The perennial Mars hoax e-mail !

Don't panic. Mars is not about to pull up alongside earth

By Finlo Rohrer BBC News Magazine

Every August e-mails circulate which suggest we are about to have a close encounter with Mars. The e-mails are a hoax, but they say something about our fascination with the Red Planet.

The e-mail seems to promise something truly remarkable.

It often starts: "The Red Planet is about to be spectacular."

It ends with the screaming caps: "NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN."

The message tells of Mars being close to the earth on 27 August, close enough to be as big as the moon with the naked eye.

Sadly, in three weeks' time, on 27 August, Mars will be a long way away. But between then and now, astronomers will be bombarded with questions by curious punters about this close encounter.

"The e-mails and rumours go out every year but it isn't true. It's something we get asked in the planetarium a lot," says Dr Claire Bretherton, astronomy learning officer at the Royal Observatory Greenwich. "I get e-mails from my friends to me to check whether it's true."

Keith Cooper, editor of Astronomy Now magazine, is also well used to getting a sprinkling of Mars hoax e-mails every year.

"It seems to do the rounds all the time. Often there are people asking about it. It's variations on a theme, it isn't the same e-mail each year.

"I'm not sure how it started or who keeps propagating it. But it does seem to be prevalent."

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The strange thing about the hoax e-mail is that most of it was true… in 2003.

Then, on 27 August, Mars came within 35 million miles (56 million km) of Earth. That compares very favourably with the next close encounter. At the end of January 2010 it will be 66 million miles (99 million km) away.

"It happens because the earth goes around the Sun in 365 days and Mars goes around in 685 days," says Prof Colin Pillinger, mastermind of the Beagle 2 component of the Mars Express mission. "The Earth's orbit is only very slightly elliptical. Mars is a very elliptical orbit."

Every 26 months there is a close encounter. And every 17 or so years there is a really close encounter.

But the e-mail does cause most recipients to get one thing completely wrong. Mars will not appear as big as a full moon to the naked eye.

If this scenario occurs, you are probably trapped in the plot of a bad Jerry Bruckheimer movie.

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"It says it will be as big and as bright as the full moon, which is impossible," says Dr Bretherton. Tides would be dramatically affected. "It would basically have the same effect as the Moon does. It could cause chaos."

The original version of the e-mail makes things reasonably clear. "At a modest 75-power magnification Mars will look as large as the full moon to the naked eye." So, with a fairly large amount of magnification Mars looked as big as the moon did with none.

Sadly, as has been noticed on urban legend sites like Snopes, that have dissected the e-mail, many readers have read the sentence as: "Mars will look as large as the full moon to the naked eye."

So subsequent e-mails have not only omitted the date, but also have come with the misleading catchline: "Two Moons".

One would think anyone receiving it would realise something was amiss. "Most people believe the bit about it being closest, a lot of people think twice when they hear the bit about it being as big as the full moon," says Dr Bretherton.

But even Nasa has a page explaining the mythology behind the e-mail.

It notes that far from being close on 27 August, Mars will be so far away, 250 million kilometres, as to be "completely absent" from the evening sky.

So if the e-mail is so obviously not true, why do people keep circulating it?

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It might just be because they are so thrilled by the idea of a true astronomical spectacle, says Dr Bretherton.

"People keep seeing articles on the internet and start circulating them. The idea that there is going to be something amazing in the sky is something that gets them enthusiastic."

And Mars also has a cultural status that makes anything to do with it seem particularly alluring. It's the Red Planet, sharing a name with the god of war, defining character traits like anger and strength in astrology.

It also has a more recent connotation. Aliens.

"It's the place mostly likely to have life," says Prof Pillinger. "It's the place that science fiction nasties come from."

Wells' vicious tripod-bound invaders in The War of the Worlds came from Mars. Where else could they come from? And a slew of movies from the 1950s featured Martians.

But the pop culture fascination is underpinned by centuries of genuine scientific intrigue, notes Prof Pillinger.

"It has been scientifically fascinating. It has this strange orbit - when you look at it from Earth… it goes back one way [then] goes back the original way.

"When people realised what that was, that was the clue that gave astronomers the information to say that the Earth went round the Sun."

So Copernicus's Eureka moment came from Mars, just like the B-movie invaders.

"Mars plays a role in science fiction and popular culture, aliens from Mars, the War of the Worlds," says Mr Cooper.

"There have also been a lot of space missions. It has always been there in the public conscience. When we talk about searching for life, Mars is always top of the list. I wouldn't call it mania but there's definitely something that captures the fascination."

Developments like the recent discovery of methane, which probably indicates either volcanic activity or life, keep the Mars fascination stoked. And, then there's the belief that Mars suffered a catastrophic event that changed its atmosphere - and terminated possible life.

"If that is true, could the same thing happen to Earth?" asks Nasa spokesman Swayne C Brown. "That's one reason we send machines to the Red Planet. The next step will be humans."

But if you can't wait to be in the running for one such manned flight, and you are determined to see something on 27 August, Nasa suggests Jupiter might be a better bet.

BBC NEWS REPORT.