Mars? Not so close!

Planet Mars as imaged by NASA.Every year some of us receive an email that says something like: "The Red Planet is about to be spectacular!" Or "On August 27 Mars will be as big and bright as the full Moon." There's even a PowerPoint presentation making the rounds this year!

This particular "urban legend" has been circulating since 2003. It wasn't true then. It's not true now. It will never be true... well, not in anything short of geological or astronomical time spans of billions of years!*

Nor would we want that bit about "...big and bright as the full Moon..." to be true anyway. If the two rocky planets were that close, oceanic tides would be twice as high as they are now and there might be other unhappy consequences. Fortunately on January 27, 2010, at its next "close" approach,  Earth and Mars will be a good 62 million miles apart. Mars will never look like anything more impressive than a brightish red star to the unaided eyes of the Earthbound.

Mars is notoriously difficult to observe through small telescopes even with high magnification. Earth's best images came from the orbiting Hubble Space Telescope. We had to send spacecraft all the way to Mars to improve over Hubble's view and are only beginning to unveil its surprises.

You can, if you get up early, see Mars in the pre-dawn sky this month. Look low in the east for  two planets: brilliant, silvery Venus and dim, red Mars will appear in the sky near each other through July 2009.

And no, Venus and Mars aren't actually close to each other; usually they're even farther apart in space than the Earth is from Mars!


* There's recent discussion over a theory that, in the solar system's old age, the planets' orbits may have perturbed enough to result in collisions. On that time scale, however, the Sun's own decline will have caused it to swell enough to destroy the inner planets. So don't worry about it.

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