April 1: Carl Charlier

Carl Vilhelm Ludwig Charlier

April 1, 1862 – November 5, 1934

Carl Charlier was a Swedish astronomer. He received his Ph.D. from Uppsala University in 1887, later worked there and at the Stockholm Observatory and was Professor of Astronomy and Director of the Observatory at Lund University from 1897.

After working in celestial mechanics, the calibration of photographic photometry, and the theory of lenses, he turned to statistics. He made contributions to pure statistics, especially the theory of errors, and made extensive statistical studies of the distribution and motions of stars in the solar neighborhood. 

Related to his work on galactic structure, he also developed a cosmological theory based on the work of Johann Heinrich Lambert. In the resulting Lambert-Charlier Hierarchical Cosmology, increasingly large areas of space contain decreasing densities of matter, the principle being introduced to avoid the observational inconsistency that would otherwise emerge from Olbers Paradox.

In his later years he became interested in the history of astronomy and translated Newton’s Principia into Swedish.

He received the James Craig Watson Medal in 1924 and the Bruce Medal in 1933. The Lunar crater Charlier, asteroid 8677 Charlier and a crater on Mars are named in his honor.