It’s a statement that seems to defy common sense and everyday experience. Right this moment, you can feel the weight of your body on your chair, the texture of your clothes against your skin, or the cold touch of your phone’s screen beneath your fingertips. Your brain is sending you a clear message: “I am touching this object.” Yet, from a purely physical standpoint, it is a total illusion. At the atomic scale, true contact is an absolute impossibility. You are continually hovering a few nanometers away from everything around you.
The Vertiginous Void of Matter
To understand this paradox, one must dive into the heart of the structure of the atom. Contrary to what our senses reveal, matter is essentially made up of emptiness. If the nucleus of an atom were a ball placed at the center of a football stadium, the electrons would be tiny specks of dust whirling high up in the stands. All of the space between the nucleus and the electrons is empty.
But then, why don’t you pass through your chair? What prevents your fingers from passing through your phone is the electromagnetic interaction. Atoms are surrounded by a cloud of negatively charged electrons. In fundamental physics, like charges repel each other. When you bring your finger close to an object, the electrons of the atoms in your skin push back against those of the object with a titanic force that grows exponentially as the distance decreases.
The Pauli Exclusion Principle and the Repulsive Force
This invisible barrier is governed by a fundamental rule of quantum mechanics called the Pauli Exclusion Principle. This principle formally forbids two fermions (the matter particles such as electrons) from occupying the same quantum state at the same location and time. In short: matter is “stubborn”; it refuses to overlap.
What you interpret as a sensation of “touch” is therefore not a collision of solid matter against solid matter. It is, in fact, the experience of this repulsive force. Your nerves respond to the pressure of the electromagnetic field that pushes back against your own atoms. It’s akin to trying to push two very powerful magnets together with identical poles: you feel resistance, an invisible cushion of air that prevents contact.
As the Fermilab physics department explains very well, you never actually touch the object; you interact with its force field at an infinitesimal distance (about an angstrom, roughly 0.1 nanometer), but it is insurmountable. The only way to truly “touch” another atom would be to induce nuclear fusion, which, fortunately for your phone, does not occur in everyday life.
