Between Science and Theology: How science learns about unobservable entities

Cropped from Hairy Dark Matter By NASA/JPL-Caltech [Public domain], via Wikimedia Commons
In 1800, someone took the temperature of a rainbow. This story isn’t as strange as it sounds because that ‘someone’ was not the sort of person to look for a pot of gold, but a scientist called William Herschel.

Lemuel Francis Abbott [Public domain], via Wikimedia Commons
Herschel was a German musician and astronomer who became famous for discovering the planet Uranus. He built the best telescopes of his day, was funded by King George III, became a fellow of the Royal Society, first president of the Royal Astronomical Society, and was eventually knighted for his work. So why was such a sensible person taking a rainbow’s temperature? Continue reading