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 and a bogus language translation.
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.
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.
Timeline of Martian science and lore
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.
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.
2005: Discoveries of submerged icebergs and atmospheric methane refuel speculation of microbial life.
2005: A hoax circulates the Internet, stating that Mars will be as big as the full Moon, proving that some things never change.
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