Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Inside the proton, the ‘most complicated thing you could possibly imagine’

quantamagazine.org

Post reply on HN
Print view View original

461–470 of 591 posts

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#461

Post by gpsx »

andy_xor_andrew wrote: post #18

I just had a really stupid thought, after finishing reading the article. So, the electron is an elementary particle, right? Compared to the proton, the electron is "simple", yes? Despite this difference in complexity, an electron has a charge of -e and a proton has a charge of +e. They are exactly complementary regarding charge (if I am understanding right, I am not a smart person). my question is... why? why must pr…

In a "grand unified theory" (which does not include gravity) the strong, electromagnetic and weak forces are unified into one gague theory. SU(5) is one choice. In these theories, the electron, quark and neurtinos fit together as if they were different versions of the same particle, just as in the standard model the up quark has three "colors". In these theories there is a well defined relation between the charges. You can lookup the SU(5) unified theory to see more. I would say these theories are widely believed, but we have not managed to put them all together yet.

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#462

Post by kamaal »

plussed_reader wrote: post #449
kamaal wrote: post #437

Earlier quoted context omitted.

Thats interesting, what are the chances of another big bang, after our(the current one) big bang? Could it happen while this universe is here?

I recently came into the concept of the great attractor; the mysterious force that our galaxy is hurtling towards. It is thought to be some supermass of star material and other things. What if that supermass is another(the next?) big bang forming; energy just slides around some universe space banging off here and there, forever?

I don't know much about this of this of course.

But it does feel like you might have a point here. If everything is moving away from each other, things must have a center some where, and thats where this new big bang is forming?

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#463

Post by roelschroeven »

s1artibartfast wrote: post #455
jodrellblank wrote: post #252

Earlier quoted context omitted.

Not sure, but Protons are ~1800x more massive than electrons even though they have the same electric charge, so it seems like they would need 1800x more energy to move them. Power in an electric circuit is Watts, which is current in Amperes times voltage. Amperes are one Coulomb or 6.241509x10^18 electric charges per second flowing through a conductor. So a fixed amount of power (Watts) moves a known amount of charge…

Electric Power isn't like a pipe and water wheel where you need a net flow of electrons. The work is done by the electric field, which is why we can have AC power where electrons don't have any net travel. This also is why electric power flows along a wire at the speed of light, while electrons can only travel along a wire at the speed of a snail, or about 1 mm per second

> The work is done by the electric field, which is why we can have AC power where electrons don't have any net travel.

One doesn't follow from the other. We can easily transport power by making things like a chain or a fluid move back and forth, without any net travel. In a setup with a loudspeaker and a microphone as just one example the air transfers energy from one to the other without any net movement. In those cases it's clearly the movement itself which transfers the energy. Therefore energy transport by AC is no proof for the need of an electric field for energy transport.

That's not say to there is no electric field, or to deny its role in power transfer. There certainly is an electric field. But that field is intimately tied to the electrons in the conductor, and power transfer is intimately tied to movement of those electrons and the way electrons repel each other stronger when they get closer together (or other charge carriers, but in typical conductors that means electrons). You can't have one without the other.

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#464

Post by l33tman »

dcow wrote: post #331

“The proton is a quantum mechanical object that exists as a haze of probabilities until an experiment forces it to take a concrete form.” I’m getting really tired of hazy probability distributions and waves that only collapse and materialize when observed. I 100% accept that QM is a useful tool to model our current understanding based on increasingly sophisticated observations, but I fundamentally don’t believe that…

QFT is the most well-tested physics theory mankind has developed and certainly is not a "haze" as the pop-sci articles write.

What they mean by the "haze of probabilities" is that you need to iterate over all possible configurations of the gluons and quarks in the proton to produce experimental predictions.

It is for sure computationally ludicrous, but conceptually it's really not better or worse than to say that particles are billiard balls moving around by Newton's Equations. You're just more used to the latter, but spend some time working with for example Lattice QCD and you get completely used to the former being the "actual" underlying physics rules.

