Since its founding in 1891, many people have passed through the doors of the Vatican Observatory. A quick perusal of our guestbook reveals several Names, including Popes, nobel laureates, astronauts, actors, and saints.
Today's guestbook entry is from June 5, 1909, when George E. Hale made a visit.
Next to his name, George Ellery Hale (1868-1938) wrote "Mt. Wilson Solar Observatory, California."
The year prior to his visit, he used the Zeeman effect--(see the previous post on H. A. Lorentz)--to discover magnetic fields in sunspots.
He also found that, between sunspot cycles, the magnetic polarity of fields through sunspots in northern vs southern hemisphere switches orientation - what is today known as Hale's Law (or the Hale-Nicholson Law).
In 1913, Hale advised Albert Einstein of the possibility of observing the effects of general relativity on starlight passing near the Sun, which he suggested might be possible during a total solar eclipse. This led to the eclipse observing expeditions of Arthur Eddington and others in 1919 that confirmed this aspect of relativity theory.
Hale is perhaps most known for his work organizing the construction of large telescopes. He is responsible for the 40-inch refractor at Yerkes Observatory, the 60-inch Hale telescope at Mount Wilson Observatory, the 100-inch Hooker telescope at Mount Wilson, and the 200-inch Hale telescope at Mt. Palomar.
The reputation of the California Institute of Technology (aka Caltech) as a leading research institution also started largely due to the work of George Hale.
There are craters on the Moon and Mars that bear his name as well as the asteroid (1024) Hale, and the terrestrial mountain Mount Hale in the Sierra Nevada range.