Wednesday, July 27, 2005

Urban astronomical myths

This time it's e-mail messages saying: "By August 27, Mars will look at large as the full moon to the naked eye."

Mind you, as usual there is a germ of truth to the rumor. On July 17 Mars was at perihelion, its closest to the Sun in space. In early November Mars is at opposition, in a line with Earth on the same side of the Sun, and as close to Earth as it gets (at least for the time being). Even then its disk will only be about 1/100th the diameter of the full moon and about 1/10,000th as bright. Mars will be high in the south at midnight, in the constellation Aries, and perfectly situated for viewing all night long.

In 2003 Mars came closer to Earth than at any time between 57,617 B.C. and 2287 A.D. We had another round of e-mails then.

On November 14, the almost full Moon and fat Mars will be close together in the sky. You can check out the rumor for yourself.

A little puzzle for you: Mars is at opposition on November 7, but is actually closest to Earth on October 30.