Mars (dis)information

Another August is here, and that means it’s time for the Mars/Moon emails to start going around again.

If you haven’t received one, they go something like this:

Planet Mars will be the brightest in the night sky starting August!

It will look as large as the full moon to the naked eye. This will cultivate on Aug. 27 when Mars comes within 34.65M miles of earth. Be sure to watch the sky on Aug. 2712:30 am. It will look like the earth has 2 moons. The next time Mars may come this close is in 2287.

Sorry to disappoint, but the information is inaccurate. Like so much else on the Internet, it (once) had a kernel of truth to it, but has since gone awry.

In 2003, Mars had an exceptionally close opposition to Earth. (Opposition is when the Sun, Earth, and another far-away object lie in a straight line to one another. The object is therefore opposite the Sun in our sky.) Mars lies in opposition every 20 months or so, but in 2003, it occurred when Mars was near its closest point to the Sun, which put it unusually close to the Earth.

“Unusually close,” in this case, meant 34,649,589 miles. The Red Planet did appear six times larger and much brighter in our sky than usual, but it was nowhere near “as big as the full Moon.” The original email’s author did, in fact, use that phrase, but went on to mention that one would have to use a telescope and an eyepiece giving 75x power to see it. Naturally, those boring, technical details were dropped somewhere during the countless subsequent iterations of email forwards, changing the meaning of his simile.

Since then, like clockwork, each August the emails make their rounds through the Internet again. Mars isn’t even near opposition this August. That occurred last December.

You may be disappointed to find out the truth, but there’s a silver lining: if you stepped out on your back patio and saw Mars was as big as the full Moon, chances are that it would probably be the last thing you ever saw. Earth and Mars would not make good neighbors.

The first thing you would notice, aside from the pretty view, would be a wobble in the Earth’s rotation, as the two planets’ gravitational fields wreaked havoc with one another. This would be quickly followed by the Earth’s crust fracturing apart, as parts of it try to keep spinning and others don’t. Geophysical activity — earthquakes, volcanoes, freaking-mountain-high-fire-fountains-of-molten-death — would dispatch most of the Earth’s inhabitants rather quickly, and oceanic flooding would take care of the rest (until the oceans boiled away, that is). Any survivors would enjoy the pleasure of having the air pulled from their lungs as they rode large chunks of Earth’s crust into the void as the planet broke apart. Where the view would be spectacular, I imagine.

Sorry, I get carried away sometimes. But seriously, the email is fake.

“Whaaa?!? You’re doing astronomy posts again?” Looks that way. Stay tuned for more.

2 Responses to “Mars (dis)information”

  • So it’s not August 27, but September 27 (really the 26th) and through my bedroom window 3 am (the baby was awake!) was the most beautiful star I have ever seen! The colors “twinkling” off of it! I hope you got to see it! Of course, these clear Wisconsin skies we do see things clearer than most people get to.
    Would that be Mars? I know I am completely astronomically(?) illiterate!

  • 3am… lots of twinkling… I’m thinking Capella. Were you looking east- or northeast-ish?

    I remember when I was working the scope at the observatory, we’d get the most phone calls about Cappella (and Venus). Cappella is a pretty bright star, and it rises at this low, shallow angle - staying close to the horizon for a long while. Lower in the sky means more twinkling, and for a bright star like Cappella, it seems to quiver in the sky like angry candy.

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