If atoms, blocks of construction of the subject, are mostly empty space, why cannot we cross walls? Two principles of physics explain.
In movies, like Harry Potter, crossing a wall looks very natural. But in the real world, trying these tricks would leave us with nose problems.
In an article, experts explain the two concepts of physics that make it impossible to walk through solid materials: electromagnetic repulsion and the principle of exclusion of Pauli.
An atom has a nucleus, which is made of protons and neutrons, and electrons that move around it. The positive charge of the protons and the negative charge of the electrons pull each other, keeping the atom together.
But in quantum mechanics, the electron does not move in a tidy circle. Instead, it forms a cloud species – a diffuse area where it may be. This is called “a cloud of probability”, explains Raheem hashmaniPhD student in Physics at the University of Wisconsin-Madison.
This cloud does not move. It just stays there, showing the places where the electron is most likely to be found.
The cloud makes the ends of the atom charged negatively. “If I try to walk through a wall, the atoms on my body will see those on the wall, and they will repel each other“, Said, in turn, the physicist at the University of Maryland, Steven Rolston.
This is called electromagnetic repulsion – As when trying to push the same poles as two ie together. When walking through a wall, the electrons are interacting through electromagnetic waves. These waves are part of the forces that prevent atoms from overlapping and why solid matter remains and seems solid.
What if the atoms were pushed even closer to each other? That’s where the Principle of Exclusion of Pauli. He states that certain particles, called fermions, cannot share the same state of energy or be in the same place at the same time. Electrons are fermions, so in this case, the terms are interchangeable.
“When these electrons clouds begin to approach each other, they overlap, which means that two electrons could be sharing the same physical space. According to Pauli’s principle of exclusion, this is not allowed,” Hashmani explained.
Both concepts – the principle of exclusion of Pauli and the electromagnetic repulsion – prevent atoms from occupying the same space.
Without them, solid matter as we know it would not maintain its form. In liquids and gases, atoms are more free to move, but the same rules still apply. They just prevent atoms from overlapping, not moving.
Although almost 100% impossible objects pass through each other, quantum mechanics offers another perspective, stressing that, technically, there is a tiny hypothesis that this can happen. But don’t try to do it at home. Be careful with the nose.
