The Day Feynman Worked Out Black-Hole Radiation on My Blackboard
nautil.us
nautil.us
This smells like classic Feynman. He did more things than people realize even coming up with his own ideas about the Riemann hypothesis even though he wasn't a mathematician at all. In a certain sense Feynman didn't discover a single physical law. (arguable) . This little anecdote if true would be Feynman's "single" discovery of an actual new physic law (which happens to not have experimental verification).
Feynman was brilliant. If you have a physics PhD you can still benefit enormously by reading Feynman's lectures on physics. His work on statistical mechanics is essential reading too especially if you already know everything.
He used to be ribbing Danny Hillis all the time, saying that he came up with just about all of Computer Science during the Manhattan Project. "Just what is it that you do again?"
The way I understand it.
Besides, isn't particle-antiparticle pair obvious, if one knows about their spontaneous appearance?
https://www.youtube.com/watch?v=7cj6oiFDEXc
Any time we accelerate, we produce a distant effective event horizon behind us! Also, "The Unruh" would make for a good name for aliens in Star Control!
Quick thought experiment: two particle-antiparticle pairs get created:
p1-ap1, p2-ap2
In regular space, after a very short amount of time p1 annihilates with ap1 and p2 with ap2. Net result is zero additional matter and energy, otherwise we'd just be creating random matter and/or energy everywhere.
If the same happens at the event horizon of a black hole and let's assume purely by chance, p1 and ap2 fall in and p2 and ap1 do not. After a short while, p1 and ap2 annihilate inside and p2 and ap1 outside. The result should be effectively the same as in the previous case, thus zero net energy and/or matter on either side. Thus, also no radiation and mass loss.
It'd be nice if an actual physicist chimed in at this point and told me where I went wrong :)
For the charge to matter, you're saying that charges infer positive or negative mass. But that's original responder's point.... both the particle and anti-particle both have positive mass regardless of their charge, which is a different attribute.
Consider how it is you are conserving energy/mass in your thought experiment. Seems like you might be creating a back door whereby that mass/energy is not conserved in order to preserve charge conservation.
The actual physicist is Richard Feynman, and here is a Feynman diagram of a particle-antiparticle annihilation.
* https://commons.wikimedia.org/wiki/File:Mutual_Annihilation_...
I agree with you about your claim, but not about your justification. I believe that "historically obvious" things ("that's the first thing I would have thought of in that situation; how did it take them so long?") are usually subject to considerable ex post facto bias.
On the other hand, when a mathematics textbook says that something is obvious, it means, or should mean: we've specifically set up the presentation to this point so that there's a unique best way to assemble the material so far, and that unique best way will accomplish the next step. This isn't always true when it's claimed, but it is possible in textbooks in a way that it isn't (or that has only a small probability) in history, since textbooks are consciously organised and history isn't.
It is analogous to evolution of how stimulated and spontaneous emission were explained microscopically in the first place:
For the case of general photon behavior, Einstein showed that the statistics of photons phenomenologically demanded that there be a stimulated process; and then (several decades later) QED provided a microscopic description of how stimulated and spontaneous processes work.
For the case of black holes, it seemed that Feynman noticed that a stimulated-like process was occurring, which (again, probably because of statistics) phenomenologically demands that there be an associated spontaneous process; and then (merely one year later) Hawking provided a microscopic description of how the spontaneous process works.
To be honest, I've never heard anyone talk about stimulated emission from black holes in the context of Hawking radiation, but perhaps it is well-known to those in the field.
Makes me question the authenticity of the story.
I consider Feynman my idol, and he certainly could have had such idea and a shot at theory, but blackboard scribbling seems closer to napkin than a fullfledged theoretical paper.
Nevertheless, cool story.
Another weird think in the interview is Lightman saying that he don't think Feynman didn't have a big ego.
Feynman loved Feynman stories and was very intellectually very competitive with his peers. His reputation and those stories were not completely spontaneous. His breakup with Gell-Mann came because he sometimes forgot that it was not he who invented all those ideas they came up together.
I think one of the things that makes Feynman a bigger than life characters are his quirks and personality. There is no need to clean up his image into some king of humble guy.
I only got to know him pretty late in his life (when he was in Boston) and FWIW, compared to many folks around MIT he was not especially or showily egotistical and he had the time to talk to random students about interesting things. He was more patient than most of the MIT faculty.
I can't say I was some sort of pal or anything so perhaps I got the benefit of a more edited persona?
Ego is weird word because it can mean opposite things in common use. "Weak ego" - person is easily upset when their identity is challenged. "Strong ego" or "big ego" - used as positive thing, opposite of weak ego. "big ego" - used negatively as synonym for egoistic, selfish or self centered. "egotistic" - excessive and objectionable reference to oneself in conversation or writing; conceit; boastfulness, selfishness
"Richard Feynman and the Connection Machine" http://longnow.org/essays/richard-feynman-connection-machine... and a smaller TEDx talk on the same topic by Danny Hillis: https://www.youtube.com/watch?v=8CKW4A6jnJA
"Los Alamos from Below" https://www.youtube.com/watch?v=_aKM-MeDMSI
Violating the sanctity of one's blackboards is one of the worst possible offenses in the academic world. Cleaning staff sure knows better than even glancing in their approximate direction.
Didn't something that happen to the notes of a very famous mathematician as well? That they were burned by the person cleaning up his belongings after he died?
I doubt anyone burned his manuscripts however, but I seem to recall an article where they mentioned that everyone searched for the solution (or for his approach) in every one of his notebooks, but couldn't find it.
Agree on that part. (:
Probably one of those apocryphal stories that died when the internet came along (I remember first hearing of this two decades ago).
Proof we live in a simulation! (presumably this is a typo)