Black Holes Articles

There are two main ways black holes form: direct collapse or a dying star. Just after the moment of creation, energy was spread more or less uniformly through space, but some places were slightly denser than other. As things got jostled around, some of these areas got so dense that they collapsed into a primordial black hole. It’s thought that these probably were the anchors that created the galaxies. When a really really big star starts to finish it’s fuel and sputter out, it’s internal heat can’t keep gravity at bay anymore and as the star collapses in on itself, the core gets so dense it forms a black hole.

Tag Archive for: black holes

gravity collapse

Oppenheimer-Snyder Model of Gravitational Collapse: Mathematical Details

/
0 Comments
Part 1: OverviewPart 2: Mathematical DetailsPart 3: ImplicationsIn a previous article, I described in general terms the model of gravitational…
gravity collapse

The Oppenheimer-Snyder Model of Gravitational Collapse: An Overview

/
0 Comments
Part 1: OverviewPart 2: Mathematical DetailsPart 3: ImplicationsMost people who have spent any time at all studying GR are familiar with the…
Kerr Spacetime

Geodesic Congruences in FRW, Schwarzschild and Kerr Spacetimes

/
5 Comments
Introduction The theory of geodesic congruences is extensively covered in many textbooks (see References); what follows in the introduction is a brief…
Learn the Math

I Know the Math Says so, but Is It Really True?

/
104 Comments
I'm sure anyone who has hung out long enough here on Physics Forums has encountered threads that go something like this (I'll use an example based on threads…
Gaia search for black holes

Gaia Astrometry: Detecting Gravitational Waves Guide

/
1 Comment
Overview Gravitational waves (GWs) are disturbances in spacetime produced by massive objects moving asymmetrically. Only the most massive and most relativistic…
black holes are not empty

VHE Gamma Rays from Sgr A*: Black Holes and CTA Observations

/
9 Comments
Researchers simulating the accretion flow around Sagittarius A*, the supermassive black hole at the Milky Way's center, have found that magnetic reconnection…
what are the black hole thermodynamics

The Four Laws of Black Hole Thermodynamics Explained

/
0 Comments
Black hole thermodynamics consists of four laws that mirror the ordinary laws of thermodynamics: a zeroth law of uniform surface gravity, a first law relating…
What is Mass Inflation

Mass Inflation in Black Holes: Poisson-Israel Theory Explained

/
0 Comments
Mass inflation is the phenomenon in which the internal mass parameter of a rotating or charged black hole grows without bound near the Cauchy horizon,…
killing Fields and Black Holes

Killing Vector Field & Surface Gravity in Kerr BH Explained

/
0 Comments
Killing Vector Field The Killing vector field is a vector field on a differentiable manifold that preserves the spacetime metric. In other words, it generates…
Falling in Black Holes

Radial Infall into a Static Mass: Equations & Guide

/
0 Comments
From Exploring Black Holes by John Wheeler and Edwin Taylor. The relations below apply to any object falling radially toward a static, spherically symmetric…
gps2

The Schwarzschild Metric: The Photon Sphere

/
2 Comments
 A Short Proof of Birkoff's Theorem derived the Schwarzschild metric in units of ##G = c = 1##:\begin{equation} ds^2 = -\left(1 - \frac{2M}{r}\right)dt^2…
SchwarzschildGeometry4

The Schwarzschild Geometry: Physically Reasonable?

/
33 Comments
 In the last article, we looked at various counterintuitive features of the Schwarzschild spacetime geometry, as illustrated in the Kruskal-Szekeres…
SchwarzschildGeometry3

The Schwarzschild Geometry: Spacetime Diagrams

/
12 Comments
 When we left off in part 2, we were looking at the metric for the Schwarzschild geometry in Kruskal-Szekeres coordinates:$$ ds^2 = \frac{32…
SchwarzschildGeometry2

The Schwarzschild Geometry: Coordinates

/
2 Comments
 At the end of part 1, we looked at the form the metric of the Schwarzschild geometry takes in Gullstrand-Painleve coordinates:$$ ds^2…
SchwarzschildGeometry1

The Schwarzschild Geometry: Key Properties

/
22 Comments
 Not long after Einstein published his Field Equation, the first exact solution was found by Karl Schwarzschild. This solution is one of the…
spacetime7

Struggles with the Continuum: General Relativity

/
2 Comments
 Combining electromagnetism with relativity and quantum mechanics led to QED. Last time we saw the immense struggles with the continuum this…

A Black Hole Problem From Greg Egan’s “Incandescence”

/
8 Comments
The following problem was inspired by reading Greg Egan's "Incadescence".  Consider a body, orbiting a Schwarzschild black hole and tide locked to it,…
blackholeexists

Do Black Holes Really Exist?

/
68 Comments
Introduction The purpose of this article is to discuss the title question from several different viewpoints, to show that it isn't as simple as it looks.…
blackholesuniverse

Why the Big Bang Wasn’t a Black Hole: Cosmology Explained

/
7 Comments
The Big Bang was not a black hole because it happened everywhere in space at once rather than at a single point, and because the near-perfect homogeneity…
redshiftblackholes

Time Dilation & Redshift of Schwarzschild Black Holes

/
76 Comments
Time dilation near a Schwarzschild black hole The following is an overview of the time-dilation and gravitational-redshift effects of a static (Schwarzschild)…
matterphoton

Will All Matter Be Converted to Photons?

/
41 Comments
Will all matter be converted into black holes and then photons? No. There is a misconception that a lot of laypeople seem to be picking up recently from…
blackholesforce

An Equation for the Centrifugal Force Reversal Near A Black Hole

/
15 Comments
My goal in this article is to derive a simple equation for the proper acceleration of an observer traveling on a circular path around a Schwarzschild black…
supernova

Star Death Explained: White Dwarfs to Black Holes

/
0 Comments
Stellar death outcomes depend on the star's initial mass: stars below roughly 8 solar masses end as white dwarfs, while more massive stars undergo core…