4 ms·

When you stop and look at QCD in the big picture, it's sort of shocking how little we know - like, really, really know - about the internal structure of the pro

When you stop and look at QCD in the big picture, it's sort of shocking how little we know - like, really, really know - about the internal structure of the proton, or even the nucleon! It's the curse of "probing" with massive energies. No one's a hundred percent certain of whether they're detecting something that's actually there - like there there - or whether they're looking at by-product of enormous collision energies. Physicists are smart people! I could never do what they do. But there's a limit to certainty, and inside the proton especially there's unknown first principles at work. Bringing the precision of photons and lasers into this nucleon party is going to be huge. I can't wait!

javajosh 2y ago
Yeah and maybe we could do GR experiments on a table top. Gravity goes as 1/r^2 so a small r might make the mass terms irrelevant, and you could check GR in various ways [1] especially Shapiro delay[2]. This would, in turn, give a way to probe quantum gravity effects. 1 - https://en.wikipedia.org/wiki/Tests_of_general_relativity https://en.wikipedia.org/wiki/Tests_of_general_relativity 2 - https://en.wikipedia.org/wiki/Shapiro_time_delay https://en.wikipedia.org/wiki/Shapiro_time_delay
blackoil 2y ago
> it's sort of shocking how little we know To my feeble mind, it's shocking how much we know.
- purplerabbit 2y ago
  Our knowledge and ignorance are both astounding. But there's definitely more we don't know than that we know.
- MilStdJunkie 2y ago
  Speaking for myself, as a layman, I had always been walking around thinking of hadrons as balls with other balls inside, with forces mediated by tiny/insubstantial yet-to-be-discovered balls. Yes, I knew they weren't balls, exactly, but still. Newer models with greater sensitivity have sort of pulled a fast one: that maybe the balls are a side effect of the way we look at them. More precisely, to look at them, we need to smack them hella hard, to make the balls come out where we can see them. But the smacking might be a part of why the balls look like balls! The native hadron in its natural habitat might be something fantastically more complex, a sort of cell biology of energies all competing and vibrating, and they're part of the interrelated forces of the nucleus itself - we might even use that obsolete term return, the "nucleon", to represent this complex. Jiving against all of this are new ideas about what mass actually is, defining spatial attributes as degrees of freedom, and all sorts of new thoughts. It's super exciting. So that's what I mean by "shocked how little we know", because what we did think we knew got oversold as a World of Balls. But who knows?! Maybe this neat laser thing can help find more answers.

javajosh 2y ago

Yeah and maybe we could do GR experiments on a table top. Gravity goes as 1/r^2 so a small r might make the mass terms irrelevant, and you could check GR in various ways [1] especially Shapiro delay[2]. This would, in turn, give a way to probe quantum gravity effects. 1 - https://en.wikipedia.org/wiki/Tests_of_general_relativity https://en.wikipedia.org/wiki/Tests_of_general_relativity 2 - https://en.wikipedia.org/wiki/Shapiro_time_delay https://en.wikipedia.org/wiki/Shapiro_time_delay

blackoil 2y ago

> it's sort of shocking how little we know To my feeble mind, it's shocking how much we know.

purplerabbit 2y ago
Our knowledge and ignorance are both astounding. But there's definitely more we don't know than that we know.
MilStdJunkie 2y ago
Speaking for myself, as a layman, I had always been walking around thinking of hadrons as balls with other balls inside, with forces mediated by tiny/insubstantial yet-to-be-discovered balls. Yes, I knew they weren't balls, exactly, but still. Newer models with greater sensitivity have sort of pulled a fast one: that maybe the balls are a side effect of the way we look at them. More precisely, to look at them, we need to smack them hella hard, to make the balls come out where we can see them. But the smacking might be a part of why the balls look like balls! The native hadron in its natural habitat might be something fantastically more complex, a sort of cell biology of energies all competing and vibrating, and they're part of the interrelated forces of the nucleus itself - we might even use that obsolete term return, the "nucleon", to represent this complex. Jiving against all of this are new ideas about what mass actually is, defining spatial attributes as degrees of freedom, and all sorts of new thoughts. It's super exciting. So that's what I mean by "shocked how little we know", because what we did think we knew got oversold as a World of Balls. But who knows?! Maybe this neat laser thing can help find more answers.