Most laymen completely misunderstand what a black hole is

I saw Luboš Motl’s blog post Most laymen completely misunderstand what a black hole is. When I read the title my irony meter skipped a beat, so I thought I’d take a closer look. Especially since he said this in his opening paragraph: One of those invalid memes that I want to discuss… is the idea that the point of the black hole is the singularity. That is what makes a black hole a black hole and that's also where the mysteries of black holes hide.…

Continue Reading Most laymen completely misunderstand what a black hole is

A brief history of black holes

I read Sabine Hossenfelder’s latest blog post yesterday. The title was A brief history of black holes. I left a couple of comments. One was a reply to Louis Marmet, and referred to Oppenheimer’s 1939 frozen star black hole. I said I think the black hole grows like a hailstone, from the inside out. The other was addressed to Hossenfelder, and referred to Einstein talking about the variable speed of light. I said that IMHO this had to mean Penrose/Hawking singularity theorems were wrong. I found…

Continue Reading A brief history of black holes

L-shaped contrails

Sorry I haven't posted much lately. I've been run off my feet with work. Like that woman at the end of Twelve Monkeys, I'm in insurance, and work is pressing. But anyhow, very briefly, I wanted to show you something I saw yesterday evening: L- shaped contrails. At least that's what they looked like: There appears to be two, one lower, one higher. Here's another picture I took a few seconds later: I was in Poole looking west, at circa 18:53 GMT.  Interesting, that! NEXT

Continue Reading L-shaped contrails

The theory of everything

I think when you’ve absorbed a lot of material, especially the old material, you get a handle on the theory of everything. The Einstein digital papers are important for this. That’s where you learn how gravity works. You learn that light curves because the speed of light is spatially variable. Not because it follows the curvature of spacetime. You learn that a gravitational field is a place where a space is neither homogeneous nor isotropic in a non-linear fashion. Hence when you plot your metrical measurements…

Continue Reading The theory of everything


Clunk. That’s the sound of my head hitting my desk. Because the $3m special breakthrough prize has just been awarded to the “discoverers” of supergravity. Yes folks, that’s one of those mathematical “discoveries”. It isn’t like discovering America or penicillin. It’s the sort of “discovery” that people peddle when they’re hyping a hypothesis for which there’s no evidence at all. The prize was awarded to Sergio Ferrara, Daniel Freedman, and Peter van Nieuwenhuizen for an “Influential Theory Combining Gravity with Particle Physics”. Only it isn’t influential…

Continue Reading Supergravity

Misconceptions in gravitational physics

I think it’s safe to say that there are some misconceptions in physics. The issue of course, is how many. That’s where I part company with your average physicist. He’ll tell you that whilst we don’t understand everything, we do understand some things, such as black holes. Only he doesn’t. Take a look at the Wikipedia black hole article. It says this: “a black hole is a region of spacetime exhibiting gravitational acceleration so strong that nothing - no particles or even electromagnetic radiation such as…

Continue Reading Misconceptions in gravitational physics

Quantum gravity is a castle in the air

When you spend some time digging into the history of physics, you find yourself uncovering the foundations of physics, and then you come to appreciate a few things. You come to appreciate how gravity works, and why an electron falls down. It isn’t because gravitons are flying back and forth: Graviton image by Julie Peasley, see You also come to appreciate that light interacts with light to form electrons and positrons in gamma-gamma pair production. You come to appreciate that the electron is not a…

Continue Reading Quantum gravity is a castle in the air

Dark matter

There’s plenty of evidence for dark matter, ranging from velocity dispersion, flat galactic rotation curves, and gravitational lensing. The evidence for dark matter is so good we can even map it out: Image credit NASA, ESA and R. Massey (California Institute of Technology), see There’s also plenty of papers and articles about dark matter candidates. Maxim Khlopov refers to WIMPs, axions, neutrinos, mirror-world particles, extra-dimensional particles, and black holes. Andreas Ringwald refers to neutralinos, gravitinos, sterile neutrinos, and axions. Kim Griest refers to MACHOs, molecular…

Continue Reading Dark matter

Dark matter candidates

Everybody loves a mystery, and one of the best mysteries in physics is dark matter. As to where it starts, check out Brian Koberlain who said its origins can be traced to the 1600s. Or Alexis Bouvard who in 1821 said anomalies in the orbit of Uranus could be caused by dark matter. Or see the Ars Technica history of dark matter article by Stephanie Bucklin. She said in 1884 Lord Kelvin concluded that “many of our supposed thousand million stars, perhaps a great majority of…

Continue Reading Dark matter candidates


The black hole firewall is a relatively recent idea. On Wikipedia you can read how it “was proposed in 2012 by Ahmed Almheiri, Donald Marolf, Joseph Polchinski, and James Sully as a possible solution to an apparent inconsistency in black hole complementarity”. Their proposal is known as the AMPS firewall, and the title of their paper is black holes: complementarity or firewalls? They cannot all be true They start by saying “we argue that the following three statements cannot all be true: (i) Hawking radiation is…

Continue Reading Firewall!