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Re: False dawn

Posted by Smokey Stover on August 10, 2007

In Reply to: False dawn posted by OJ on August 10, 2007

: What is a "false dawn"? and where does it come from?

Another name for it is "sodiacal light." An excellent source for the information you want is at:

http://www.space.com/spacewatch/zodiacal_light_021101.html

I'll quote a bit of the description there:

"At certain times of year in the right locations, a faint cone of light appears in the predawn sky for lucky viewers in dark locations. This eerie glow is the Zodiacal Light.

"It is best seen before daybreak, generally two to three hours before sunrise in the eastern sky. But its also visible in the west at certain times of year.

"Over the centuries countless individuals have been fooled into thinking the Zodiacal Light was the first vestige of morning twilight. In fact, the Persian astronomer, mathematician and poet Omar Khayyam, who lived around the turn of the 12th Century, made reference to it as a "false dawn" in his one long poem, The Rubaiyat....

"It was once thought to be solely an atmospheric phenomenon: perhaps reflected sunlight shining on the very high atmosphere of Earth.

"We now know, however, that while the phenomenon indeed involves reflected sunlight, it is being reflected not off our atmosphere, but rather off a nonuniform distribution of space debris left over from the formation of the planets some 4.5 billion years ago."

By "the East" is generally understood, I believe, the Middle East, where it is more commonly seen and there are more travelers' reports of it.
SS