The video: Stargazers have a once-in-a-decade chance this month to catch a "beautiful gathering" of the planets Mars, Jupiter, Venus, and Mercury. (See an animation below). Other than the moon, the four tightly crowded planets will be the brightest things in the sky. People in southern states will have the best pre-dawn view of the planetary quartet, while those further north may need binoculars, and Wednesday provides one of the best opportunities to view what NASA calls the "Great Morning Planet Show." To catch a glimpse, stake out a spot with an unobstructed view of the eastern horizon 30 to 45 minutes before sunrise.

The reaction: "It's definitely worth a look," says Julie Hoogland in The Grand Rapids Press, because "the planets don't align like this every day." Indeed, "this is the tightest grouping of bright planets that has occurred yet in the 21st century," says Tony Flanders in Sky & Telescope. And the day-to-day movement of the foursome will make for a "fascinating dance with each other," says Joe Rao at Space.com. "We could even refer to this as a 'celestial summit meeting.'" Watch a NASA video about the dancing planets: