At around 8:15 on the night of January 5, 2009, people across Morris County, New Jersey, started looking up.

Above the trees, there were red lights—five of them. They hung in a rough line, too steady to be planes and too bright to be stars. They seemed to drift and shift position. After a while they went out, one by one.

At 8:28 p.m., Hanover Township police took the first of several 911 calls. Neighboring departments got them too. A Morristown police lieutenant warned Morristown Airport about a possible hazard to aircraft; the control tower could see the lights but couldn't say what they were, and nothing showed on radar.

A Hanover Township family filmed them from home. The father, Paul Hurley, was a pilot. "I have been in the aviation industry for 20 years and have never seen anything like this," he said. "A little scary." Their video ran on cable news. The township's health officer, out walking his dog in Madison, said they couldn't be flares because they "did not leave trails," and that they seemed to move against the wind.

The lights came back on January 26, again on January 29, and on February 7 and February 17.

For about three months, Morristown had a UFO.

The two men in the woods

The "UFO" was five helium party balloons with a road flare hanging under each one.

Joe Rudy was 28, a science teacher from Chester. Chris Russo was 29, a salesman from Morris Plains. They'd gone into a patch of woods on the border between Morris Plains and Hanover Township, tied 15-minute road flares beneath the balloons, lit them, and let them go about 15 seconds apart.

On a cold, still night the balloons rose and spread into a loose chain. From miles away, with no balloon visible, what people saw was a formation of glowing red points moving slowly in unison. When the flares burned down, the lights went dark in the same order they'd been launched.

In their own write-up, they described their fingers being on the verge of frostbite.

Why they did it

Rudy and Russo said they weren't out for a laugh. They called it a social experiment.

They wanted to show how quickly an ordinary thing becomes extraordinary once enough people believe it—and how unreliable eyewitness accounts and self-described UFO experts can be.

And they played both sides. After the first launch, Rudy and Russo went on News 12 New Jersey posing as two of the witnesses. "We were driving on Hanover, when all of a sudden we see these lights literally zip over our car," Russo told the reporter. Rudy described the lights rising and dipping "almost in a sequence."

The police had actually guessed right early: Morristown's police said the lights were most likely road flares on helium balloons. A lot of residents refused to accept that. One man told the Daily Record the L-shaped formation he saw "didn't seem man-made," and that there was "no way this could have been weather balloons." The director of the National UFO Reporting Center told News 12 he didn't believe it was an aircraft.

Rudy and Russo filmed their launches and kept records. Then they took it public.

April Fools'

On April 1, 2009, the Skeptics Society's newsletter eSkeptic published Rudy and Russo's account of exactly how they'd done it, with their own photos and video. The date was a choice. It also guaranteed that a lot of people didn't believe the confession either.

That same week the story ran as news: the Morristown UFO was a hoax.

Morris County Prosecutor Robert Bianchi wasn't amused. Lighted objects floating at night near airports and homes, his office pointed out, were a hazard to aircraft and a fire risk. The two men were charged.

On April 7, 2009, Rudy and Russo pleaded guilty to municipal ordinance charges of disorderly conduct before Judge Michael Carlucci. Each was fined $250 and given 50 hours of community service, to be served with the Hanover Recreation Commission.

What it actually proved

It's tempting to file this under "case closed," and in the narrow sense it is. We know what the lights were, who launched them, from where, and how.

But what makes Morristown worth remembering is what it showed about everybody else. Many people saw something real: actual lights, in the actual sky. What they added—speed, formation flying, movement against the wind, something that "didn't seem man-made"—came from their own heads. A pilot and a public health officer vouching for it made it more believable, not less. The one official who'd guessed the boring answer was ignored.

Documented: Five-balloon, five-flare launches on at least five nights in January and February 2009; the April 1 eSkeptic confession; the April 7 guilty pleas, fines and community service.

What it suggests: Some other famous "light formation" sightings could have similarly mundane explanations. It doesn't prove all of them do.

So the next time you see a viral video of glowing lights in a row over a town, ask the boring question first: could two guys with balloons do this?

In New Jersey, in 2009, two guys did.

The Short below shows how the lights looked from the ground. Have you ever seen lights in the sky you couldn't explain? Tell us in the comments.