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Attracted by the light

A solstitial exploration of brightness
RELATED TOPICS: SUN
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Last month, our topic was darkness. Let’s make it a two-parter and focus now on light. This makes sense, for we’re now in the realm of greatest sun and longest twilight. If you live north of latitude 50°, for instance anywhere in England, full darkness never happens in June.

The brightness story begins with photons, the universe’s most abundant objects. Contrary to popular belief, photons have neither luminosity nor color. They are magnetic and electrical pulses. You can’t see magnetism and you can’t see electricity. So when no one’s watching, garden roses are not red, nor is grass intrinsically green. They’re not even black, but blank. Photons do deliver the electromagnetic force, which triggers some of our cells to respond electrically, producing the subjective perception of light. As physicist Roy Bishop says in the Observer’s Handbook from the Royal Astronomical Society of Canada, a rainbow occurs strictly inside your skull.

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