KHON-TV

One witness described the UFO as "two little fireballs."

KEWALO BASIN, Hawaii — It's hard to draw a surfer's attention away from the next wave, but whatever was in the northwest sky Friday evening around 6:20 p.m. drew a crowd along Kewalo Basin and Ala Moana Beach Park.

Honolulu resident Peter Hollingworth said he saw two lights circling in the sky, about 45 degrees above the horizon. He said it looked like "two little fireballs with a stream behind it."

Video of one of the lights was recorded from a camera aboard KHON-TV's helicopter.

"Looked kind of like a shooting star, but it just kept going," Hollingworth said. "They changed directions a few times; at first it was coming in; then it turned; then it went out; then it came back in again."

Hollingworth was surfing with his 12-year-old son when the unexpected show began.

"I was a little concerned. I told him come over and sit with me; this might be the last surf session we ever have together because this thing's coming straight for Honolulu," Hollingworth said. "It looked deadly to me. It was kind of spooky."

So what was it?

The National Weather Service said nothing showed up on their radar at the time of the sighting, and the Federal Aviation Administration didn't report anything unusual.

The U.S. military conducted a missile defense test off the Kauai coast on Friday evening, but the test didn't begin until 7:20 p.m.

"This, in a sense, is an unidentified flying object," said University of Hawaii astronomy professor Gareth Wynn-Williams. "It's something in the sky that's moving that we haven't identified."

Wynn-Williams believes there's a simple explanation behind the UFOs.

"It's probably a contrail of some kind," he said while watching video of one of the lights at his Kailua home.

The professor said contrails are caused by high-flying airplanes burning hydrogen-based fuels. One of the byproducts of the fuel exhaust is water.

"The air is very cold, so the water condenses and forms drops very quickly; they evaporate," he said.

Wynn-Williams doubts little green men from Mars are behind the UFOs.

"Some people just think differently than scientists, and they like to look for the fanciest, most exciting explanation," Winn-Willisma said. "Those people would like to think it's little green men. I think that's very unlikely."

According to published reports, this is not the first time a UFO has grabbed the attention of Hawaii residents.

In December 2004, an unexplained streak of light was captured by a camera on Haleakala moving southwest to northeast. No official explanation has been given for that UFO, either.