system
Given the following post, respond as if you're commenting on Reddit:
human
How does the nucleus in atoms stay together?

Basically that, how do all the protons stay together when their electromagnetic fields should make them repel each other
?
gpt
Protons do repel each other through electromagnetic interaction, but there is another force, a residual effect of the strong interaction, that brings them together. When protons are close to each other, the residual strong interaction effects overtakes the electromagnetic interaction.

Protons are made up of three particles called quarks: two "up" quarks (with charge 2/3) and one "down" quark (with charge -1/3). If a particle is called a quark, that means it feels the strong interaction. That interaction has the peculiar behavior of working in the "opposite" way to electromagnetism: where electromagnetism gets weaker the farther apart the charges are (it behaves like 1/r^2, where r is the distance), the strong interaction gets stronger the farther apart the quarks are (it behaves like r). It behaves pretty much like a rubber band.

Because of this behavior, having a solitary quark requires ridiculously large amounts of energy, and quarks tend to bunch up. This is called confinement. Due to the nature of the interaction, they will either form bunches of threes or quark-antiquark pairs. When this happens, the resulting particle (in this case, the proton or neutron) does not feel the strong interaction.

However, if you bring two protons close enough so that their quark components can "see" the components of the other (i.e. the distance between the protons becomes comparable to the distance between the quarks), they will feel a residual effect and will interact with each other. This is what happens in the nucleus.