ten things tagged “physics”
Opportunity and luck bestow their benisons upon a once-in-a-generation genius, mathematical mystic, and one of the greatest theoretical physicists to have walked the planet.
You never hear of Dirac much1. I read this article about him being in love and decided to read more about his life and work. This award-winning book came highly recommended. I enjoyed its breadth and depth thoroughly. I am a slow reader and was surprised by the speed at which I got through its heft: 625 pages2! Farmelo expertly weaves world history, politics, religion, and humor into Dirac’s story. The epilogue spends some time conjecturing that he may have been autistic in a bid to explain his many eccentricities and severe taciturnity3. Lots of painful family tragedy that was rather difficult to read. Intuition and Mathematical beauty were paramount to him:
If you are receptive and humble, mathematics will lead you by the hand. Again and again, when I have been at a loss how to proceed, I have just had to wait until [this happened]. It has led me along an unexpected path, a path where new vistas open up, a path leading to new territory, where one can set up a base of operations, from which one can survey the surroundings and plan future progress.
Here’s an In Our Time episode with Farmelo and two other physicists if you want to get a taste of what this excellent and riveting biography is about. I thought this description of Dirac by a young Subrahmanyan Chandrasekhar (who took Dirac’s Quantum Mechanics course at Cambridge four times in 1930 because it was “just like a piece of music you want to hear over and over again”) was rather funny:
“Dirac showed none of the confidence that might be expected of a young man at the top of his game. Chandrasekhar wrote home to his father that he was disappointed that Dirac did not show a bit more swagger: ‘[Dirac is a] lean, meek shy young “Fellow” (FRS) who goes slyly along the streets. He walks quite close to the walls (like a thief!), and is not at all healthy. A contrast to Mr Fowler […] Dirac is pale, thin, and looks terribly overworked.”
Here’s a video of the author giving a presentation on Dirac and Mathematical Beauty
Fat claim, but I cannot imagine anything more badass than this.
I remember seeing an interview with him and the person asking him the question asked him “How was that shot perfectly timed?” He said “I just saw the count down clock and we waited until minus 10 seconds to start recording”.
And there was an assistant doing the count down with his fingers that Burke could se [sic] so Burke could time it perfectly.
Developer site. A beautiful meditation that’s just the right length.
Here’s a Schwarzschild Black Hole, one “with mass, but with no electric charge, and no spin.” (Source)
Best thing I’ve seen this year. About as spiritual as it gets.
After an unimaginable length of time, even the black holes will have evaporated and the universe will be nothing but a sea of photons, gradually tending towards the same temperature, as the expansion of the universe cools them towards absolute zero. Once the very last remnants of the very last stars are finally decayed away to nothing and everything reaches the same temperature, the story of the universe finally comes to an end. For the first time in its life, the Universe will be permanent and unchanging. Entropy finally stops increasing because the cosmos cannot get any more disordered.
Nothing happens. And it keeps not happening forever.
😢 how beautiful is that? And black holes take a long, long time to evaporate
A black hole with the mass of the sun will last a wizened 1067 years. Considering that the current age of our universe is a paltry 13.8 times 109 years, that’s a good amount of time. But if you happened to turn the Eiffel Tower into a black hole, it would evaporate in only about a day.
And that’s after this happens
It will take hundreds of trillions of years for the first stellar remnant to cool completely, fading from a white dwarf through red, infrared and all the way down to a true black dwarf. By that point, the Universe will hardly be forming any new stars at all, and space will be mostly black.
BLN and I spoke about how we simply have no good strategy to attempt a comprehension of “hundreds of trillions” of years.
Minute Physics on how Muons reaching terrestrial detectors from the upper atmosphere are direct proof of time dilation/length contraction in Special Relativity.
What a Boss 🙏 💯
When we arrived we were introduced to Henry Bethe, who is now five years old, but he was not at all impressed. The only thing he would say was “I want Dick. You told me Dick was coming,” and finally he had to be sent off to bed, since Dick (alias Feynman) did not materialise. About half an hour later, Feynman burst into the room, just had time to say “so sorry I’m late. Had a brilliant idea just as I was coming over,” and then dashed upstairs to console Henry. Conversation then ceased while the company listened to the joyful sounds above, sometimes taking the form of a duet and sometimes of a one-man percussion band.
In the evening I mentioned that there were just two problems for which the finiteness of the theory remained to be established; both problems are well-known and feared by physicists, since many long and difficult papers running to fifty pages and more have been written about them, trying unsuccessfully to make the older theories give sensible answers to them. When I mentioned this fact, Feynman said, “We’ll see about this,” and proceeded to sit down and in two hours, before our eyes, obtain finite and sensible answers to both problems. It was the most amazing piece of lightning calculation I have ever witnessed, and the results prove, apart from some unforeseen complication, the consistency of the whole theory.