PETERSON AIR FORCE BASE, Colo. (AP) -- A spent Russian booster rocket re-entered the atmosphere Thursday over Colorado and Wyoming, the North American Aerospace Defense Command said.

Eyewitnesses reported seeing flaming objects in the sky at the time the rocket was re-entering, NORAD spokesman Lt. Cmdr. Sean Kelly said.

"It was pretty spectacular," said Riverton Police Capt. Mark Stone, who said he saw the burning object while he was retrieving his newspaper. "My first concern is that we had some sort of aircraft that was coming down. It was definitely leaving a burning debris trail behind it."

Stone said he could tell it was fairly large object, but it was too high to make out exactly what it was.

Kelly said the agency was unable to confirm a report that a piece of the rocket may have hit the ground near Riverton, Wyo., at about 6 a.m. MST.

No damage was reported, and any debris that may have hit the ground was not believed to be hazardous, NORAD said.

NORAD identified the rocket as an SL-4 that had been used to launch a French space telescope in December, and Kelly said U.S. spacewatchers knew the rocket was coming down.

"Objects falling from space are almost an everyday occurrence," Kelly said.

"No damage has been reported and the debris is not believed to be hazardous. It's also important for the public to understand that the reentry of pieces from this rocket is complete, so in other words, they're not expecting other pieces to fall," she said.

A U.S. Space Control Squadron at Cheyenne Mountain Air Force Station in Colorado Springs, Colorado, tracked the reentry of the spacecraft launched on December 27.

Typically 200 objects reenter the Earth's atmosphere every year, but the debris typically burns before it hits the ground and rarely falls in populated areas, Cunningham said.

While space debris might make for a unique souvenir, NORAD advises against handling any that may be found.

"We also encourage anyone who believes that they may know the location of a piece from this rocket to exercise caution and inform their local authorities immediately for potential recovery," Cunningham said.

Ahmad told Deutsche Presse-Agentur dpa that the beacon's signal was growing weaker as its battery came closer to exhausting, which would further hamper the massive land, sea and air search.

The Indonesian government has become so desperate to find the missing budget carrier flight, which disappeared on Monday, they have called in psychics and actually deployed search teams to locations that the paranormal experts suggested, but nothing was found.

"We are using a coordinates map and a psychic map, but neither has worked," Ahmad said.

Four Indonesian Navy warships carrying amphibious troops and divers were sent to Sulawesi Island to bulk up what has already been a massive operation, which on Saturday will expand further north and east of the large, octopus-like island.

The US is assisting by conducting offshore satellite imaging, and a Singaporean naval ship joined in the search on Thursday.

Adam Air flight KI-574 was carrying 96 passengers, including three US citizens, and a crew of six when it disappeared on Monday afternoon in bad weather.

Conflicting information hampers progress

Rescue officials are increasingly frantic about finding the plane, which senior officials had erroneously reported was spotted along with 12 survivors on Tuesday morning. The false reports delayed expanding the search into the Makassar Strait by at least one day and enraged grieving relatives of the passengers.

Military and civilian rescue teams have been hampered by inclement weather and are not equipped to search at night.

The response to the missing plane has exposed Indonesia's limited emergency response capabilities and bureaucratic incompetence. Officials had previously said the jetliner disappeared after issuing a distress signal, but they later admitted that there had been no distress call.

Government officials on Tuesday were forced to retract earlier statements that a crash site had been located in a remote, mountainous region near the town of Polewali Mandar, about 1 600 kilometres north-east of Jakarta, and that 12 people had survived while 90 bodies had been accounted for.

President Susilo Bambang Yudhoyono has ordered an investigation into the condition of all commercial planes in Indonesia, as well as an evaluation of the nation's transportation system.

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.

There was no thunder or lightning and the noise grew louder, eventually sounding like a million turbines screaming in unison, said Ras.

She walked to the bedroom window and saw the clouds taking on a bright orange-red colour.

She described the object as a bright object that "plunged from the clouds to the earth, at a terrible speed, and hit the ground with an almighty bang."

It looked like Haley's comet, "round in the front and with an orange-red tail following behind".

On Wednesday, the Lephalale police station reportedly received numerous enquiries following the incident.

But the area was vast and there was no way of knowing where to start looking, said Superintendent Wessel Geldenhuys.

He added that the object could have fallen in Botswana, which is situated about 45km away.

Geldenhuys said that Ras's neighbour had also seen the UFO, but that so far, no one else had seen the object or had any idea where it was.

"We have had many queries, but no answers," he said.

The observation could improve space weather forecasts, as well as help improve models of turbulent flow in ionized gas, called plasma.

Turbulence is quite common on Earth, as any frequent airplane passenger can attest. But even physicists get a little queasy when trying to explain the nature of this choppy, swirling flow.

"One cannot predict future behaviors with satisfactory accuracy," says Yasuhito Narita of the Institute of Geophysics and Extraterrestrial Physics in Braunschweig, Germany. "Even a small deviation or uncertainty in the initial state will end up with a completely different state."

Chaos reigns

It's a bit of the butterfly-tornado connection from chaos theory. Without predictive mathematical equations for turbulence, scientists usually resort to statistical descriptions, like how much does the pressure or velocity vary over a certain distance.

Researchers have done such detailed observations of the turbulence in wind tunnels and water pipes. Making similar measurements in space has been harder to do. Still, astrophysicists have inferred the presence of turbulence inside stars, among interstellar clouds, in black hole accretion disks and around Jupiter's red spot.

Single satellites have also studied the solar wind and have detected turbulent signals in the way this plasma flow changes with time. However, to make direct comparisons to models, researchers had to assume something about the size of wind variations.

Data cluster

To avoid this ambiguity, multiple sensors are needed to measure the wind's properties at several points. This is exactly what the Cluster suite of satellites was designed for.

"One needs at least four spacecraft to obtain the spatial resolution in three dimensions," Narita told Space.com. "Cluster spacecraft provide a minimal set of the measurement points for this purpose."

The four identical Cluster satellites orbit the Earth in a pyramid formation, collecting electric and magnetic field data. Of special interest is the Earth's protective magnetosphere, where the planet's magnetic field deflects the ionized solar wind, like air hitting a car's windshield.

A big shock

On Feb. 18 2002, the Cluster quartet ventured out into the leading-edge of the magnetosphere. At this bow shock, reverberating shock waves cause ripples and eddies in the solar wind propagation: a prime place to look for turbulence. Analyzing the magnetic field intensities recorded by each satellite, Narita and his colleagues were able to pinpoint changes in the wind speed. From this, they determined how the solar wind's energy varied over distance, as detailed recently in the journal Physical Review Letters.

The results largely matched energy fluctuations seen in Earth-bound fluid turbulence, making this the first "definitive" detection of space turbulence, said Melvyn Goldstein of Goddard Space Flight Center. He has worked on previous studies that gave hints of the same similarity.

That the solar wind behaves like the cream swirling in your coffee is surprising, since the low-density solar wind has almost no viscosity--an important component in fluid turbulence.

"For turbulence to develop in space, there must be some physical processes that can replace the role of viscosity," Narita says.

This viscosity replacement may be some complicated electromagnetic interaction between the solar wind's ionized particles. Goldstein says much of the current work is aimed at understanding how this plasma behaves in relation to the nearby magnetic fields.

Better characterization of solar wind turbulence could help scientists predict space weather, which affects the radiation level for astronauts and spacecraft, Narita says.