The Day Feynman Worked Out Black-Hole Radiation on My Blackboard

http://nautil.us/blog/the-day-feynman-worked-out-black_hole-radiation-on-my-blackboard

by dnetesn • 7 years ago

135 60 7 years ago

nautil.us

neilv2• 7 years ago

I don't think I'll ever get tired of Feynman stories.

mrmondo2• 7 years ago

You and I both, if you haven’t already - read ‘Surely you must be joking, Mr Feynman!”

neilv2• 7 years ago

Some other good ones on the 'net:

"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

nihil75• 7 years ago

Do cleaning staff actually wipe blackboards at Caltec?

Makes me question the authenticity of the story.

varelaz• 7 years ago

but quantum representation of this information still lives somewhere in the Universe

YayamiOmate• 7 years ago

Yea, also it seems that "had it all" might be an exaggeration... there are lots of mathematical technical details that go into those papers.

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.

nabla92• 7 years ago

I think Lightman uses artistic license a lot and has rehearsed the story mulitple times in his mind. Lightman is a writer who wrote 'Einstein's Dreams'. This article is basically transcript of the interview from 2014. http://nautil.us/blog/why-hawking-radiation-was-almost-feynm...

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.

gumby2• 7 years ago

Another weird think in the interview is Lightman saying that he don't think Feynman didn't have a big ego.

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?

IshKebab• 7 years ago

Yeah I find this very hard to believe. Cleaners don't even erase whiteboards and unimportant ordinary companies.

aj7• 7 years ago

Exactly. The first thing they teach janitors in universities is to never touch the blackboards in offices.

comboy• 7 years ago

This just says he came to the conclusion that there should be spontaneous emission and estimated it. Coming up with how it actually happens (particle-antiparticle pair) is another story, so it seems a bit unfair to Hawking to say that Feynman got it first.

coldtea• 7 years ago

What other thing could be the emission?

Besides, isn't particle-antiparticle pair obvious, if one knows about their spontaneous appearance?

nocturnial• 7 years ago

The particle-antiparticle explanation is just an analogy and doesn't really cover what actually happens. I thought this video from PBS Space Time explains it really well while keeping it accessible for non-physicists: https://www.youtube.com/watch?v=qPKj0YnKANw

terryf4• 7 years ago

It's more complex than that. If it was that simple, it would emit particles and antiparticles randomly which would not lead to losing mass.

mannykannot4• 7 years ago

I am always skeptical of retrospective claims of obviousness (partly from the number of times I have seen it made in math textbooks.)

scrooched_moose• 7 years ago

Also, this says it was a year before Hawking published his paper. Presumably he'd been working on it for quite a while before he published so I'm not sure it's fair to say Feynman was "first".

mannykannot4• 7 years ago

This isn't about priority, and that is clearly something that Feynman did not care about. It is about Feynman's astonishing ability to make fruitful connections.

jpmattia• 7 years ago

Coming up with how it actually happens (particle-antiparticle pair) is another story, so it seems a bit unfair to Hawking to say that Feynman got it first.

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.

vanderZwan2• 7 years ago

But when I got back to my office in the morning, the cleaning lady had wiped the blackboard clean.

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?

reallymental• 7 years ago

Perhaps you're thinking of Fermat[0], who famously remarked "I have discovered a truly remarkable proof of this theorem which this margin is too small to contain.", and promptly proceeded to take the solution with him to the other side.

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.

[0] https://en.wikiquote.org/wiki/Pierre_de_Fermat

tragomaskhalos• 7 years ago

Isn't the accepted version of this that Fermat thought he had an elegant solution, but had actually made some simple logical error in his reasoning? And Andrew Wiles' solution is certainly not simple. However it is very seductive to imagine that Fermat was correct, and it's just that no-one since has had the insight to rediscover it.

vanderZwan2• 7 years ago

No I think it was more someone like Riemann, Abel or Gauss, but I can't find any proof of this being true for any of them.

Probably one of those apocryphal stories that died when the internet came along (I remember first hearing of this two decades ago).

ginnungagap• 7 years ago

You might be thinking of Riemann, who died in Italy leaving some unpublished notes in Göttingen that were thrown away by his housekeeper

foobarbecue• 7 years ago

`Feynman said that what Bill and Saul were describing sounded like simulated emission...`

Proof we live in a simulation! (presumably this is a typo)

anacleto3• 7 years ago

Kinda reminds of me Fermat's equation though.

zeristor2• 7 years ago

This made me wonder if Rick Sanchez was based on Richard Feynman?

fwip• 7 years ago

They're both assholes, so definitely possible.

Retra2• 7 years ago

I thought it was well-known he was based on Doc Brown, and transitively, Albert Einstein.

zeristor2• 7 years ago

I know that, but Feynman seems more fitting

bjornsing• 7 years ago

Sounds credible, up to the point about the cleaning lady... If he realized their importance, why would he not be able to work out the equations again, possibly with Feynman’s help?

huhtenberg• 7 years ago

Precisely!

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.

JoeAltmaier• 7 years ago

Was that true in the 1050's? 1960's? Back then, the upper-class folk who inhabited offices would not think of emptying a wastepaper basket, clearing a desk, cleaning a floor. They may have had different expectations about who's job it was to erase the chalkboard as well.

paulpauper• 7 years ago

there are multiple derivations. my guess is he used the simpler of the two that does not require the field equation: https://en.wikipedia.org/wiki/Hawking_radiation

mannykannot4• 7 years ago

Feynman's argument is made from a phenomenon predicted for rotating black holes, that is analogous to stimulated emission. I believe Hawking radiation is predicted for all black holes, whether rotating or not, so I am wondering if there is a phenomenon analogous to stimulated emission from non-rotating black holes? (I am making an analogy of analogies here: if the original phenomenon is like stimulated emission from rotating black holes, and Hawking radiation is the corresponding spontaneous emission, then is Hawking radiation from stationary black holes also like spontaneous emission, and if so, what is the corresponding stimulated emission?)

StopClickBait• 7 years ago

This story may or may not be true, either way it encapsulates what a scientist should be: distracted by reality and allowing other smart people to play their roles. Feynman had his own things to work on, and clearly there were more people needed for humans to advance.

Mugwort• 7 years ago

This is not at all unusual. Poincare discovered special relativity before Einstein, Hilbert found the correct equations for General relativity one week before Einstein, Hamilton almost discovered quantum mechanics decades before everyone else. Newton found solutions to major mathematical problems and never published them. Gauss discovered hyperbolic geometry before Bolyai and Lobachevski and never bothered publishing his results. I can go on and on in the fields of physics and mathematics which I know best. Certainly, the same thing is true in chemistry, biology, etc. I wouldn't doubt someone got there before even Feynman did. Still in every case, the recognized discoverer not only made their discoveries independently but also managed to convince their communities of their merit, something which is FAR harder to do.

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.

stcredzero2• 7 years ago

This smells like classic Feynman. He did more things than people realize...

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?"

fosco• 7 years ago

Mathematics is discovered not invented.

The way I understand it.

CalChris2• 7 years ago

The article doesn't explain why light would bounce off a rotating black hole and that doesn't make intuitive sense to me. I think of light as bouncing off of surfaces and I think of a black hole as being an event horizon and stuff inside. Does anyone have an explanation for this?

lostmsu• 7 years ago

AFAIK, Hawking got the idea of black hole radiation from Zeldovich. See https://en.m.wikipedia.org/wiki/Hawking_radiation#Discovery

The Day Feynman Worked Out Black-Hole Radiation on My Blackboard

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