There's no official explanation yet of what people reported in the skies over Detroit last Thursday night.

"I've been watching the airplanes tonight and it wasn't quite as high as them," eyewitness David Levy told Fox 2 News. "You could actually see the triangle shape of the object."

Levy was with a group of friends in Flat Rock around 9:30 p.m. on Jan. 10, according to Fox 2 News reporter Ron Savage. "In fact, our Fox 2 Facebook page has been blowing up with hundreds of posts on the subject," Savage reported.

One Facebook poster named Shaun wrote: "They were black triangle-shaped objects making circles over West Bloomfield and Farmington Hills. There was no noise and they had bright lights. I'm not making this up and I know somebody else saw these things."

Watch this Fox 2 News report about the Detroit UFOs

During the Fox 2 report, news anchor Huel Perkins said, "For years, the Air Force conducted an investigation of so-called UFOs. They found no official proof."

Was he referring to the Air Force's famous Project Blue Book, which ended a two-decade-long study of UFOs in 1969, concluding that five percent of the cases -- approximately 700 sightings -- investigated could not be easily explained away? What did Perkins mean when he said the Air Force "found no official proof"? Proof of what?

While Detroit-area observers wondered what those triangular shaped aerial objects were, also on Jan. 10, almost 20 miles north of Detroit, in Warren, Mich., an equally puzzling object was recorded on video.

As reported by Latest UFO Sightings, the bright lights on this object turned on and off, as it went through a variety of shapes, including a triangle.

Check out this UFO seen over Warren, Mich.

Michigan was home to one of the most infamous of all UFO sightings in history. In 1966, while he served as the official Air Force scientific advisor to Project Blue Book, astronomer J. Allen Hynek declared that a UFO sighting in Dexter, Mich., was probably caused by "swamp gas," a term that would haunt Hynek for the rest of his life, and one which has often been cited around the world since then.

Hynek's swamp gas theory even angered then-Michigan Congressman (and future president) Gerald R. Ford, who said in a 1966 radio broadcast, "I believe Congress should thoroughly investigate the rash of reported sightings of unidentified flying objects in southern Michigan and other parts of the country.

"I feel a congressional inquiry would be most worthwhile because the American people are intensely interested in the UFO stories, and some people are alarmed by them," Ford said.

Almost 50 years later, not much has changed.

Swamp gas, balloons, lanterns, meteors, secret military aircraft? Most UFOs end up easily explained:

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• Changing UFO Pattern -- Warren, Mich. 1-10-13

  This four-image series of lights in the sky was recorded over Warren, Mich., on Jan. 10, 2013. The lights were seen changing into several patterns. The most common explanation for these types of UFOs is a series of balloons or lanterns.

• UFOs Over Earth

  This composite image shows four different times that alleged UFO were photographed above Earth by either space shuttles or the International Space Station. The big question is whether or not they are truly unidentified objects or if they are more likely reflections from spacecraft windows, meteors or fast-moving spacecraft-generated debris.

• Exploding Weather Balloons, Not UFOs

  On Dec. 20, 2012, a bright, circular object (pictured at the top of this composite image) was videotaped exploding in the skies above Sacramento, Calif. It wasn't immediately identified, resulting in speculation that it was either an alien spacecraft, military top secret weapon, runaway planet, North Korean satellite, among others. Within a short period of time, it became apparent that this was a weather balloon. The bottom part of this image shows such a balloon as it ascended over Tampa Bay, Fla., on July 2, 2012, and exploded in an identical manner as the Sacramento object, probably much to the dismay of all true ET believers out there.

• Pink UFOs Or Lens Flares?

  What appear to be pink-red UFOs are actually lens flares from the Google Earth street view camera as it snapped images in Texas (left) and New Mexico (right).

• Lens flares Arizona

  These two flying saucer-shaped, pink-colored lens flares were created by the Google Maps camera as it drove through locations in Sedona, Ariz. (left) and Flagstaff, Ariz. (right). The images were snapped in April 2009. Submitted to HuffPost by trenna.

• Lens flare Whiteriver, Ariz.

