March 19: Franz von Gruithuisen

Baron Franz von Paula Gruithuisen

March 19, 1774 – 1852

Franz von Gruithuisen was a Bavarian physician and astronomer. He taught medical students before becoming a professor of astronomy at the University of Munich in 1826.

During his period of medical studies and instruction, he was noted for his contributions to urology and lithotrity. He developed ideas on safer methods to remove bladder stones transurethrally, and his instruments served as models for subsequent devices.

Like others before and since his time, Gruithuisen believed that the Earth's moon was inhabitable. He made multiple observations of the lunar surface that supported his beliefs, including his announcement of the discovery of a city in the rough terrain to the north of Schröter crater he named the Wallwerk. This region contains a series of somewhat linear ridges that have a fishbone-like pattern, and, with the small refracting telescope he was using, could be perceived as resembling buildings complete with streets. He published his observations in 1824, but they were greeted with much skepticism by other astronomers of the time. His claims were readily refuted using more powerful instruments.

He is also noted for the discovery of bright caps on the cusps of the crescent Venus, for being the first to suggest that craters on the Moon were caused by meteorite impacts and for his prolific rate of publication. He proposed that jungles on Venus grew more rapidly than in Brazil due to the proximity of the planet to the Sun, and that as a consequence the inhabitants celebrated fire festivals— the cause of the bright caps on Venus.

The crater Gruithuisen on the Moon is named in his honor.