Comment by rolph
2 years ago
a proton, in the simplist version, is made of 3 quarks. two up quarks one down quark.
down qwark is -1/3 e ; up quark is +2/3 e.
they sum up to +1 e.
neutrons are the opposite made of 3 quarks. two down quarks one up quark. and sum to 0e
the unitary quantity is a conveinience.
1 e = 1.602176634×10−19 coulombs,
Yes, yes, I also understand this.
But why are they in units of 1/3(e).
Why are down quarks not -0.398390847895...(e) and up quarks not +0.6234098129034809234...(e). Why do they add up so damn neatly?
https://en.m.wikipedia.org/wiki/Mathematical_formulation_of_...
Mathematically it works out that way because the standard model is build up from symmetry groups. The hand wavy explanation is that the symmetries observed in nature wouldn't be reproduced if the charges differed by random irrational numbers.
The same is also generally true of other conserved quantities in the SM. Noether's theorem unifies symmetries and conservation laws as the same thing.
As far as a more fundamental explanation as to WHY the universe is this way, ask your god i guess.
Could be a bit of anthropic principle at play. Universes where things don't work out with some stability might not support chemistry, and biology is especially finicky chemistry.
Because they are mathematical models built to describe a thing and thus their entire purpose as a concept is to add up “neatly”
No. These are not numbers physicists just pulled out of their asses. You act like the mathematical model could have been anything else. That's not just wrong, but decidedly anti-science.
We can test your theory: if the entire purpose of the mathematical model was to "add up neatly", and that's the reason why charge(proton) / charge(electron) is a nice round -1, then that should be true for other properties, right? What is mass(proton) / mass(electron)? It's 1836.1526734... Is that nice and neat? No, it's not. And yet physicists didn't decide to adjust their theory because that number offended them, as you suggest. Turns out you're spreading anti-science disinformation for absolutely no reason.
The purpose of the theory is to describe reality. In the case of charge, it is reality that adds up "neatly".
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No, these are models with simple, testable properties. You can't wave away the fundamental charges as something somebody made up to make the models nice, conspiracy theories don't work when there is a simply observable truth.
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I'm getting very strong "angels on a pinhead" vibes from this
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My layman understanding is that charge is not fundamental. It derives from something called weak hypercharge.
https://en.wikipedia.org/wiki/Weak_hypercharge
Because that is the universe we live in. We don't know where the universal constants come from, if they are random, or selected. Science can't really answer the question of "why", it only does "how".
You're effectively asking why universal constants are the value that they are. Eventually there's no answer other than "it's a property of the universe we live in that we observed."
If you keep asking why eventually you'll reach a ratio between two values: constants and you can't really go further deeper than that. Even if the values we have now end up not being the most fundamental, eventually you'll run into the fundamental ones and still have the same question unanswered.
It’s essentially asking why is the speed of light 299,798,452 m/s or the gravitational constant 6.67x10-11 Nm2/kg2
I’m sure a universe could work with those constants varied but that’s the one we have in our universe.
There could be hypothetical universes with protons being half of electron and atoms would have twice the protons.
However the fundamental constants are just that. A number that allows us to reason about how the universe works.
As to why the number is that, gotta ask your God why they chose that specific value.
The first thing to point out here is that the
> the speed of light
is not
> 299,798,452 m/s
It is quite inaccurate to say this. The correct way to phrase this is that the speed of light is 1/sqrt(permeability * permittivity) of the medium through which the light is traveling.
For a perfect vacuum, these two properties of that vacuum give a result as specified above. For other specified medium, you will get a different value, which could be greater than or less than the above figure.
Little technicalities matter in such cases, as it opens up the discussion. Part of that discussion is that solar space or interstellar space or intergalactic space will have distributions of matter that can alter what the speed of light is away from the assumed perfect vacuum speed of light.
