It's August soon, so it's the time of year for the Mars email to start going around again...
http://www.snopes.com/science/mars.asp

If you read the article you will understand why this one is a double whammy. It is based on a "true" incident in 2003 when the planet Mars did make a very favorable close approach to earth in August of that year, but it was no where near as large as a full moon. The same email went around in 2004 and 2005, and was such a prevalent "frequently asked question" on astronomy web sites, that Sky & Telescope, and Phil Plait's Bad Astronomy, both had to run pages debunking the email.

When Mars has an opposition in August or September, when it is close to the perihelion point in its own orbit, and the earth happens to pass it in its orbit, then the opposition is particularly favorable, as it was in 2003, and several other times during my lifetime so far. This year Mars reaches opposition in December, not August, but already it is getting close enough to allow astronomers with decent sized telescopes to take images of a large dust storm like the one above.

But this is an opportunity to discuss, yet again, what makes this particular email so annoying to me as an amateur astronomer, science enthusiast, and internet maven/guru.

First of all, the "bad astronomy" angle. In 2003 when Mars did actually have a favorable opposition, the person who wrote the original "enthusiastic" email about it was trying to get people to take a once in a lifetime opportunity to see the red planet at its finest- that much is TRUE! But they got a little confused about the "full moon" part. When Mars, or any superior planet, is at opposition to the sun, it is also at the point in the sky opposite the sun, so it is similar to a full moon, and if there is a full moon, the planet will appear near it. That's my guess as to why the author of the original email four years ago suggested that the planet Mars would be as large as, or spectacular as, the full moon in the sky. But of course, Mars never gets that large to the unaided eye, and even in a telescope, it is a challenge to see much detail on its surface, especially right now because of the dust storm that is affecting the Mars rovers that are still crawling around on the surface(!).

Next thing that "gets me" is the general ignorance of basic science that allows this misinformation to continue to get routed around without anyone realizing immediately that it must be bogus. What I am saying is, if most people read the news about science, or understood it, they would know immediately that this is ridiculous. If people had been reading in the news about how the dust storm on Mars is affecting the rovers, they would probably know enough about the real science involved that they would be able to spot the bogus email immediately. For example:

http://www.redorbit.com/news/space/1014517/spirit_rover_sees_dustier_martian_sky/index.html

... here is a recent story about Mars, that can be found on any number of science and astronomy related websites.

The third thing that "bugs" me about this is because it illustrates the "information pollution" that the world wide web has made prevalent. Just because you get something by email, or just because you look something up online, doesn't mean it is real. IN fact, the ability to send email at the click of a button, and send it around the world on multiple networks, has just made the problem of "bad" information worse. Some sites like Wikipedia rely on members to check the validity of the information that has been written, and it already has an impressive amount of great information. But in general, most things you look up on a Google search must be presumed to be BOGUS until proven otherwise. I could take this discussion one step further and mention that most online interaction in social networking sites is done by people who are misrepresenting some or all of the information about themselves, but this is supposed to be an astronomy blog, not a missive on society in general. Besides you have heard my rant on that topic before. To quote my friend Pete, we are all DOOMED!

Phil Plait's Bad Astronomy article...
http://www.badastronomy.com/bablog/2007/07/27/mars-wont-be-as-big-as-the-moon-get-over-it/

Hey, you know what- look at the picture of the eclipsed moon in my previous blog entry(!). That is similar to how it may appear on August 28 during the upcoming lunar eclipse. Suppose someone who got the Mars email goes outside at o-dark-thirty the morning after the 27th and sees the reddish eclipsed moon hanging low in the pre-dawn sky(!?!). They might actually think they are looking at the planet Mars!