Telescopes are selling so fast there's a shortage at many stores. Great. Go out, gaze heavenward and soak up some red light from our planetary neighbor during this historical event.
But don't kid yourself. The dusty world you'll see remains more mysterious than a North American power grid.
A history of false impressions
Admittedly, a lot has been learned since the days when Mars was roundly feared by the masses. The idea that Mars was criss-crossed with canals, for example -- inaccurately popularized by astronomer Percival Lowell in the early 1900s -- turned out not to be true.
Lowell's assumptions built on observations during a close approach of Mars in 1877 -- similar to the one this year but not as close -- and a bogus language translation.
A History of False Impressions | | 
H.G. Wells 1898 book was rooted in the scientific hype of his day.
IMAGE: NASA
1698: Dutch astronomer Christiaan Huygens publishes Cosmotheros, one of the first publications to speculate about intelligent extraterrestrials. 1784: Sir William Herschel writes that dark areas on Mars are oceans and the lighter areas are land. He speculates that Mars is inhabited by intelligent beings who "probably enjoy a situation similar to our own." 1854: William Whewell concludes Mars has seas of green and land of red, and wonders if there is extraterrestrial life.
1858: Angelo Secchi, a Jesuit monk, draws Mars and calls Syrtis Major the "Atlantic Canal." He later writes that he was persuaded by the example of Earth that the "universe is a wonderful organism filled with life." 1860: Emmanuel Liais suggests that dark regions are not seas, but rather are vegetation tracts. 1867: British astronomer Richard Anthony Proctor publishes a map of Mars with continents and oceans. 1873: French astronomer Camille Flammarion attributes Mars' reddish color to vegetation. 1877: Giovanni Schiaparelli uses the term "canali," meaning channels, to describe streaks on the surface of Mars. The term is translated to "canal" in English.  1894: Percival Lowell begins observing Mars at his observatory in Flagstaff, Arizona. The next year he publishes "Mars," with drawings of the canals and speculation about their artificial origin.
1898: Inspired by Lowell's ideas, English writer H.G. Wells publishes "The War of the Worlds," a novel about a deadly invasion of Earth by Martians. 1908: Lowell writes "Mars as the Abode of Life," presenting his full theory that canals were built by smart folks. 1921: Guglielmo Marconi, inventor of the wireless, claims to hear signals that might be Martian. The next year and again in 1924 -- at times when Mars is relatively close -- radio stations observe silence, at the request of the U.S. government, so Mars transmissions can be heard. 1938: Orson Welles' Halloween radio broadcast of the fictional War of the Worlds, based on the H.G. Wells book, fires fear among thousands of Americans that Martians had landed in New Jersey. 2003: Mars comes closer to Earth, by a smidgen, than ever in recorded history. Rumors float around the Internet that the event will cause doom and destruction on Earth, proving that some things never change. -- Robert Roy Britt, SPACE.com
SOURCE: NASA and other reporting
Mystery Monday, a new feature on SPACE.com, appears weekly. | | | |
In late 1877, colorblind but sharp-eyed Italian astronomer Giovanni Schiaparelli studied Mars through an 8.75-inch (0.2-meters) telescope. Schiaparelli drew and wrote about canali, an Italian word meaning channels. The word was translated to "canals" in English. The goof was fueled, historians say, by excitement over the construction of the Suez Canal, an engineering marvel of the era completed in 1869.
Lowell later observed the same apparent streaks, which connected dark areas thought to be oases, and determined they were canals built by intelligent beings to irrigate the desert planet with water from the polar caps.
Lowell presented his first drawings in an 1895 book titled "Mars." He argued his full theory in a 1908 book, "Mars as the Abode of Life." Many newspaper editors of the time defended him, even though other astronomers withheld judgment.
In hindsight, Lowell's claims of intelligent life on Mars were outlandishly speculative. But his conclusions joined a chorus of false impressions about Mars that predated him by centuries and lasted well beyond his death in 1916.
As late as 1924, earthlings listened for radio signals from Mars -- at the request of the U.S. government. And in 1938 Orson Welles' radio antics frightened thousands of listeners into believing Martians had invaded, first targeting New Jersey.
Enduring tunnel vision
Nowadays we know the canals don't exist and that there are no invading forces, of course. Scholars say the canals were the product of a human tendency to see patterns. When looking at a group of dark smudges, the eye will tend to connect them with straight lines.
