How is the quantum nature of the observation process reconciled with classical physics?
When astronomers take time exposure photographs of distant galaxies and stars, or when x-ray astronomers study distant x-ray sources, they frequently end up detecting individual photons of light striking their photographic plates or detectors. To build up an image of an object, you need several thousand of these individual quantum events. The photographic plate accumulates these individual photons in the emulsion by chemically changing the emulsion each time a photon collides with the film. Other detectors have outputs that have to be summed electronically over a set integration time prescribed by the observer. There is no problem reconciling the quantum nature of this detection process with the classical nature of the objects being studied. The human eye and brain can discern as few as 1 or 2 photons, but to build up an image of what you are seeing you need light levels 100 – 1000 times brighter because the eye cannot sum-up and remember photons that arrived at the retina more than a
