Five myths about Mars

No planet in our solar system has been linked to more misconceptions than Mars, where NASA's Curiosity rover is scheduled to touch down on Sunday night. Here are the five most persistent myths about the Red Planet.

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But Herschel did make the mistake of assuming that the dark areas he saw on Mars were oceans, broken up by lighter regions representing land. The idea of Martian oceans would persist throughout the 1800s. Close-up looks at the planet would prove it to be arid, though some scientists think liquid water once flowed on the planet billions of years ago. As of today, the water found on Mars has all been locked up as ice in the soil, with evidence of liquid water at the surface still uncertain.

In Pictures: Exploring Mars with Curiosity

Myth #4: Mars will appear as big as the moon

Since 2003, an email forward has circulated claiming that on a certain date Mars "will look as large as the full moon to the naked eye." For extra urgency, the writer warns readers, "NO ONE ALIVE TODAY will ever see it again."

No one alive today will ever see it at all, as it turns out. In fact, Mars' orbit did bring it close to the Earth on Aug. 27, 2003, but the planet looked only six times larger and 85 times brighter than it does normally — certainly not anything close to our view of the moon. [Album: Beautiful Shots of Mars]

This close approach in 2003 was the nearest Mars has been in 60,000 years at about 35 million miles (56 million kilometers). In comparison, the moon is, on average, 238,855 miles (384,400 kilometers) from Earth. Even given its larger size, Mars would have to get pretty close to match the moon in the night sky.

Myth #5: Mars supports intelligent life

The possibility of life on Mars isn't ruled out, but these days, scientists tend to look for tiny microbes, not super-smart tentacle-armed Martians.

The latter is the more common image when going back through the history of human imagination about Mars. Sir William Herschel, a great believer in extraterrestrial life, wrote in his 1784 paper that Martians "probably enjoy a situation similar to our own." The eventually overturned canal observations sparked widespread interest in the idea of an intelligent, perhaps ancient, civilization on the planet.

Perhaps the most famous Martian "encounter" was H.G. Wells' novel "The War of the Worlds," published in 1898. In 1938, a radio adaptation of the novel spawned panic when listeners assumed the invasion described was real. Who could blame them? Just 17 years before, the New York Times published an article declaring that the Marconi Wireless Telegraph Company, Ltd., had received transmissions from Mars too regular to be natural occurrences.

"Now this much is known about Mars," the NY Times quotes Marconi wireless manager J.H.C. Macbeth as saying. "Astronomers assert their belief that life can be sustained on that planet. Whether human life and whether Martians, if they exist, have eyes in their foreheads or the backs of their heads, of course, is speculation."