[Lurker]

“but only because friction slows atoms down as they clumps together, rather than flying past one another.“

You sure about that?

L

[Telepathic Intruder]

Yes. It is the electromagnetic force which causes atoms to interact in the first place. When you slam two bricks together, they don't just pass through one another because the atoms are repelling one another through the electrostatic force of electrons. Things like neutrinos have no electromagnetic force, so they're not affected. You have trillions of them flying through your body every second and you don't even notice them. Are they real? Yes, we can detect them only through the weak nuclear force in neutrino detectors.

By the way, I'm leaving out the Pauli Exclusion Principal because it just adds another layer of complexity. But that's the reason why matter also resists clumping instead of everything collapsing into a black hole.