by Matthew Cobb
PCC(E) is still in the internet-less wilds of Ultima Thule, but he will be back.
Meanwhile, in Dobrzyn, Hili is musing on the apparent immutability of the universe:
Hili: Everything seems to be the same.
Me: Yes, and sometimes that’s very annoying.
In Polish:
Hili: Wszystko wydaje się być takie same.
Ja: Tak i chwilami to jest bardzo irytujące.
To keep you all busy, here’s a challenge. Explain magnetism, or gravity, both of which are basically magic.
Gravity is a no-brainer. We* don’t know what it is or how/why it works. Magnetism, we* have a better idea, but it is still profoundly mysterious. To give you some idea of the problem, here’s Feynman explaining the inexplicable, posted by Tuomas Pernu in reply to me on bsky:
*We = physicists. I have no idea.
“So I have cheated very badly”. Love it.
Thank you Matthew.
Uh oh Hii: stasis?
My undergrad physics days in the 1960’s coincided with Feynman’s Lectures in Physics series on a collection of black and white (16mm?) movie reels that were a weekly afterclass draw to our physics building lecture hall. I followed Feynman through the later trade book publications by and about him and his time on the Rogers Commission with his very important Appendix F dissent investigating the Space Shuttle Challenger disaster. I think it was Feynman who remarked that anyone who says he understands quantum mechanics doesn’t understand quantum mechanics.
Btw, when I taught high school physics in the early 70’s), my kids were amazed in general and upset in some cases (but remembered in all cases) to find out that their holding hands and kissing was simply electro-magnetic repulsion between the electron clouds surfacing the boy’s and girl’s hands and lips.
“Two sets of orbicular muscles juxtaposed in a mutual state of contraction,” according to my beloved 10th grade earth science teacher, with whom I remained close friends until the end of his life. I remain friends with his wife. Your comment about kissing reminded me of his similarly mechanistic description.
To which the smart ass in the back row says: if these are universal forces, then why is it that one set of lips repels while another attracts—and still others attract very, very much?
I can’t believe I listened to Feynman before finishing my first cup of coffee. Without caffeine, me human kind cannot bear very much reality.
Edit: and obviously can’t place a comment in the proper place, either. For Jim @ #2.
Not a physicist backside.
But here goes, we know more about gravity today than we did yesterday.
Einstein’s “general relativity” explains what it can do up until the inside of a black hole… and how GPS works, predicted gravitional waves, which incredibly “we” have measured and confirmed. I know nothing about quantum gravity and here “we” are altogether… and us, the interested.
The motion of Mercury and the bending of light around a mass. It is not a force but the warping of space time, it tells it how to bend it like Beckham.
The “we” are looking for the graviton but it is so weak and teeny, apparently we’d have a better chance finding a god but technically as of today, it is out of the “we” collective reach.
I may be wrong but I tried.
Someone who seemed to know things explained to me once that sub-atomic particles could be considered as very tiny bits of space, curved around on itself. Taking that, I try to extrapolate that gravity is made by the combination of tiny bits of curved space, all from lots and lots of sub-atomic particles when they are bunched together.
Ultimately all explanations of physical phenomena either generate an infinite regress of further questions or else the explanations become circular. A simple example of circular explanation is Newton’s second law F = ma.
Q: What is force? A: Force is that which causes a body with inertial mass m to accelerate according to the formula F = ma.
Great. If I know what inertial mass is, I know what force is. But now I can ask:
Q: What is inertial mass? A: inertial mass is a scalar quantity that describes the reluctance of a body to accelerate in response to an applied force.
It seems that the concepts of force and inertial mass only make sense if we define them together. In a similar way we get a definitional circle when we discuss electric charge and electric fields. We define the electric charge of a particle in terms of the force the particle experiences in the presence of an electric field and you define an electric field in terms of the force it exerts on charged particles.
It is turtles all the way down and sometimes there are circles of turtles as well as infinite linear stacks of turtles.
One of my favorites of Feynman’s Greatest Hits.
Would have been interesting know him – the ultimate weird genius. And quite a party animal by many accounts. 😉
D.A.
NYC
David, having served on numerous K-12 science and math textbook review committees over the years, my favorite Feynman story, and I think maybe the source of the line, “surely you’re joking Mr Feynman”, was his service on the California high school physics textbook review committee. (He got lots of these type requests after winning the Nobel, a constant source of irritation it seemed). Among the incidents was the supervisor trying to put him down when his review of a particular book was well below that of a team of mcdonnell aircraft co engineers. She said that surely he did not think himself smarter than twenty engineers from Mcdonnell aircraft. Feynman replied that he is sure that mcdonnell has some very bright engineers and one or two might be smarter than he, but that yes, he is smarter than the AVERAGE of any twenty of their engineers. Numbers are approximate to my recollection, but the idea is correct)
Feynman was an interesting person, and lecturer. I had him for introductory physics lectures at Caltech in 1962. He was very open to student visits, and even invited us to some of his parties at properties above Pasadena. I particularly remember one at a property owned by Alberto Vargas who produced the vargas pin ups for Playboy. Feynman wasn’t your typical faculty member! You can read free, high resolution copies of the Feynman lectures at: https://www.feynmanlectures.caltech.edu/info/flp.html
Wow. Somebody who he taught in ‘62 at Caltech! When I came in to take over the high school physics class from a chemistry teacher in 1971, i was given a small but adequate budget to purchase physics-related books for the school library. First thing I purchased was two sets of the Feynman Lectures: one for the library shelves and one for the top of my desk in the physics lab…so kids would have easy access and be encouraged to share readings.
Feynman was an interesting person, and lecturer. I had him for introductory physics lectures at Caltech in 1962. He was very open to student visits, and even invited us to some of his parties at properties above Pasadena. I particularly remember one at a property owned by Alberto Vargas who produced the vargas pin ups for Playboy. Feynman wasn’t your typical faculty member! You can read free, high resolution copies of the Feynman lectures at: https://www.feynmanlectures.caltech.edu/info/flp.html
A more direct URL is https://www.feynmanlectures.caltech.edu
Someone recently ridiculed the “sex is more complicated than a binary” argument on X by replying, ‘Gravity is absolutely more complicated than “things fall down,” but not so much so that they don’t.’ https://x.com/suzanne_moore/status/1940861586790666410
Missed this yesterday Jez. Excellent line! Thanks