One problem seems to arise because of the switch between treating light as waves, and treating it as particles.

Let’s start with a star. It is a sphere which emits light in every direction. Looked at, at any point in space or time, the light progresses as a sphere. This is a reasonable wave model of light.

Sometimes there seems to be a tendency to consider a photon as though it were actually a sphere and could be observed from any angle. Such cannot be the case. A single photon would not radiate light; in fact, a single photon could not be observed until it was absorbed, after which it would no longer be a photon, or even light.

To complicate the matter further we cannot say that any travelling light is in any way particulate. It travels as a wave. This seems to be the cause of some confusion in that it is easy to slip into the “spherical radiation” image as soon as waves become significant. However, where light is emitted directionally the spherical radiation is not an appropriate model, however many photons might eventually be observed.

Popular science authors do not help with this issue when they talk about emitting light “one photon at a time”, because this suggests that the light travels as a particle.

It is tempting to progress to other aspects of the wave/particle duality, but these are the rambling thoughts of a “hitch-hiker” trying, one faltering step at a time, to make sense of reality, whatever that might be.


There never was nothing.