UPDATE:  SOLVED!

Last week it took about 4 hours to solve the riddle, so this week it’s much simpler.  Really.  It’s very simple.  I’ll be surprised if it’s unsolved for longer than 15 minutes.  Really.

Are you ready?  GO!

Although thought of as a single object, it is not.

This was well-known in antiquity, and was once thought to effect terrestrial events.

Can be seen from almost every inhabited region on Earth.

It’s been described as being three different colors.

Has been mentioned in literature since the 7th century BC, and is well represented in popular fiction.

Has been seen as a sign of both good and evil fortune.

This is sometimes visible to the naked eye in the daylight.

Sometimes it shows up twice in one night.

What is it?  I’m hanging out in the comment section (as usual), so give it a guess!