ten things tagged “physics”

The Strangest Man: The Hidden Life of Paul Dirac, Quantum Genius by Graham Farmelo A

'The Strangest Man: The Hidden Life of Paul Dirac, Quantum Genius' by Graham Farmelo

I was lucky. I went to good schools, I had excellent teachers. I was in the right place at the right time.

Paul Dirac

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.”

Update

Here’s a video of the author giving a presentation on Dirac and Mathematical Beauty

  1. And according to the author, not even in his native Bristol… ↩︎

  2. Well, a hundred or so are copious footnotes and references. ↩︎

  3. And I do mean laughably, alarmingly severe. His colleagues came up with a unit called a “Dirac” which is one word per hour. ↩︎

On Consciousness

It is remarkable that mind enters into our awareness of nature on two separate levels. At the highest level, the level of human consciousness, our minds are somehow directly aware of the complicated flow of electrical and chemical patterns in our brains. At the lowest level, the level of single atoms and electrons, the mind of an observer is again involved in the description of events. Between lies the level of molecular biology, where mechanical models are adequate and mind appears to be irrelevant. But I, as a physicist, cannot help suspecting that there is a logical connection between the two ways in which mind appears in my universe. I cannot help thinking that our awareness of our own brains has something to do with the process which we call ‘observation’ in atomic physics. That is to say, I think our consciousness is not just a passive epiphenomenon carried along by the chemical events in our brains, but is an active agent forcing the molecular complexes to make choices between one quantum state and another. In other words, mind is already inherent in every electron, and the processes of human consciousness differ only in degree but not in kind from the processes of choice between quantum states which we call ‘chance’ when they are made by electrons.

Freeman Dyson

The Most Perfectly Timed Shot in the History of Television

Fat claim, but I cannot imagine anything more badass than this.

Here’s the full video. The presenter’s James Burke. From the YouTube comments:

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.

Timelapse of the Future

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.

Freeman Dyson on Richard Feynman

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.

and

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.

– Freeman Dyson, “Maker of Patterns” (via Nautilus)