Reply to Blue Crab on Young's double-slit "interference" experiment:
Elsewhere [moderators, do you know where this is? I can't find it since the accidental demolition of the previous forum], I explained a model for so-called "interference" and "diffraction" in which we see these patterns as a light field pressure gradient.
The image you referenced is a contortion of Young's actual finding in at least these ways:
1. The image's arrows are set up linearly, but in an accurate moire diagram of intersecting wavefronts, you will notice the "nodal" lines are actually hyperbolic [some might say hypercycloidal]. This was ignored by Young but anyone with a home-made double slit apparatus will be able to see clearly that these lines are in fact rectilinear, defying Young's wave explanation.
2. The alleged wavelengths of light are so close together that their interaction with the slit widths in the experiment would not match the diagramatic version.
3. Young's idea of interference was that the pattern was manifest only in the presence of a beam splitter. Moreover, the diagramatic explanation of wave interference requires the beamsplitter be coplanar with the slit edges, but the actual experiment, and many more you can try yourself, can be done with the beamsplitter in many planes or multiple planes, still yielding the same redundant spectral pattern. "Diffraction" has the same redundant spectra without a beamsplitter, although using a "correct" slit width is required to demonstrate this. Young undoubtedly must have seen this but concluded "interference" anyway.
4. The pattern is demonstrable using ONLY the beamsplitter! Take a long hair and place it in front of your pupil to observe any small light filament, such as the kind they put on Christmas strings, and
voila there's your pattern.
5. The pattern [at least half of it!] will show up along a single edge! This is also responsible for much of the light streaks you see through squinted eyelids, if you hadn't already noticed this, but a more distinct pattern is available with a little care in producing good light contrasted conditions.
6. Redundant spectra defy conventional EM explanation, whether in spectrographic settings or in rainbows and haloes. Mie theory or other mathematical attempts to describe "supernumeraries" are simply that, mathematical attempts to describe... offering little in the way of actual demonstration that light is physically waving anywhere.
In other posts of mine, you will see that I do not subscribe to a wave [nor a particle] theory of light, but to an understanding of light as a field pressure gradient phenomenon, acting instananeously across space, akin to voltage. I'll try to post more details later... as it is I do all this stuff while I'm trying to get work done.............................