Mars harbors no oases, either.
Observations over the past two years have revealed, though, that Mars is loaded with frozen water, locked away at both polar caps and in the soil around much of the rest of the globe. But fresh observations of Mars have a habit of fueling new speculation and generating additional frustrating questions.
Hamstrung by robotic tunnel vision, scientists still don't understand the real Mars. They don't know if there is liquid water or life on the most Earth-like planet available for in situ scrutiny.
Despite an onslaught of up-close observations spanning nearly 40 years, the red planet hasn't given up its most coveted secrets.
Mariner 4 flew by Mars on July 14, 1965, snapping the first close-up photographs of another planet. Hopes of obvious plant or animal life on the surface endured. The Viking landers scooped soil and sent pictures from the surface starting in 1976, dispelling any notions of rampant biology on Mars. Hope turned to merely finding water and signs of microbial life.
Pathfinder landed on the red planet in 1997 and sent a high-tech rover, Sojourner, out scouting. The pictures were great. The mysteries remained.
There are two sophisticated automated probes orbiting Mars now. NASA's Odyssey and Mars Global Surveyor orbiters have clinched the case for widespread water ice, but all known sorts of organisms need the melted variety, and no amount of sleuthing has turned up a drop.
Experts say the most recent Odyssey data reveal there is more ice in the soil of Mars than they can explain given the best theories about the past and present climate of Mars.
"It's really a huge amount of ice," says William Boynton, a University of Arizona researcher on the Odyssey team.
The next round
The search will heat up later this year when Europe's initial foray to Mars -- the first of three landing craft now en route -- is due to arrive at Mars.
Early next year, arrival is planned for a pair of NASA rovers that would make George Jetson jealous, what with their full suite of geologists' tools, chemistry sniffers, navigation computers and panoramic cameras.
Even the Japanese are in the quest now, with an orbiting craft that is limping its way Marsward.
But will these remote eyes, alloy hands and computerized brains solve the greatest mystery in the human mind by discovering that terrestrial life is not unique in the cosmos?
Unlikely.
Capable as these machines are, they're not designed to uncover anything that might pulse with life, because such a thing on Mars is surely tiny and likely buried under the surface, where things are warmer, radiation-free and perhaps wet.
Elusive water
The robots might detect liquid water in the months to come, but even that is far from a given.
A team led by Michael Malin of Malin Space Science Systems, using Mars Global Surveyor, announced in 2000 strong evidence for water flowing recently down Martian cliffs. Other scientists are not so sure what the pictures showed.
Malin himself was cautious. "This story, I don't believe, will be answered until someone goes to one of these cliffs with a pick and shovel and digs into it," he said in 2000. So far, no automaton has proved him wrong.
Any discovery of firm signs of biological activity will probably have to wait at least until the end of this decade, possibly much longer.
NASA's Phoenix mission, slated for to land in 2008, will dig into the soil, stick some in an onboard oven, and try to learn if Mars might be habitable.
"Periodic variations in the Martian orbit allow a warmer climate to develop every 50,000 years," explains Peter H. Smith of the University of Arizona Lunar and Planetary Laboratory. "During these periods the ice can melt, dormant organisms could come back to life, (if there are indeed any), and evolution can proceed. Our mission will verify whether the northern plains are indeed a last viable habitat on Mars."
The mission is not expected to find actual organisms, but it could detect organic molecules that would hint at present or past life.
Many scientists believe the question of life on Mars won't be answered until humans are sent to investigate.
Other mysteries
Meanwhile, other intractable Martian enigmas are less widely discussed but just as puzzling to scientists in particular fields.
Arizona State University's Joshua Bandfield wonders about Mars from a geologist's perspective. Last week, he and some colleagues suggested Mars almost surely has had some liquid water, in the past at least, but it might never have had oceans. That would dash hopes of many scientists who've long banked on standing water in the past as an initial incubator for Martian life.
Asked last week what is the greatest Mars mystery, Bandfield tossed out a narrower issue: Why are the planet's two hemispheres so different, he wonders. The southern one is dominated by ancient highlands. The north contains a lot of younger, low-lying terrain. Rocks in each hemisphere seemed to have formed by different means.
"We really don't have any clue as to why that happened," Bandfield said.
We do know, at least, that irrigation canals had nothing to do with it.
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