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Is particle physics dead, dying, or just hard?

quantamagazine.org

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Re: Is particle physics dead, dying, or just hard?

#41

Post by libraryofbabel »

PaulHoule wrote: post #18
tasty_freeze wrote: post #15

Here is one fact that seems, to me, pretty convincing that there is another layer underneath what we know. The charge of electrons is -1 and protons +1. It has been experimentally measured out to 12 digits or so to be the same magnitude, just opposite charge. However, there are no theories why this is -- they are simply measured and that is it. It beggars belief that these just happen to be exactly (as far as we can…

If it wasn't the case then matter wouldn't be stable.

Is that actually true, if the charges differed at the 12th decimal place only? That’s non-obvious to me.

Re: Is particle physics dead, dying, or just hard?

#42

Post by light_triad »

klipt wrote: post #24
bananaflag wrote: post #7

It's basically the opposite situation from 150 years ago. Back then, we thought our theory was more or less complete while having experimental data which disproved it (Michelson-Morley experiment, Mercury perihelion, I am sure there are others). Right now, we know our theories are incomplete (since GR and QFT are incompatible) while having no experimental data which contradicts them.

Doesn't that imply our theories are "good enough" for all practical purposes? If they're impossible to empirically disprove?

There's still huge gaps in our understanding: quantum gravity, dark matter, what happens before planck time, thermodynamics of life and many others.

Part of the problem is that building bigger colliders, telescopes, and gravitational wave detectors requires huge resources and very powerful computers to store and crunch all the data.

We're cutting research instead of funding it right now and sending our brightest researchers to Europe and China...

Re: Is particle physics dead, dying, or just hard?

#43

Post by idiotsecant »

klipt wrote: post #24
bananaflag wrote: post #7

It's basically the opposite situation from 150 years ago. Back then, we thought our theory was more or less complete while having experimental data which disproved it (Michelson-Morley experiment, Mercury perihelion, I am sure there are others). Right now, we know our theories are incomplete (since GR and QFT are incompatible) while having no experimental data which contradicts them.

Doesn't that imply our theories are "good enough" for all practical purposes? If they're impossible to empirically disprove?

Absolutely not. Newtonian physics was 'good enough' until we disproved it. Imagine where we would be if all we had was Newtonian physics.

Re: Is particle physics dead, dying, or just hard?

#44

Post by smnplk »

tasty_freeze wrote: post #15

Here is one fact that seems, to me, pretty convincing that there is another layer underneath what we know. The charge of electrons is -1 and protons +1. It has been experimentally measured out to 12 digits or so to be the same magnitude, just opposite charge. However, there are no theories why this is -- they are simply measured and that is it. It beggars belief that these just happen to be exactly (as far as we can…

There are layers science can not access.

Re: Is particle physics dead, dying, or just hard?

#45

Post by Legend2440 »

klipt wrote: post #24
bananaflag wrote: post #7

It's basically the opposite situation from 150 years ago. Back then, we thought our theory was more or less complete while having experimental data which disproved it (Michelson-Morley experiment, Mercury perihelion, I am sure there are others). Right now, we know our theories are incomplete (since GR and QFT are incompatible) while having no experimental data which contradicts them.

Doesn't that imply our theories are "good enough" for all practical purposes? If they're impossible to empirically disprove?

Typically whenever you look closely at an object with complex behavior, there is a system inside made of smaller, simpler objects interacting to produce the complexity.

You'd expect that at the bottom, the smallest objects would be extremely simple and would follow some single physical law.

But the smallest objects we know of still have pretty complex behavior! So there's probably another layer underneath that we don't know about yet, maybe more than one.

Re: Is particle physics dead, dying, or just hard?

#46

Post by ggm »

I am sure others will say it better, but the cat-in-the-box experiment is a shockingly bad metaphor for the idea behind quantum states and observer effect.

I will commit the first sin, by declaring without fear of contradiction the cat actually IS either alive or dead. it is not in a superposition of states. What is unknown is our knowledge of the state, and what collapses is that uncertainty.

If you shift this to the particle, not the cat, what changes? because if very much changes, my first comment about the unsuitability of the metaphor is upheld, and if very little changes, my comment has been disproven.

It would be clear I am neither a physicist nor a logician.

Re: Is particle physics dead, dying, or just hard?

#47

Post by csomar »

klipt wrote: post #24
bananaflag wrote: post #7

It's basically the opposite situation from 150 years ago. Back then, we thought our theory was more or less complete while having experimental data which disproved it (Michelson-Morley experiment, Mercury perihelion, I am sure there are others). Right now, we know our theories are incomplete (since GR and QFT are incompatible) while having no experimental data which contradicts them.

Doesn't that imply our theories are "good enough" for all practical purposes? If they're impossible to empirically disprove?

I think the problem is that GR and QFT are at odds with each other? (I am not quite versed in the subject and this is my high-level understanding of the “problem”)

Re: Is particle physics dead, dying, or just hard?

#48

Post by tasty_freeze »

Paracompact wrote: post #21
tasty_freeze wrote: post #15

Here is one fact that seems, to me, pretty convincing that there is another layer underneath what we know. The charge of electrons is -1 and protons +1. It has been experimentally measured out to 12 digits or so to be the same magnitude, just opposite charge. However, there are no theories why this is -- they are simply measured and that is it. It beggars belief that these just happen to be exactly (as far as we can…

Technically, the charge of a proton can be derived from its constituent 2 up quarks and 1 down quark, which have charges 2/3 and -1/3 respectively. I'm not aware of any deeper reason why these should be simple fractional ratios of the charge of the electron, however, I'm not sure there needs to be one. If you believe the stack of turtles ends somewhere, you have to accept there will eventually be (hopefully simple) c…

I'm aware of the charge coming from quarks, but my point remains.

> you have to accept there will eventually be (hopefully simple) coincidences between certain fundamental values, no?

When the probability of coincidence is epsilon, then, no. Right now they are the same to 12 digits, but that undersells it, because that is just the trailing digits. There is nothing which says the leading digits must be the same, eg, one could be 10^30 times bigger than the other. Are you still going to just shrug and say "coincidence?"

That there are 26 fundamental constants and this one is just exactly the same is untenable.

Re: Is particle physics dead, dying, or just hard?

#49

Post by idiotsecant »

Paracompact wrote: post #21
tasty_freeze wrote: post #15

Here is one fact that seems, to me, pretty convincing that there is another layer underneath what we know. The charge of electrons is -1 and protons +1. It has been experimentally measured out to 12 digits or so to be the same magnitude, just opposite charge. However, there are no theories why this is -- they are simply measured and that is it. It beggars belief that these just happen to be exactly (as far as we can…

Technically, the charge of a proton can be derived from its constituent 2 up quarks and 1 down quark, which have charges 2/3 and -1/3 respectively. I'm not aware of any deeper reason why these should be simple fractional ratios of the charge of the electron, however, I'm not sure there needs to be one. If you believe the stack of turtles ends somewhere, you have to accept there will eventually be (hopefully simple) c…

Shrugging and calling it a coincidence is generally not an end state when figuring out how something works.
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