MELISSA BLOCK, HOST:
This is ALL THINGS CONSIDERED from NPR News. I'm Melissa Block.
AUDIE CORNISH, HOST:
And I'm Audie Cornish. On a spring evening earlier this year, some residents of Fairbanks, Alaska picked up a mysterious signal.
(SOUNDBITE OF BEEPING)
CORNISH: It was followed by eerie music.
(SOUNDBITE OF EERIE MUSIC)
CORNISH: It came from a remote Air Force research facility 200 miles away. The facility is used by scientists to study the very edge of the Earth's atmosphere, and over the years it's become the subject of countless Internet conspiracies. NPR's Geoff Brumfiel reports both the research and the conspiracies may soon come to an end.
GEOFF BRUMFIEL, BYLINE: Well, it sure looks suspicious. A fenced-off military compound filled with nearly 200 weird-looking antennas, each several stories tall, in the middle of nowheres-ville, Alaska. It's called HAARP, the High Frequency Active Auroral Research Program.
DENNIS PAPADOPOULOS: I was giving an interview at HAARP, and the reporter said HAARP is number five on the Internet conspiracies, following the Kennedy assassination, which is number four.
BRUMFIEL: Dennis Papadopoulos is a physicist at the University of Maryland. He uses HAARP for his research. He's heard all the conspiracies.
PAPADOPOULOS: Using HAARP, you can change the weather. You can do all kinds of things.
BRUMFIEL: Just Google it - HAARP with two A's. You'll see what it can do.
UNIDENTIFIED MAN: Disrupt human mental processes - jam all global communications - interfere with wildlife migration patterns...
BRUMFIEL: Trigger earthquakes - spark tsunamis - the list goes on and on. But the real reason HAARP exists is less exciting.
PAPADOPOULOS: We are studying the region through which all the signals, from satellites to your TV and GPS, go through. And it's called the ionosphere.
BRUMFIEL: The ionosphere is at the very top of the Earth's atmosphere - the edge of space. It's filled with charged particles that respond to radio waves. HAARP studies the ionosphere by beaming radio waves straight up into it.
PAPADOPOULOS: It's like a radio station, but much more powerful.
BRUMFIEL: HAARP is even powerful enough to create an artificial aurora high in the sky. The research has the potential to improve satellite communications and navigation. And yes, the military has used it to study things they don't talk about.
PAPADOPOULOS: On occasion. There have been secret experiments.
UNIDENTIFIED MAN: Secret experiments for mind control?
PAPADOPOULOS: If we could do that, as I say, we'll patent it. (Laughing) We'll sell it to the world, straight.
BRUMFIEL: So much for that. And what about that unearthly music you heard at the beginning of the story? Actually, it's no mystery. It came from this guy.
CHRIS FALLEN: Chris Fallen - I am a research assistant professor at the University of Alaska Fairbanks.
BRUMFIEL: Since HAARP is basically a giant radio station, Fallen decided to try an experiment.
FALLEN: I was transmitting a musical performance that was composed by visiting musicians.
BRUMFIEL: He was testing something known as the Luxembourg effect. Put down that tinfoil hat, it's legit. When radio signals at different frequencies bounce off the ionosphere, they can mix together. Fallen split the music.
FALLEN: So one half of the performance was transmitted on 3.25 megahertz. And the other half of the performance was broadcast on 4.25 megahertz.
BRUMFIEL: The ionosphere blended the halves into a single song and reflected it back down to Fairbanks.
FALLEN: These two different musical performances were essentially mixed in space.
REPORTER: But Fallen's cosmic concerts and the other research is ending. The $300 million facility was originally built at the behest of a powerful former Senator from Alaska, Ted Stevens. Stevens died in a plane crash in 2010, and now the Air Force says it doesn't want to pay to keep HAARP open. So the facility is switching off, today. Unless independent scientists can find a way to save it, it will soon be bulldozed. It will vanish without a trace. That should give the conspiracy theorists something to talk about. Geoff Brumfiel, NPR News.