Distant lights seem to dance across the night sky. A glowing disc hovers above the treetops before—poof!—it disappears. An unusual object zigs and zags through the clouds like no known aircraft ever could.
Each year, thousands of people in the U.S. report seeing unidentified flying objects, better known as UFOs. Some people dismiss these claims as nonsense. Yet more than 40 percent of Americans believe that UFOs are alien spacecraft, according to a survey last year by the Gallup research company.
Do aliens exist? Or are there other explanations for UFO sightings? Even the U.S. government wants to find out. It has spent years secretly investigating the phenomena. But a report prepared last summer by the U.S. Department of Defense didn’t give many answers.
“[There] is something unknown in our skies,” says Ravi Kopparapu, a scientist at NASA’s Goddard Space Flight Center in Maryland. “We should be investigating it.
We should be collecting data and then try to understand what they are.”