I received an e-mail stating this. But I haven’t seen this on any news sites, so I have my doubts. Perhaps the e-mail was exaggerating?
The close approach of Mars to Earth was in 2003. But many people skipped the little part about Mars looking as large as the moon at 75x magnification. If Mars looked that big to the naked eye we’d be in for a world of hurt.
To look as big as a full moon Mars needs to get closer than 1 million km from Earth. Not gonna happen.
On the other hand, Mars will very likely look bigger than a new moon. So there.
Thanks, my BS meter seems to be working.
My girlfriend got that stupid e-mail from two of her siblings on the same day; she wouldn’t let me reply to them and explain why it’s not true.
Did everybody get amnesia? Two years ago, a fairly big deal was made about how close we were going to be to Mars, and how bright it would be. (And it was!) My girlfriend’s siblings are nice people, but Jeez.
I can’t believe those E-Mails are being circulated annually now.
Yes, I got plenty in 2003. And in 2004 I received a few. I replied to these stating that NO - it only applies to 2003.
And I did receive one this year and I gave the usual reply.
Gee, I’ll be disappointed if no one sends me one for 2006.
Err … i hope you ment that it will be close to Earth applies. Not that it will
look as big as the Moon.
All versions of the email I’ve seen, it qualifies it by saying, under 75x magnification, Mars will look as big as the full moon. That applies to late August 2003
Yes, I guess I should have stated that more clearly.
- I tell people it only applied to 2003 and
- It won’t appear as big as the Moon unless you are using magnification.
That was my reply in 2003, 2004 & 2005 and I’ll be telling the same story to the people who send me that E-Mail in 2006. (You just know someone will.) 
My wife has gotten this Email twice. The once she got specifically said that Mars would look as big as the full moon to the naked eye.
She sent the first one to me and I sent back explaining what was going on. She sent that on to the person who sent it to her and got back “I don’t care if it isn’t really true, I’m gonna beleive it because it’s cool.”
This attitude goes a long way to explaining why our mission here at the SDMB seems to be failing.
It also explains some political realities, come to think of it.
I had a 70-year old, otherwise intelligent but new to the Internet, tell me about the Mars thing last night. He assured me that it would be as large as the full moon, but wasn’t sure of the date.
And when the date this is supposed to happen comes around, you know where they’ll be for this incredibly cool event - in the living room watching FOX network’s latest new reality show, “Who Wants To Survive My Average Wife-Swapping Geek Wedding?”
Won’t even peek out the window to see the amazing giant Mars; you can stake money on it.
“Have you heard, it’s in the stars: next July, we collide with Mars!”
If Mars were visibly as large as the moon, that infamous song line would be true.
If Mars truly were 1,000,000 km away, how bad would it be for us?
It’d be two and a half times farther than the moon, but it has what about 8 times the mass? So, it would cause tides that would be smaller than the lunar tides, but about the same size as the solar tides.
Well, yeah, but that would be just the opening the Martians are looking for to invade.
Streets full of people, all alone
Roads full of houses, never home
A church full of singing, out of tune
Everyone’s gone to the moon
The above is correct…I’ve seen this mis-statement quoted again and again since the last “closest-ever-in-the-history-of-man-never-to-be-seen-again” encounter with Mars! 
- Jinx
More to the point; for Mars to appear the same size as the moon, to the naked eye, something would have to have wrenched it out of its normal orbit and that something would almost certainly be A Really Bad Thing for the solar system in general.
You’re making this harder than you need to. Tidal forces are proportional to density times angular size cubed. We’re assuming that the angular sizes are the same, and the densities of Mars and the Moon are comparable (certainly, both are denser than the Sun), so if Mars appeared as big as the Moon, then it would produce tides comparable to those of the Moon.
What’s funny about this e-mail is that I didn’t hear anything about this in 2004, and I didn’t encounter any of the exaggerated claims in 2003, but I’ve heard it several times from different sources this year (including the ridiculous “as large as the Moon to the naked eye” claim). What’s giving this thing legs?