 https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Arman7772017-12-22 06:24:202024-12-06 21:31:13Learn About the Friedmann Equation and the Cosmos
inflation5

A Poor Man’s CMB Primer: Quantum Seeds

July 26, 2017
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11 Comments
 The CMB establishes a record of ancient acoustic oscillations in the baryon-photon plasma. We've been studying how these primordial sound…
https://www.physicsforums.com/insights/wp-content/uploads/2017/07/inflation5.png 135 240 Brian Powell https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Brian Powell2017-07-26 20:37:282024-12-06 21:31:20A Poor Man’s CMB Primer: Quantum Seeds
universestart

Did the Big Bang Have a Center? Explaining Cosmology

June 10, 2016
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28 Comments
Did the Big Bang Have a Center? What the standard models say According to standard cosmological models based on general relativity — and which agree…
https://www.physicsforums.com/insights/wp-content/uploads/2016/06/universestart.png 135 240 Multiple_Authors https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Multiple_Authors2016-06-10 22:08:392026-01-21 16:53:48Did the Big Bang Have a Center? Explaining Cosmology
universeexpand

Big Bang Models: Expansion, Dark Energy, Inflation

March 26, 2016
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29 Comments
Big Bang and expansion (no inflation, no dark energy) Empty-universe solution (FLRW) Einstein's General Relativity allows a solution (the FLRW metric)…
https://www.physicsforums.com/insights/wp-content/uploads/2016/01/universeexpand.png 135 240 nikkkom https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png nikkkom2016-03-26 17:33:432026-02-16 20:49:59Big Bang Models: Expansion, Dark Energy, Inflation
lightcone7_3

LightCone 8 Tutorial Part III – How Things are Computed

February 11, 2016
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1 Comment
In Part I and Part II of this mini-series, we have briefly discussed the basic user interface and the use of charts to depict the LCDM cosmological model.…
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lightcone72

LightCone8 Tutorial Part II – Charts

January 26, 2016
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3 Comments
Part I dealt with the basic user interface of LightCone8. This part of the tutorial is about potentially useful cosmological insights to be gained from…
https://www.physicsforums.com/insights/wp-content/uploads/2016/01/lightcone72.png 135 240 Jorrie https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Jorrie2016-01-26 23:24:422025-03-24 15:16:09LightCone8 Tutorial Part II – Charts
earlyuniverse

Was the Early Universe in a Disordered State?

December 29, 2015
No. The second law of thermodynamics says that entropy can only increase, so if the early universe had been in a state of maximum entropy, then the cosmos…
https://www.physicsforums.com/insights/wp-content/uploads/2015/12/earlyuniverse.png 135 240 bcrowell https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png bcrowell2015-12-29 23:45:482026-02-16 18:33:08Was the Early Universe in a Disordered State?
observableuniverse

Why the Observable Universe Radius Exceeds Its Age

December 13, 2015
The radius of the observable universe is about 46 billion light-years, which is considerably greater than its age of about 14 billion years. The radius…
https://www.physicsforums.com/insights/wp-content/uploads/2015/12/observableuniverse.png 135 240 Multiple_Authors https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Multiple_Authors2015-12-13 20:29:402026-01-21 16:49:31Why the Observable Universe Radius Exceeds Its Age
steadystate

What Is the Steady-state Model and Why It’s No Longer Viable

December 8, 2015
Introduction to the Steady State Model Back in 2011, I wrote a FAQ entry for Physics Forums on the steady state model and why it is no longer viable.…
https://www.physicsforums.com/insights/wp-content/uploads/2015/12/steadystate.png 135 240 bcrowell https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png bcrowell2015-12-08 14:37:432024-08-17 06:38:50What Is the Steady-state Model and Why It’s No Longer Viable
blackholesuniverse

Why the Early Big Bang Universe Didn’t Form a Black Hole

November 30, 2015
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7 Comments
Why the Big Bang Is Not a Black Hole In the early universe, the matter was gathered together at very high density — so why wasn't it a black hole?Big…
https://www.physicsforums.com/insights/wp-content/uploads/2015/11/blackholesuniverse.png 135 240 Multiple_Authors https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Multiple_Authors2015-11-30 00:47:482026-02-16 18:29:29Why the Early Big Bang Universe Didn’t Form a Black Hole
universespinning

Is the Universe Rotating? Evidence, Tests & Limits

November 10, 2015
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3 Comments
Can we tell whether the universe is rotating? If you believe wholeheartedly in Mach's principle, there is no way to test empirically for the rotation…
https://www.physicsforums.com/insights/wp-content/uploads/2015/11/universespinning.png 135 240 Multiple_Authors https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Multiple_Authors2015-11-10 13:30:352026-01-21 16:40:36Is the Universe Rotating? Evidence, Tests & Limits
birthcmb

A Poor Man’s CMB Primer: The Birth of a Cosmic Background Radiation

September 18, 2015
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3 Comments
 The early universe was hot. So hot that nuclei boiled. The great thermal energy of the universe overwhelmed the confining efforts of the…
https://www.physicsforums.com/insights/wp-content/uploads/2015/09/birthcmb.png 135 240 Brian Powell https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Brian Powell2015-09-18 19:34:532024-09-30 14:40:45A Poor Man’s CMB Primer: The Birth of a Cosmic Background Radiation
balloonanalogy

Balloon Analogy Explained: Cosmology, Expansion & Limits

September 16, 2015
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62 Comments
The Balloon Analogy is a straightforward way to illustrate — without being complete — two important points of modern cosmology that many people find…
https://www.physicsforums.com/insights/wp-content/uploads/2015/09/balloonanalogy.png 135 240 phinds https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png phinds2015-09-16 16:50:452026-02-16 17:09:05Balloon Analogy Explained: Cosmology, Expansion & Limits
cmb

A Poor Man’s CMB Primer: Orientation of the Universe

September 11, 2015
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4 Comments
 This is a picture of the cosmic microwave background:Fig 1. The cosmic microwave background as seen by the European Space Agency's…
https://www.physicsforums.com/insights/wp-content/uploads/2015/09/cmb.png 135 240 Brian Powell https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Brian Powell2015-09-11 13:19:412024-11-16 10:47:40A Poor Man’s CMB Primer: Orientation of the Universe
CosmologicalHorizons

Inflationary Misconceptions and the Basics of Cosmological Horizons

August 28, 2015
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45 Comments
Introduction It is a common saying that during inflation "space expanded faster than the speed of light."  This statement is meant to articulate the…
https://www.physicsforums.com/insights/wp-content/uploads/2015/08/CosmologicalHorizons.png 135 240 Brian Powell https://www.physicsforums.com/insights/wp-content/uploads/2019/02/Physics_Forums_Insights_logo.png Brian Powell2015-08-28 12:08:402024-08-16 08:40:07Inflationary Misconceptions and the Basics of Cosmological Horizons

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