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I was visualizing particle interactions one night and I realized I didn't know what color the particles actually are. I did a little research, but the search results were dominated by the color charge of the particles, which actually doesn't have anything to do with the color.

I understand that color is the specific energies of the light rays as they rebound from objects, and I guess it doesn't make sense for light rays to rebound off of elementary particles, but I also can't make sense of something not possessing a color.

Long story short, if you were able to "zoom in" far enough to see the elementary particles, what color would they be? And if they don't have a color, what would they look like?

Thank you

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  • $\begingroup$ For starters, the size of elementary particles are much smaller than the wavelength of visible light... $\endgroup$ – Qmechanic Apr 6 '18 at 16:36
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    $\begingroup$ I'm sure this has been asked before ... $\endgroup$ – John Rennie Apr 6 '18 at 17:09
  • $\begingroup$ Why the downvotes? I'm not sure what I did wrong $\endgroup$ – Mike H Apr 6 '18 at 23:28
  • $\begingroup$ Just for clarity: within a theory called quantum chromodynamics (a part of the Standard Model of particle physics), particles (notably quarks and gluons, but not protons, neutrons, or electrons) can have something called color charge. This is just an evocative way to use language to describe an abstract concept, and it has nothing to do with color as perceived by the human eye. $\endgroup$ – Emilio Pisanty Apr 9 '18 at 17:52
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if you were able to "zoom in" far enough to see the elementary particles, what color would they be ?

They have no intrinsic color. Color is a result of photons that your eye detects and to "see" an object it has to radiate or reflect light.

It's complicated but to "see" something photons have to interact with the thing you're seeing. There's no single way that happens for an elementary particle and hence no one appearance for any particular particle.

When you see everyday colors they are almost all due to the absorption and emission of photons when an electron changes energy level in an atom. But while electrons are elementary particles, the energy levels and their differences are a property of the atom as a whole, not the electron itself. The electron has no color itself.

And if they don't have a color, what would they look like?

What they would look like is a bit meaningless in relation to an elementary particle. You cannot even localize the position of an elementary particles (the uncertainty principle at work) and so it has no definite position, let alone a definite color.

There's another issue. In quantum theory when you observe something (make any measurement or interact with it at all) you change it's state. So even if you observe a photon after it has interacted with an electron, the electron itself could be in any state (again, the uncertainty principle working).

So there is no color and no meaningful human way to describe what an elementary particle looks like.

Which is why we use quantum theory to describe the behavior and properties of these things : nothing else makes sense except the mathematics.

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