Mars attacks again, again

Bad Astronomy
The entire universe in blog form
Aug. 8 2006 10:26 PM

Mars attacks again, again

That's not a typo.

That &)#@)(&%$) email is being sent around again, saying that Mars will look as big as the moon on August 27. That email was sent out in 2003 and again, reproduced almost exactly, in 2005.

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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And here we are, again, so I have to debunk it, again. I wrote up yet another web page about this email. This makes the third time I've had to do it, too. Sigh.

If you have any lingering doubts, this image may clear them up.

It's a telescopic view of a very rare event: the Moon passing directly in front of (what astronomers call "occulting") Mars. Look at the size difference! Physically, Mars is about twice the size of the Moon. But even at best it's more than 140 times farther away, so it appears -- again, at best -- about 1/70th as big as the Moon.

Oh -- on August 27th, 2006, Mars will be about as far away as it can be, since it's on the other side of the Sun from us right now. So it'll be invisible for all practical purposes, lost in the glare.

So there you go. If you're looking for a giant Mars looming above you in the sky, you'll have to wait until you can buy a ticket and go there.

Update (Aug. 22, 2006): I neglected to add a credit to the image above. It's Ron Dantowitz, Clay Center Observatory at Dexter and Southfield Schools, and clicking it will take you to a site with fantastic images in the gallery!

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