Gamma ray bursts

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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Of mice and men, and what must the neighbours think of us?

I don’t like mice. I saw one last Saturday night. I was sitting at our kitchen bar at maybe 8pm having a glass of wine with the wife. A movement out on the patio caught my eye, and there it was. A mouse. I swivelled on my stool and watched it through the French windows. It was jumping around all over the place in a crazy kind of way. Maybe it was after some bits of food I’d thrown out for the seagull earlier. The seagull…

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UFOs and Aliens

It’s a big big universe. The diameter of the Earth is about eight thousand miles, so the circumference is about twenty five thousand miles. If you could walk twenty miles a day and didn’t have to worry about little things like rivers and mountains and oceans, it would take you one thousand two hundred and fifty days to walk twenty five thousand miles. That’s over three years. The Moon is about two hundred and fifty thousand miles away. If you could walk to the Moon, it…

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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 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…

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Firewall!

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…

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