For nearly as long as Los Angeles has been a city, the sky above it has changed colors, for short and long spells, at times portending doom. It happened again this week.

LOS ANGELES — While Los Angeles is home to the biggest stars in the world, a monthly get-together is proving that the city’s rich and famous have nothing on the universe.

F or nearly as long as Los Angeles has been a city, the sky above it has changed colors, for short and long spells, at times ...