The reason you don't fall apart or pass through objects is due to the fundamental forces and principles that govern the behavior of matter at the atomic and subatomic level. While there is indeed space between atoms, several factors prevent you from falling apart or easily passing through solid objects:
Electromagnetic forces: Atoms consist of a nucleus, made up of protons and neutrons, surrounded by a cloud of electrons. The negatively charged electrons repel each other due to electromagnetic forces, creating a repulsive barrier that prevents the atoms from collapsing into each other. This repulsion is what gives objects their solid structure and prevents them from passing through each other.
Pauli exclusion principle: According to this principle, no two fermions (such as electrons) can occupy the same quantum state simultaneously. This means that electrons in the outer shells of atoms cannot occupy the same space, preventing them from merging together. It is the repulsion between electron clouds that provides resistance and stops objects from collapsing.
Strong nuclear force: The nucleus of an atom is held together by the strong nuclear force, which is an incredibly powerful force but operates only at extremely short distances. This force keeps the protons and neutrons tightly bound within the nucleus, ensuring the overall stability of the atom.
Conservation of energy: Energy cannot be created or destroyed; it can only be transferred or transformed. When you try to pass through an object, the repulsive electromagnetic forces between the atoms in your body and the atoms in the object you're trying to pass through create a strong resistance. This resistance requires a significant amount of energy to overcome, making it practically impossible for you to pass through solid matter.
While atoms are mostly empty space, the forces and principles described above give matter its structure and stability, preventing you from falling apart or passing through objects.