You can't see a photon, but you can taste a proton.
Is this true or just a pun? Like your acid taste buds are literally sensitive enough to register a single H+ binding?
Can a Human See a Single Photon? (1996)
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Re: Can a Human See a Single Photon? (1996)
#12You can't see a photon, but you can taste a proton.
Is this true or just a pun? Like your acid taste buds are literally sensitive enough to register a single H+ binding?
It is true you can taste protons. Whether you can taste a single one, I'm not sure, nor even how to test it.
Fun video by Steve Mould on the subject: https://www.youtube.com/watch?v=FSYE1T5d9jc
Re: Can a Human See a Single Photon? (1996)
#13I’ve been aware of this fact as Feynman points it out in the course of the lectures, but find it totally nuts — there is some sense of scale I’m missing. Matter consists of discrete chunks, atoms, but these chunks are so infinitesimal and numerous that there is no question of seeing them and any effect involving a handful of them is far, far below the human scale. Light also comes in chunks, and the number of these c…
Really interesting. I'm not an expert, but I'll armchair speculate here.
We need 5-9 photons to merit perception. For us to see one atom, we would need 5+ photons to bounce off of that atom directly to our eyeballs in 100ms. Since both these things are so tiny, most photons miss the atom altogether. It's only when you have large numbers of atoms, densely arranged, that conditions create visibility.
Re: Can a Human See a Single Photon? (1996)
#14You can't see a photon, but you can taste a proton.
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Re: Can a Human See a Single Photon? (1996)
#15Recent experiments have put the claim to test
Overview https://www.nature.com/articles/nature.2016.20282
The actual work https://www.nature.com/articles/ncomms12172
> Here we report that humans can detect a single-photon incident on the cornea with a probability significantly above chance.
Re: Can a Human See a Single Photon? (1996)
#16I’ve been aware of this fact as Feynman points it out in the course of the lectures, but find it totally nuts — there is some sense of scale I’m missing. Matter consists of discrete chunks, atoms, but these chunks are so infinitesimal and numerous that there is no question of seeing them and any effect involving a handful of them is far, far below the human scale. Light also comes in chunks, and the number of these c…
Its my understanding that the human finger, run across an extremely flat surface, can detect a (via a quick google: https://www.newscientist.com/article/2276384-your-finger-can...)
Re: Can a Human See a Single Photon? (1996)
#17You can't see a photon, but you can taste a proton.
Is this true or just a pun? Like your acid taste buds are literally sensitive enough to register a single H+ binding?
Our detection threshold for citric acid is like 0.04 mM (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3629876/), or almost 2.3*10^17 protons per 10 mL sample used in the study I linked to.
Obviously you're not going to be able to taste a single proton in your mouth. But maybe only a very small fraction of those protons are actually interacting with the receptors. Figuring out the threshold on the cellular level would be complex because it would depend on the rate of diffusion of H+ through the relevant channels and the number of relevant channels.
Re: Can a Human See a Single Photon? (1996)
#18Earlier quoted context omitted.
Not 1 but 5-9 photons, still less than billions :) pretty amazing
It’s cool our brains have that as a heuristic for whatever reason. Wonder if you could train yourself to see 1-3?
If you tune up your sensitivity to 1-3 photons, you'll probably find a maddening TV white noise overlaid on your vision.
Re: Can a Human See a Single Photon? (1996)
#19I’ve been aware of this fact as Feynman points it out in the course of the lectures, but find it totally nuts — there is some sense of scale I’m missing. Matter consists of discrete chunks, atoms, but these chunks are so infinitesimal and numerous that there is no question of seeing them and any effect involving a handful of them is far, far below the human scale. Light also comes in chunks, and the number of these c…
The visible photons have enough energy above the room temperature noise, that each one can be detected and amplified. Even when that energy is minuscule, it is sufficient to affect a molecule of pigment enough to cause cascade of amplifying reactions leading to detection.
Re: Can a Human See a Single Photon? (1996)
#20What is the comparison to modern camera sensors nowadays? Can they detect single photons?