An observatory perched above smog-choked Los Angeles sounds like a bad idea, but the same inversion layer that traps the city's haze gives Mount Wilson unusually steady air. This episode follows George Ellery Hale from his 1904 lease of the 5,710 foot peak, with a clause guaranteeing public access, through the Snow Solar Telescope, the 60-foot and 150-foot solar towers built to escape ground heat shimmer, and his 1908 discovery of magnetic fields in sunspots via Zeeman splitting. The hosts recount the 60-inch mirror gifted by Hale's father, its mount barely surviving the 1906 San Francisco earthquake, and the 100-inch Hooker telescope floated on vats of liquid mercury and housed in a dome pre-assembled in a Chicago lot.

The conversation then turns to the discoveries: Edwin Hubble's 1923 Cepheid variable in Andromeda proving it was a separat ...