# Physics lecture: Universe could wink out of existence

By | March 17, 2014

During a 7 mile hike around Mt. Diablo today, I was asked why, if atoms are 99.9% empty space, things seem solid.

The best answer I could give is that there are two classes of all particles, bosons which can move through each other and fermions which can’t, due to the Pauli Exclusion Principle.

Fermions are the constituents of matter: electrons, protons, neutrons; while bosons are particles that transmit interactions (force carriers), or the constituents of radiation: Photons, the force carriers of the electromagnetic field, W and Z bosons, the force carriers that mediate the weak force and gluons the force carriers underlying the strong force.

This is not an answer, of course. It merely says that we have observed and named minute details of reality.

You might say that it would require infinite energy for two fermions to be in the same place at the same time. Why? Because that’s the nature of fermions.

Clear as mud?

Oh, and if the universe winks out, it will be at the speed of light. You probably won’t feel a thing.

## One thought on “Physics lecture: Universe could wink out of existence”

1. dakliegg

I answer that question by saying its not empty space. That idea of empty space comes from the analogy of atomic level geometries as tiny billiard balls. We don’t really know that. What we do know is that if we accelerate elections at solid matter some of them deflect more than others. The analogy used is that the space between the nuclei is denser in the middle, but that’s only because launching streams of electrons make it seem that way. As an alternative, think of the deflection as a probability that rises closer to the center of a nucleus you get. You can still get massive deflection at the edge, but only sometimes. Your more likely to get deflection in the center. Solidity stops being a discrete measure of some dimension, but a continuous function that falls off the farther from the center of the forces you get.

Bosons, fermions, and electrons are abstractions that make it easier to describe small scale high speed behaviors of matter and energy. But at that speed and scale, they are always soft with probabilities that seem more like cotton balls. At the macro scale things are solid because of the forces that tie things together in aggregate, and we see these things with the waves of energy that get transferred from distant objects to the atoms in our retinas.