Sometimes the Internet is like that.
Background: a year and a half ago, in August 2003, there was an unusually favorable Mars opposition. Mars has a year roughly double ours, so Mars "oppositions" happen about every two years (plus a few months). An opposition is when we and Mars are both on the same side of the sun (so the sun is opposite Mars in our sky, and Mars is at its highest at midnight). We're much closer to Mars at opposition than at other times, and that makes a big difference on a planet as small as Mars, so for people who like to observe Mars with a telescope, oppositions are the best time to do it.
The August 2003 opposition was the closest opposition in thousands of years, because Mars was near its perihelion (the point where it's closest to earth) at the time of the opposition. Much was made of this in the press (the press loves events where they can say "best in 10,000 years") to the point where lots of people who aren't normally interested in astronomy decided they wanted to see Mars and came to star parties to look through telescopes.
That's always nice, and we tried to show them Mars, though Mars is very small, even during an opposition. The 2003 opposition wasn't actually all that favorable for those of us in northern hemisphere. because Mars was near the southernmost part of its orbit. That means it was very low in the sky, which is never good for seeing detail through a telescope. Down near the horizon you're looking through a lot more of Earth's atmosphere, and you're down near all the heat waves coming off houses and streets and even rocks. That disturbs the view quite a bit, like trying to see detail on a penny at the bottom of a swimming pool.
This year's opposition, around Halloween, will not be as close as the 2003 opposition, but it's still fairly close as oppositions go. Plus, this year, Mars will be much farther north. So we're expecting a good opposition -- weather permitting, both on Earth, which is sometimes cloudy in November, and on Mars, where you never know when a freak dust storm might appear.
Which brings me back to the game of Telephone.
A few weeks ago I got the first of them. An email from someone quoting a message someone had forwarded, asking whether it was true. The message began:
The Red Planet is about to be spectacular! This month and next, Earth is catching up with Mars in an encounter that will culminate in the closest approach between the two planets in recorded history.and it ended:
Share this with your children and grandchildren. NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN(sic on the caps and the lack of a period at the end).
I sent a reply saying the email was two years out of date, and giving information on this year's Mars opposition and the fact that it may actually be better for observing Mars than 2003 was. But the next day I got a similar inquiry from someone else. So I updated my Mars FAQ to mention the misleading internet message, and the inquiries slowed down.
But today, I got a new variant.
Subject: IS MARS GOING TO BE AS BIG AS THE MOON IN AUGUST?
As big as the moon! That would be a very close opposition!
(Dave, always succinct, said I should reply and say simply, "Bigger." Mars is, of course, always bigger than the moon, even if its apparent size as viewed from earth is small.)
It looks like the story is growing in the telling, in a way it somehow didn't two years ago.
I can't wait to see what the story will have become by August. Mars is going to hit us?
[ 11:48 Jun 17, 2005 More science/astro | permalink to this entry | comments ]