BEWARE THE MARS HOAX: It's August, which means it's time for the annual Mars Hoax. An email is going around claiming that Mars will approach Earth on August 27th; the encounter will be so close, the email states, that Mars will rival the full Moon in size and brightness. (Imagine the tides!) Don't believe it. The Mars Hoax email first appeared in 2003. On August 27th of that year, Mars really did come historically close to Earth. But the email's claim that Mars would rival the Moon was grossly exaggerated. Every August since 2003, the email has staged a revival.I, personally, have never gotten that mail. I would laugh hysterically at it, and if any of my friends sent it to me, I would pity the education they received as children, because their school system would have failed them.
I wanted to see this letter, so I went to snopes, and 23 popups later, saw the actual text of an example letter. Here's the humorous facts as I see them: first Mars has a diameter of roughly 6800km, and the moon is almost 3500km. This means Mars is almost twice as big. I would imagine that Mars would have to be further away than the moon. The moon varies from 356,000km to 408,000km away. I would imagine that would have us believe Mars was about 700km away from us "at its closest."
Mars orbits at an average of 227 million km away from the sun (like all planets, the orbit is a tad bit elliptical). Earth is closer to the sun, keeping Toronto and Vancouver away from pesky glaciers, at about 149 million km. That's a little over half the distance closer to the sun. Mars has an elliptical orbit, but not THAT elliptical.
The chaos of a flyby that close of a body the size of Mars would be horrific. Space Weather mentioned tides, but that would be the least of our worries. The gravity of a passing body that size that close would alter the Earth's orbit significantly. Assuming it was still in the same orbital plane, it would most likely nudge us into a new path that would send us towards the sun. Maybe not into the sun, but that would be moot. As we hurtled in our new path, if we got close enough to the sun, solar winds would overcome our magnetosphere, and Toronto and Vancouver wouldn't have to worry about those glaciers... or anything... ever again. UV light would cook us, and our atmosphere would strip away like panties at a drunken lesbian sorority party. Oh, and a little known fact: getting closer to the sun makes you hotter! Then, as we headed faster and faster towards the sun, those few humans who holed up in caves with oxygen tanks would find the surface heating up like the mantle below them. Maybe they'd survive. And what a world to come back to! Because when we spin away from the sun, and things cool down... and keep cooling... and keep... hey, maybe we should have turned back at that asteroid belt! No? Still going?
Our orbit would become very erratic like Pluto, and whatever scientists left would be forced to possible demote our frozen ball of rock from "planet" to "no fun at all." Meanwhile, Mars didn't just go away. Whatever forces it encountered to suddenly make a journey of 80 million km off course to our little neighborhood would have it keep on going. Maybe it would crash into the sun. Maybe it wouldn't. Its flyby with us would have altered its path; the Earth's diameter is nearly twice the diameter (size queen) and ten times the mass. Not to mention the moon, who may have seen where this was going and opted not to take the solar tour with us. Or maybe it ditched us near Venus. That planet always needed a moon.
And maybe we'll all meet again somewhere in a million years in a huge welcoming party that looks a lot like rubble going in all directions. I bet Venus will regret keeping the new moon.
A source I used: http://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html