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#465

Post by l33tman »

roelschroeven wrote: post #459
dcow wrote: post #331

“The proton is a quantum mechanical object that exists as a haze of probabilities until an experiment forces it to take a concrete form.” I’m getting really tired of hazy probability distributions and waves that only collapse and materialize when observed. I 100% accept that QM is a useful tool to model our current understanding based on increasingly sophisticated observations, but I fundamentally don’t believe that…

In my understanding a wave function doesn't collapse just when someone observes it; it collapses when it participates in any physical event. "I fundamentally don’t believe that a proton is some shape shifting quantum soup of energy that doesn't form until someone comes around and thinks about it." is the way quantum mechanics is often portrayed in pop sci, but it simply can't be true. Quantum mechanics existed just f…

It reflects the fact that the measurement apparatus, environment in general and the observer in particular are all also part of the "wave function". Until these are linked to the system to be observed (like the proton), the system has to be analyzed as the full set of possible configurations of its constituents.

After you link it up with the apparatus, it is pulled into the system as a new part of it, and so on. The more stuff you pull into the system, the less number of different configurations you sum over, eventually you end up with a single configuration with an observer that has a clear measurement result in her mind. This process is what is called "wavefunction collapse" in old physics texts (and a lot of modern pop-sci accounts).

What sets this apart from other purely probabilistic theories is that it's non-local, the entire linked system from the proton to the measurement apparatus to the observer has to be taken into account in the calculations if you are to be thorough. In local theories you can separate the parts of the system and handle them separately, like you could say "there is a 1% probability that a charm quark pops out in the upper left part of the proton every second" etc. You can't really do this in QM/QFT, and this is what in essence leads to all of the counter-intuitive results and confusion..

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#466

Post by alok-g »

ronald_raygun wrote: post #418
Rayhem wrote: post #54

Earlier quoted context omitted.

> I have no doubt quantum physicists know what they are talking about but...I always think it is the kind of excuse a schoolkid would give their teachers for their calculations being wrong. Just to emphasize how extreme this dichotomy is, not only is quantum mechanics correct (in that it's a predictive model), it's the most correct physical theory humans have ever devised in that the measurements there have more sign…

Just because it’s quantitatively accurate doesn’t mean it’s “true”. Like a fun fact I like is the geocentrism was extremely accurate in terms of astronomical predictions when heliocentricism came about (it was actually more accurate for a while).

How do you define 'true'?

If two theories are working very well with no experiment available to indicate right vs. wrong for them, Occam's Razor would be all we would have to make a choice. That however does not really make one of them truer than the other.

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#467

Post by geye1234 »

notahacker wrote: post #142
jononomo wrote: post #67

Earlier quoted context omitted.

> the more we learn, the more we realize how much we don't know This is why the "god of the gaps" critique is so short-sighted. It relies on the assumption that as science progresses it will "close the gaps". In reality the opposite happens. Another example is the cell -- in Darwin's day it was thought to be a simple thing, but then we learned more about it and it turned out to be monstrously complex and the mystery…

Nope, the "god of the gaps" critique has nothing to do scientific discovery being a route to omniscience, something only some religious figures have ever claimed to have even the possibility of access to. It's the set of things religions claim the only explanation/evidence for repeatedly shrinking, as we found explanations for weather that have more predictive power than "the wrath/favour of the gods", found cures fo…

> Nope, the "god of the gaps" critique has nothing to do scientific discovery being a route to omniscience, something only some religious figures have ever claimed to have even the possibility of access to. It's the set of things religions claim the only explanation/evidence for repeatedly shrinking, as we found [scientific] explanations...

The 'god of the gaps' argument, which is pushed very hard by the new atheists[0], is question-begging and therefore worthless. The assumption is that if something is going to be explained at all, it must be via scientific methods. Therefore (they say) the appeal to God should be seen as a poor hypothesis, comparable in kind to scientific hypotheses, but vastly less useful in terms of prediction.

