"Cecil Moore" wrote
...
On Oct 18, 2:44 am, "Szczepan Bialek" wrote:
Photons are the math joke.

:-) ... he says as photons impacting his retina allow him to read the
postings and see his keyboard.

Light is not coherent. It is "produced" in the packets (photons). But the
radio waves and the radiation from the "free electron laser" are coherent.
When the photons start and when finish?
S*