The mutant superheroine of the Marvel universe, Kitty ( ShadowCat ) has the ability to “phase” that allows her to become intangible (and, therefore, to be able to pass through walls). But why can’t we – ordinary mortals – do the same?
Our body, like all ordinary matter in the universe for the most part, is made of atoms of varying amounts and types. Atoms are, in essence, a large empty space, since 99.9% of the mass of the atom resides inside the nucleus . So, taking into account that electrons only contribute 0.1%, it would seem plausible that being essentially empty space, we could pass through walls. Not?
For the fact that the nucleus of the atom is so heavy is the key: We are solid enough that the elements in our atoms cannot pass through the empty spaces of other atoms, and vice versa. So the intangibility of Shadowcat is going to have to remain part of the fiction.
It all has to do with the electrons that orbit the nucleus of an atom. Drawings of atoms show electrons ‘buzzing’ around a nucleus in a nice neat pattern, but that’s not the case at all – they sort of swarm around it in something that looks more like a cluster of clouds.
To pass through another atom – and get through objects – the electrons of the first atom would have to exist, even briefly, in the same atomic space as the electrons of the second atom. And, simply put, this is impossible.
As first formulated by Austrian physicist Wolfgang Pauli in 1925, there cannot be two fermions in the same quantum state within the same quantum system. That is, there cannot be two electrons occupying the same space doing the same work. It happens like the mythical movie “The Immortals”, there can only be one left . This is what we know as the Pauli Exclusion Principle and it applies to all fermions. It also means that the atoms are quite effective in preventing other atoms from entering their space.
This is what makes solid objects solid and prevents them from passing into each other.
Does that mean they can never be touched? Let’s say it’s complicated.
In quantum mechanics this is sometimes explained as a repulsive force between the two fermions, and the popular interpretation of science is that this prevents atoms from touching other atoms. But the way the word “force” is used to describe these interactions does not translate into the way the word is used in the world at large.
According to research published in 2003 in the American Journal of Physics (published in its entirety in arXiv ), the word “force” is a poor analogy that has the potential to be misinterpreted by all of us, but not yet. we have a better one.
Fuerzas de van der Waals
According to Philip Moriarty, professor of physics at the University of Nottingham (England) , “contact” exists at the atomic level: it is the point at which the attractive Van der Waals force (a type of intermolecular force that is created between molecules that makes that can generate attraction or repulsion and that allow substances to have different physical properties such as boiling point or density), balances the Pauli repulsion factor. But that is not necessarily the same as “touching”.
Referencia:Quantum Statistics: Is there an effective fermion repulsion or boson attraction? W. J. Mullin and G. Blaylock https://arxiv.org/pdf/physics/0304067.pdf
