More than 3,000 reports of unidentified flying objects were sent to the National UFO Reporting Center over the past year - but not one has generated as much buzz as November's sighting at Chicago's O'Hare International Airport. Was it a metallic-looking, saucer-shaped object rising through the clouds, or nothing more than a meteorological oddity? It's hard to figure out whether the truth is really out there, but one thing is for sure: Clouds can do some positively alien-looking things.
Peter Davenport, the UFO center's director, says the buzz over the O'Hare sighting is fully justified.
"In my opinion, because I know the quality of the witnesses, and because I know the nature of the documents that were generated, it is one of the most dramatic cases of the year 2006 that this center has handled," Davenport told me today from the center's headquarters in Washington state.
On the other side, NBC News space analyst James Oberg - a longtime UFO skeptic - says the evidence that's come to light so far isn't all that compelling.
"It's just sad that we keep getting these reports which are of zero evidential value," he told me. "It's sad because there's a lot of strange stuff in the air that we do need to know."
Davenport's center put out the first reports on the O'Hare sighting weeks ago, but the report really picked up traction over the past weekend, when The Associated Press picked up a Chicago Tribune story about the case (free registration required).
Here are the basics: Employees at O'Hare reported seeing a dark gray, seemingly spinning disc hovering above Concourse C - at an estimated altitude of hundreds of feet, close to the cloud cover. The disc appeared to fly up at a rapid rate, leaving behind a hole in the clouds.
The Federal Aviation Administration acknowledged that it received a sighting report, but agency spokeswoman Elizabeth Isham Cory said no further follow-up was planned.
"Our theory on this is that it was a weather phenomenon," she told the Tribune. "That night was a perfect atmospheric condition in terms of low ceiling and a lot of airport lights. When the lights shine up into the clouds, sometimes you can see funny things."
Case closed? Not so fast, Davenport said.
"I am certain that the airline and the FAA are now attempting to conceal the true nature of the incident," Davenport said.
So far, about a dozen witnesses - all affiliated with the airport or airlines - have surfaced, according to the Tribune. Davenport said he's not yet aware of any reports from outsiders.
"Trying to find the actual eyewitnesses is very difficult," he said. "My suspicion is that there are a great many more. ... You ask, are there other witnesses? My response is, almost certainly. How do we find them, and how do we get them to come forward?"
One of the airport witnesses did take a photo of the phenomenon, but is reluctant to make it public out of concern for his job, Davenport said. "So far, over almost two months, we've been unable to get that," he said.
I have a feeling that even photographic evidence wouldn't settle the case. There are so many weird atmospheric phenomena out there that even crystal-clear pictures could be interpreted either as UFOs or as cloud patterns. For example, check out this roundup of lenticular clouds (offered with a big tip o' the Log to Phil Plait's Bad Astronomy Blog). Even knowing what they are, you'd be hard-pressed not to see them as flying saucers worthy of a Steven Spielberg blockbuster.
The idea that the disk left a hole in the clouds might sound like an atmospheric vortex phenomenon - perhaps like the vortices created when airplanes zoom through clouds. This Web page includes a video of an airplane leaving a dark, indistinct vortex in its wake. Other weird phenomena are reminiscent of smoke rings.
When I suggested that the O'Hare incident might have been a vortex created by an airplane rising through the clouds, Davenport shot me right down.
"You can conjecture all day long on that point if you wish to do so, but it's futile in this case," he said. "First of all, airplanes don't fly over [terminal] gates, they fly over runways. So your surmise, I think, is not appropriate in this case. ... This object was seen by many people to accelerate so fast and go straight up in the clouds that their eyes were unable to follow it."
To be fair, Davenport's center has been taking such cases seriously for 32 years - longer than I've been a professional journalist. So who am I to question the reports, particularly when they seem so authoritative?
The O'Hare incident is being taken more seriously than most sightings because the reports are coming from aviation professionals rather than untrained onlookers. But Oberg argues that the professionals don't always make the best eyewitnesses because they tend to favor flight-related explanations for what they see.
"NTSB investigators say that the worst observers of an aviation accident are aviation personnel," Oberg said. "It's because a pilot will usually want to understand what happened, and in his initial perceptions and later retellings will stress the facts that support his initial interpretation."
Oberg pointed to a couple of case studies in pilot misperception, investigated in detail years ago. And just for good measure, he passed along Web links to a Russian UFO report from 2001 that sounds similar to the O'Hare incident, plus the solution to a UFO mystery that came up just last week in Europe.
Oberg said the European case was particularly instructive, because the specifics about the mysterious glow in the sky helped investigators quickly figure out that it was most likely a cloud trail left behind by a Russian rocket launch. Without such specifics, the O'Hare incident may turn out to be little more than another "missed opportunity," Oberg said.
In any case, the incident is making for an interesting tale, and that has led Cosmic Log correspondents to add more UFO tales to a posting I published back in June. Feel free to offer up your own story right here in the comments section, even if it's decades old. If you've got a recent sighting, you might want to let Davenport know as well - you can find the contact details at his Web site.