The whole debate is about whether it's rational to think that the entirety of an explanation for something is scientific. Therefore, the 'god of the gaps' argument is circular and question-begging.

The good arguments for God's existence and attributes, which the new atheists ignore[1] or grossly straw-man, involve the most basic of observations (such as 'there is change' or 'there are objects of the same type'), followed by deductions from said observations. They're rational arguments, assuming they're successful, but they're not scientific hypotheses. They do not appeal to things we can't explain, nor to complexity, nor to any alleged design (the last phrase is misleading anyway).

[0] It's in Dawkins, Hitchens, Harris, I think Krauss too

[1] Dennett gives them one paragraph out of 478 pages in Breaking the Spell, and is guilty in this paragraph of a very common straw-man, which shows how little he's read. Dawkins also uses the same straw-man in God Delusion IIRC.

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#468

Post by geye1234 »

notahacker wrote: post #412
knightoffaith wrote: post #283

Earlier quoted context omitted.

>It's the set of things religions claim the only explanation/evidence for repeatedly shrinking I haven't read The God Delusion or wherever the "god of the gaps" critique originated - what is this actually referring to? Are we just talking about like, pagan polytheistic explanations of natural phenomena? What serious Christian or Buddhist thinkers using religion to explain things like weather or medicine are being ref…

> I haven't read The God Delusion or wherever the "god of the gaps" critique originated - what is this actually referring to? A rare point of agreement between Nietzsche and the evangelist Henry Drummond was that the Christian apologetic approach of "ah, but that hasn't been explained yet, so it must be God's will" to all the discoveries of the Enlightenment wasn't a very impressive one. Not least because of the tend…

> Augustine, since you're apparently a fan, was pretty confident that the problem of pestilence was the product of a literally occurring Fall involving two actual First People, which doesn't square very well with evolutionary biology.

My understanding is that the current hypothesis says we are, in fact, all descended from one couple. I could be wrong about that though.

In any case, there's no contradiction between Original Sin, and germs and immunity and the like, as explanations for disease. See my previous comment.

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#469

Post by amai »

andy_xor_andrew wrote: post #18

I just had a really stupid thought, after finishing reading the article. So, the electron is an elementary particle, right? Compared to the proton, the electron is "simple", yes? Despite this difference in complexity, an electron has a charge of -e and a proton has a charge of +e. They are exactly complementary regarding charge (if I am understanding right, I am not a smart person). my question is... why? why must pr…

A simple answer could be that there is an elementary charge. No free particle can have less than this charge and charges are quantized in terms of this elementary charge.

This is in opposition to e.g. mass. There is no elementary mass, and so no particles need to have the same mass.

Re: Inside the proton, the ‘most complicated thing you could possibly imagine’

#470

Post by lostemptations5 »

cgriswald wrote: post #454
lostemptations5 wrote: post #419

Earlier quoted context omitted.

"Since 2019 the metre has been defined as the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second, where the second is defined by a hyperfine transition frequency of caesium." ( https://en.m.wikipedia.org/wiki/Metre ) I wouldn't call it totally random, no. It's really derived from somethings real in this universe. > So, the precise numbers are only meaningful as part of a…

No. Some of you are talking past each other. The speed of light being exactly the number c is arbitrary, because the choice to use the ephemeris second as the base unit of time (regardless of the precision we get by now using cesium atom “beats”) is arbitrary even though it’s based on something real. That’s just standardizing our arbitrary choice. The charge of an electron is also effectively arbitrary for the same r…

OP: "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."

And so the post I responded too said these constants are totally RANDOM / ARBITRARY.

But they cannot be otherwise the universe wouldn't work (as far as we know).

The measurements or units we use to express these are arbitrary-- but the constants themselves are DERIVED from the system we call the universe. Without them the system wouldn't work.

Is this really so controversial?

Post reply on HN