Cosmology

The Standard Model of Cosmology is wrong on multiple counts

The Standard Model of Cosmology is also called the Concordance model, which means the currently accepted model. Another name for it is the Lambda-CDM model, where Lambda is the cosmological constant, and CDM is an acronym for cold dark matter. In a nutshell, the Standard Model of Cosmology says the universe started with the Big Bang, which was followed by a very rapid expansion called inflation. After this came the formation of photons and leptons plus other particles, then hydrogen and helium, then stars and galaxies…

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The James Webb Space Telescope and the massive early galaxies

As I was saying last time, there was a interesting news article recently. I saw it in The Telegraph myself. It concerned observations of massive early galaxies by the James Webb Space Telescope (JWST). Written by Joe Pinkstone, the article was dated 26th August 2024, and was called How scientists used black holes to solve mystery of earliest galaxies. Pinkstone told us that early galaxies had long been thought to contain relatively few stars, and so wouldn’t be particularly big or bright. However when the JWST…

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The James Webb Space Telescope

I’m sorry I haven’t posted for months. Part of the reason is that the day job has been extremely tough this year. It’s a lot to do with Covid. As you will know if you’ve applied for a driving licence or booked a flight, a lot of organisations are not functioning effectively right now. That’s due to past layoffs, or staff going part time, or retiring, or “working from home”. In addition, training is more difficult when people are not in the office, and it all…

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The gamma bomb

I’ve always been interested in antigravity. It started when I was when I was six, when Fireball XL5 was on TV. Of course, the spaceship itself was a rail-launched rocket with wings. But Steve Zodiac and crew had a "gravity activator" for artificial gravity inside the ship, plus hover bikes. Hover bikes were a recurring feature in Gerry and Silvia Anderson’s futuristic programmes. I think it was because they were cool, and because it wasn’t easy to make those marionettes walk. Gravity generators or compensators were also…

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We have to talk about LIGO

I’ve mentioned LIGO a couple of times in passing. You know, LIGO, the Laser Interferometer Gravitational Wave Observatory. Rainer Weiss of MIT had a lot to do with the idea back in the 1960s, as did Kip Thorne of Caltech. Things got serious in 1980 when the US National Science Foundation funded prototypes at Caltech and MIT, and funded Weiss to lead a study into a full size interferometer. Construction eventually started in 1994 and was finished in 1997. Observations eventually started in 2002 and stopped…

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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…

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Misconceptions skewered

I was surfing the web the other day, and I came across Sean Carroll’s Preposterous Universe blog. There's a post on there called True Facts About Cosmology (or, Misconceptions Skewered). I thought it looked interesting, because that’s my kind of thing. I do so dislike all the popscience and the lies to children, and it pleases me to see somebody else trying to put the record straight. But has he? I thought I’d take a look and give my opinion. Carroll leads in with something about…

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What energy is

If you ask what is energy? some people will tell you that energy is an abstract thing. This was how Richard Feynman described it in the Feynman lectures, volume I chapter 4. He used the analogy of children’s blocks. He said these blocks were absolutely indestructible and could not be divided. But then he said there are no blocks. Only then he contradicted himself by saying energy has a number of different forms, such as gravitational energy, kinetic energy, and heat energy: Image from Assignment point…

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The fate of the universe

One of the things cosmologists like to talk about is the fate of the universe. Some say it all depends on the density parameter omega: Ω. This started life as the average matter density of the universe divided by a “critical” matter density for the Friedmann universe: Based on the Friedmann universes public domain image by BenRG, see Wikipedia Commons and Wikipedia Nowadays when we talk about omega we don’t restrict ourselves to matter alone. That’s because energy doesn’t necessarily take the form of matter, and…

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The edge of the universe

When you dig into the history of cosmology, some things catch your eye. Things like the “boundary conditions” in Einstein’s 1917 cosmological considerations in the general theory of relativity. Or something Willem de Sitter said in his 1917 paper On the relativity of inertia. Remarks concerning Einstein's latest hypothesis. He said this: “if the gμν at infinity are zero of a sufficiently high order, then the universe is finite in natural measure”. There’s also something Paul Steinhardt said in his 1982 Natural Inflation paper. He said this:…

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