Between about 8 and 10 o'clock on the night of March 13, 1997, hundreds of people near Phoenix reported spotting mysterious clusters of lights in the sky. A number of witnesses said that many of them seemed to come from a brightly lit, V-shaped craft, the size of at least several football fields.
"It was astonishing, and a little frightening," one local resident said. School administrator Susan Watson still remembers watching with her children as the massive object she describes as a "floating" city passed silently over their home. Air National Guard spokesmen later suggested the witnesses may have seen military flares that were dropped that night, while some proposed that observers were confused by aircraft flying in formation. But these explanations left many unsatisfied, particularly one witness who, for a decade, was reluctant to acknowledge he had also seen the vehicle: Fife Symington III, Arizona's governor at the time.
"I'm a pilot, familiar with most aircraft," Symington now says, "and what I saw is nothing like I've had any knowledge of."
Thousands of unidentified flying objects are reported each year by the public. The fascination with UFOs has become a fixture of contemporary culture and a staple for science fiction writers and supermarket tabloids. But in response to the central question—are they alien spacecraft?—most officials and academics dismiss the idea of extraterrestrial visitations as unlikely in the extreme.
Yet an increasing number of researchers and public officials say the subject of UFOs is long overdue for more serious treatment. They're a "mystery that science needs to engage in," argues journalist Leslie Kean, who spent over a decade interviewing former military officers, government officials, scientists, and eyewitnesses while accessing previously classified government records for her 2010 book UFOs: Generals, Pilots, and Government Officials Go On the Record.
Generally, a UFO is defined as a phenomenon in the sky—be it a light, solid object, or a combination of these—whose true nature or source can't be determined. Those who study UFOs say that some 95 percent of sightings can later be explained as ordinary man-made objects or naturally occurring phenomena, from flares and military aircraft to weather oddities or reflections of the planet Venus. But that still leaves about 5 percent that seem to defy rational explanation.
"The bottom line is we don't know what they are," says Kean, a former broadcast radio producer and veteran investigative journalist who has contributed to publications like the Boston Globe, the International Herald Tribune, and The Nation.
The public's fascination with UFOs is a modern expression of an age-old enchantment with remarkable events in the skies, notes Albert Harrison, professor emeritus of psychology at the University of California–Davis and author of the 2007 book Starstruck: Cosmic Visions in Science, Religion, and Folklore.
"Signs from the gods, omens, and portents have been replaced by space-age visitors that have remarkable god-like qualities and power," he says.
It wasn't until after World War II that interest in space-age visitors—and UFOs—really seemed to take off, and then it did so in a spectacular way. On June 24, 1947, salesman Kenneth Arnold was flying his private plane near Mount Rainier in Washington when he spotted a chain of nine, brightly lit objects moving at incredible speed near the mountain's peak. Arnold described each of them moving "like a saucer would if you skipped it across the water," ushering the phrase "flying saucer" into common parlance. As with many such sightings, various explanations were offered—a mirage or meteors, for example—but in the eyes of many people the mystery was never resolved.
Public interest in UFOs continued to grow in the 1950s and '60s as the idea of manned spaceflight to other worlds led many people to imagine what—or who—might be traveling the other way. As reports of UFOs proliferated, media coverage seemed to inspire even more reports. Concerned about potential threats to national security, the government began to investigate. Its most notable program, the Air Force's Project Blue Book, began in 1947 and involved the analysis of some 12,600 UFO reports over two decades, most of which were categorized as misidentified natural or man-made objects, such as weather balloons or high-speed aircraft. By the end of 1969, the Air Force declared that none posed a threat or involved an extraterrestrial vehicle. The project's leaders did acknowledge, however, that they could not come up with an explanation for about 700 of the incidents.