What prevents two protons from combining?

Answer 1

the electromagnetic repulsion.

they are both positively charged particles, and just like putting the south ends of a magnet together, they are actually repelled.

what stops them from flying apart is the strong nuclear force. gravity is also an attractive force between them yet it is so weak that it is negligible when being compared to the electromagnetic repulsion.

Answer 2

The strong atomic force, an attractive force, also called binding energy, is 100 times more powerful than the electromagnetic force, an attractive/repulsive force, depending on charge, at the distance involving the proton.

Answer 3

Both protons will be positively charged, and will repel each other because they have the same type of charge. If they travel fast enough, they do collide, and fuse, and one of the protons will emit a positron and a neutrino, and become a neutron. Add an electron to the mix, and you get deuterium, a heavier isotope of hydrogen. A Deuterium nucleus may then fuse with another one to form a helium nucleus. It's difficult to make the protons fuse because they need to fly towards each other at high speeds to be able to actually collide, which means heating it up to very high temperatures. Temperatures no alloy in the world can withstand. That's why nuclear fusion isn't quite ready yet. Scientists are trying to suspend these particles with magnetic fields, to make sure nothing touches the insanely hot plasma, but this is difficult, and that's why it's taking so long to make a cleaner, greener tomorrow.

Answer 4

The nuclear force (a manifestation of the strong interaction, one of the four forces of modern physical theory) binds the nucleons together. It's a common misconception that just the neutrons hold the nucleus together; the binding effect of the nuclear force which prevents the protons from flying apart is felt by both neutrons and protons.