Simple assumptions such as perfect vacuum are quite likely to affect how accurate our models of the universe are. The problem for us is that we are here and not out there making actual on location measurements of the permittivity and permeability of the relevant regions. The assumptions made in our models can come back and bite us in the long term.
Now as for the models we use currently for proton and neutron structure, there are assumptions here that could well be misleading us even though our models appear to work. There are alternate models available (since at least the early 20th century) which have, as far as I know, not been investigated with any detailed effort. Now, of course, it doesn't mean that these alternatives are actually viable, but we don't really know at this time.
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> It’s essentially asking why is the speed of light 299,798,452 m/s or the gravitational constant 6.67x10-11 Nm2/kg2
No, because those constants are entirely arbitrary.
The curiosity here is that you have multiple numbers lining up, only separated by small integers.
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Or, there's some more fundamental rule that's being followed that we haven't discovered yet that explains these numbers.
Physicists have been searching for the Grand Unified Theory since forever, and so far, no real luck. The closest is something i'm not too familiar with called M-theory (which is a derivative(?) of string theory).
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Ok probably a dumb take but: doesn’t that “stable forms become more common over time” principle also apply to protons purely by principle of them being in opposition to electrons? Ie the field that coalesces into the quarks we see today because those quarks can ultimately form atoms.
EDIT: after reading the great Wikipedia article above, and a connected one [1], I think I can restate: the only place we can look for these particles is in atoms, so it shouldn’t surprise us that they come in convenient forms to support atom formation.
[1] https://en.wikipedia.org/wiki/Accidental_symmetry
when you understand quantum theory correctly, you will realize that particles don't exist by themselves. They are a temporary localization. this means that the number of quarks inside a proton is not actually fixed. when a particle becomes disentangled with the system, that localized it, there's no longer a particle
I mentioned this recently, in the context of the laziness in language, leading to the miseducation of those who don't know better, and was heavily downvoted and ridiculed
keep it up, hn, you'll see idiocracy soon enough and then no one will trigger you
I was ready to up vote until the third paragraph.
Reading your other comments down thread doesn't paint you in a good light. Maybe your argument about laziness in language wasn't as cogent as you thought. Maybe you aren't as good at presenting arguments as you thought.
In other words, maybe you need some humility.
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HN is a great training ground for learning how to present arguments in a compelling, engaging manner.
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So far as I can tell, the fact that
"particles" are just what we call particular kinds of excitations in quantum fields
doesn't in any way answer, or obviate, or otherwise demystify the question of
why the electric charge associated with one sort of "particle" should be exactly 3x the electric charge associated with another.
So your comment is not only gratuitously rude, it's also either (1) wrong or (2) missing some essential explanation.
What do you mean by "temporary localization"? That protons move? That they can poof? They dont seem to self destruct.
On a side note: are there any models that assume that there are fields/shapes that are constanly bombarbed by neutrinos and other stuff. Thks bombardment seems to be always ignored
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thanks, i want to stress the model of the proton i had posited up thread is very simplified, for the purpose of explanation.
>the unitary quantity is a conveinience.
Ah right, so basically its just a convenience notation? We could as well say that proton has 3 and electron is -3 charge?
> We could as well say that proton has 3 and electron is -3 charge?
Absolutely! In fact that would have been much more convenient, since the "quantum of charge" appears to be 1/3 of the charge of the proton. All units of charge we've ever observed seem to be integer multiples of 1/3e.
Yes, individual dimensioned quantities are arbitrary: only the relationships between them have physical meaning.
> a proton, in the simplist version, is made of 3 quarks. two up quarks one down quark.
OP's article has a full paragraph dedicated saying that "The proton is much more than three quarks"
How does 2/3 - 1/3 not sum to 1/3? 2-1 is 1, right? What am I missing?
2 up quarks, so 2/3 * 2 -> 4/3. And then 4/3 - 1/3 = 3/3 = 1
Ah ha, I thought it was 1/3 per quark. Thanks.
Thanks I wondered the same