Skeptic History: Astronomy vs Astrology PDF Print E-mail
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Written by Tim Farley   

When the planet Uranus was discovered on March 13, 1781, it caused a conundrum for classical astrologers. Their rules revolved around a system of exactly seven heavenly bodies (5 planets, the moon and the sun). Seven is a magical number, of course. Adding an eighth body ruined the magic.

But Uranus also posed a problem for real scientists too, who noticed anomalies in its orbit. French astronomer Urbain Le Verrier, who was born March 11, 1811, calculated that they could be explained by motion of an unseen planet beyond Uranus. Based on his calculations, Neptune was in located via observations in 1846.

Le Verrier went on to examine anomalies in Mercury’s orbit, and predicted the existence of another inner planet he called Vulcan. Astronomers spent many years trying to observe the predicted planet with no success.

Years later came Albert Einstein, who was born March 14, 1879, and his theory of general relativity. It fully explained the anomalies in Mercury’s orbit without need of an unseen inner planet.  

LeVerrier, who had been so right about Neptune, was absolutely wrong about Vulcan.  But did this sully his reputation?  Not at all.  His prediction of the location of Neptune is still regarded as a triumph of the predictive abilities of science.

And besides, if you’re going to be proven wrong, why not by Einstein?  In addition to being the most famous physicist ever, in 1999 Skeptical Inquirer named him one of the ten most outstanding skeptics of the twentieth century.  (Also listed, of course, was James Randi).

But what about the problem Uranus and Neptune posed for astrologers?  Well, astrology did suffer a decline in popularity during early nineteenth century as a result.

But soon western astrologers found a way to incorporate both Uranus and Neptune into their bogus predictions.  Astrology is unfortunately more popular than ever today.  How that happened is a story for another day.

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(This essay originally appeared in a slightly different form on Skepticality episode #123)


Tim Farley is a JREF Research Fellow in electronic media.