  This skybound lens flare was created by a Google Maps camera in June 2008 over Whiteriver, Ariz. Submitted to Huffington Post by Cheryl Weeks.

• Lens flare Gulfport, Miss.

  This very Earthbound lens flare was created by a Google Maps camera in November 2007 at Gulfport, Miss. Submitted to Huffington Post by Jenni Parker.

• Lens flare Eureka Springs, Ark.

  This seemingly grounded lens flare was created by a Google Maps camera in January 2008 at Eureka Springs, Ark. Submitted to Huffington Post by SE.

• Lens flare Escanaba, Mich.

  This lens flare appears to be following a car. The Google Maps image was created in October 2008 at Escanaba, Mich. Submitted to Huffington Post by Mary Robinson.

• Lanterns

  These candle-lit Chinese lanterns can rise high into the sky and were mistaken for UFOs in England.

• Boomerang UFO composite images -- 10-5-12

  This is a composite of images shot by two eyewitnesses of a boomerang-shaped UFO they reported seeing over their Burbank, Calif., home on Oct. 5, 2012. Mutual UFO Network photo/video analyst Marc Dantonio concluded the object was likely "a balloon, floating on the wind that has collapsed in half."

• Cincinnati Skydivers NOT UFOs Sept. 28, 2012

  On the night of Sept. 28, 2012, a group of strange-looking lights appeared in the sky near Cincinnati, Ohio. First there was one, then, two, then three lights, slowly descending. It turns out, however, that these lights were originating from a group of skydivers performing a pyrotechnics jump at the La Salle High School homecoming event.

• Weather Phenomenon

  Some UFO sightings may be due to a natural phenomenon known as sprites, like this one shown from 2006. "Lightning from [a] thunderstorm excites the electric field above, producing a flash of light called a sprite," said geophysicist Colin Price.

• Clouds

  Clouds: Saucer-shaped or "lenticular" clouds that form at high altitudes have been confused with UFOs.

• Blimps or Advertising Balloons

  Blimps or advertising balloons: These can look like flying saucers from some angles, especially at night.

• Sunken Ship in the Baltic Sea

  On June 19th the Swedish-based diving company Ocean Explorer discovered something they've never quite seen before. They were exploring in the Baltic Sea between Sweden and Finland looking for sunken treasures when a very unusual image suddenly appeared on the sonar. A 197 feet diameter cylinder shaped object was discovered at the depth of approximately 275 feet which resembles the Millennium Falcon from the movie Star Wars.

• Baltic Sea UFO 1

  An image released on June 15, 2012, shows a close-up view of the unidentified object sitting on the bottom of the Baltic Sea.

• Baltic Sea UFO 2

  Close-up of rock bed that forms the Baltic Sea UFO, which still mystifies researchers.

• Baltic Sea UFO 3

  One of several odd stone circle formations, sitting on top of the unidentified object at the bottom of the Baltic Sea.

• Antarctic UFO -- Aug. 10, 2012

  A circular UFO hovers above the Neumayer-Station III research facility in Antarctica on Aug. 10, 2012. Theories ranging from a simple weather balloon to a more elaborate ship from another planet have run the Internet gamut. The next slide shows a closeup of the object.

• Antarctic UFO Closeup -- Aug. 10, 2012

  This is a closeup of the UFO from the previous slide. No official explanation has been offered about the object.

• Manufactured UFO -- 2011

  Pictured is a quad copter -- a deliberately manufactured UFO created by special effects wizard Marc Dantonio for a National Geographic special, "The Truth Behind: UFOs," which aired in December 2011. On the left is what the small device looks like resting on the ground, measuring 4 feet in circumference. At right, is how it appeared behind a tree in the night sky.

• Police Dashboard Camera In Texas

  In February of 2012, this fireball was captured by a Texas police chief's A dashboard camera. F.A.A. say this was probably a meteor, falling to Earth. .

• Meteors

  Meteors: Space debris can create a spectacular light show when it burns through the Earth's atmosphere, and sometimes reported as UFOs.

• Civilian or Military Aircraft

  Civilian or military aircraft: Planes can look mysterious at night or in certain light conditions, thus confusing an observer.