What is the zodiacal light — or “false dawn”?
Monday, September 21, 1998 DB: This is Earth and Sky for Monday, September 21. Now that the moon is back in the evening sky, make a note to yourself to look in the sky before dawn. JB: In the next couple of weeks, you’ll have a chance to see an autumn phenomenon — a pyramid of light in the predawn sky — if you find a place where the sky is dark. This is the zodiacal light, best seen from this hemisphere in the east before dawn at this time of year. The zodiacal light was called the “false dawn” in the Rubiyat by Omar Khayyam. Look for it about an hour before the real dawn begins, before any trace of twilight appears in the eastern sky. DB: The zodiacal light is really sunlight bouncing off dust grains in our solar system. These grains lie mostly in the plane of the solar system — that’s why you see the light in a line leading up from the horizon instead of spread out all over the sky. And it’s why you can see the light most easily from this hemisphere at this time of year. Right now
