In order for particles to interact, they do not necessarily have to be touching each other. Interactions between particles can occur through various forces, such as electromagnetic forces or gravitational forces, even if the particles are not in direct contact with each other. For example, two charged particles can interact through the electromagnetic force, causing them to be attracted or repelled from each other, without requiring physical contact. Similarly, particles can interact through the gravitational force, which can act over large distances. Therefore, while some interactions may involve touching, it is not a requirement for all particle interactions.
