SO CLOSE YOU CAN SEE JOHN CARTER

August 2003 Close Approach (Jeffrey Bennett, physics.sfasu.edu)

A number of you have already asked about the upcoming "close encounter" with Mars, so I've checked into the story behind it. Here's the basic facts in Q&A format:

[Q:] Is it true that this will be the closest pass of Mars in 60,000 years?

[A:] Yes. Based on calculations of planetary orbits, it appears that on August 27 of this year, Mars will be closer to Earth than it has been at any time since 57,538 BC, which is just shy of 60,000 years ago.

[Q:] So is this really "the best opportunity to observe Mars in 60,000 years"?

[A:] Technically yes, but in reality Mars passes almost as close to Earth about every 15-17 years, and the difference between this pass and other close passes is too little to really notice.

[Q:] Will the close pass affect Earth?

[A:] Remember that "close" is a relative term. Mars will pass 55.758 million kilometers (34.6 million miles) from Earth. That's still roughly 150 times farther away than the Moon. Other than being bright in the sky, this close pass of Mars will not have any effect on Earth whatsoever. (For example, the tidal effect of Mars at this distance is roughly a million times weaker than the tidal effect we feel from the Moon.)

[Q:] Is it worth observing?

[A:] Sure! Even if other close passes are just about as good, they come almost two decades apart. So this will be one of a handful of "best" opportunities to view Mars in your lifetime.

[Q:] How do I go about viewing Mars?

[A:] If you go out on a clear night right now, you can't miss it - Mars is the bright red object in your sky. Viewing will remain good through September, peaking on the August 27 close pass date. If you want to observe Mars through a small telescope, check out this article from Sky and Telescope: S&T Article

It's interesting how fiction has given Mars a romance that few celestial objects share. Posted by Orrin Judd at August 10, 2003 6:45 AM