June 29 – Birth of George Ellery Hale (1868)

Born today in Chicago, 1868, son of a genius (an elevator manufacturer in 19th century Chicago – what other word could describe him?), George Ellery Hale was a busy man. As well as being professor at Beloit College and the University of Chicago, he was author of several books, many papers, editor of the Astrophysical Journal and played a large role in founding Caltech.

In 1908 Hale showed that sunspots are magnetic. He followed this up by proving their East-West alignment, and their tendency to switch polarity between sunspot cycles. This work alone, as his obituary in the journal of the Royal Astronomical Society of Canada points out, would have been enough to gain him a place among the greats of astronomy, but it was his drive to organise others into building ever better and bigger telescopes that has assured his legacy (we will here skip ever so quickly over the alleged small elf, who apparently told Hale how best to persuade Rockefeller to cough up the six million dollars needed for his largest telescope; after all, who am I to tell a visionary genius what he can or can’t see?).

George Ellery Hale
George Ellery Hale

Hale’s quest for large telescopes led to some of the biggest ever. They included: the 60″ telescope at the Mount Wilson Observatory, near Pasedena, used to measure the size of the Milky Way and find our position in it; the 100″, also at Mount Wilson and completed in 1917, used by Edwin Hubble to study galactic velocities; and the monster 200″ at Palomar Mountain, southeast of Pasadena, with its 40 ton pyrex mirror. Unfortunately, due to the unbelievable complexity of building such a device, Hale had died long before Hubble made the first exposure in 1948.

1851  –  Discovery of asteroid 15 Eunomia, the largest S-type asteroid, by Annibale de Gasparis.  Eunomia is elongated in shape, and over 300km across at the widest point. In Greek mythology Eunomia was the goddess of lawfulness and good governance. Her nemesis was Dysnomia.

1888  –  Birth of Alexander Friedmann, Russian physicist, who came up with the Friedmann equations, to explain the expansion of the universe.