Sunday, October 18, 2015

Optical Phenomena in the Land of Newton

I recently took a business trip to England. The home of Sir Isaac Newton, he of the famous prism experiments, the beginning of the science of optics. Our understanding of color begins with these experiments.

In his Opticks, Newton explained the colors of the rainbow. Like this one, a double bow, seen over the Newcastle airport.

It was in the cab ride from the office I was visiting to the hotel, right at the airport, that I first saw the bow. "Get your camera out," said the cabbie, "there's a gorgeous rainbow, a double bow." So I did.

And got the shot above of arches, natural and man made.

If you look closely at the shot above you can see the supernumeraries.

And in the shot below, taken form my hotel room, we see Alexander's Dark Band. Note the change in brightness from the inside to the outside of the main bow.

Newton may not have been able to explain all these rainbow phenomena. But he got us started. (And I'm sure he would have been fascinated by photography, especially the chemistry of film photography and the alchemy of the development process, turning silver into images.)

I've over-processed the image below, to make more obvious both the supernumeraries and the brightness contrast inside and outside the main bow.

Newton would have fully understood the explanation for he phenomena shown below.

The 22º halo. Ice crystals acting as prisms refracting the light (of the sun, not the lamp).

Often seen with the 22º halo, sundogs are another ice crystal phenomena.

Newton thought of light as particles and thus would have a hard time explaining the birefringence seen in the cockpit window of this airliner. (I had seen the linked OPOD and thus was on the lookout for this, and quick grabbed a shot as I boarded the plane.)

The colors are explained by the interference of light waves. Newton was half right so to speak, as today we think of light as both a particle and a wave. Although I have no idea what Sir Isaac would think of quantum mechanics.

And I'm not sure what Newton would have made of these next two images.

This is the Gateshead Millennium Bridge, over the River Tyne in Newcastle. The bridge tilts over to let ships pass, although not many ships come this far these days. And I didn't get to see it tilt.

Not being flat, the surface of the water distorts the reflections in wavy and loopy patterns.

And this one, well this one is just for fun!

Although it might have been a bit to abstract for Sir Isaac's tastes.

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