UFO EXPERT Sheryl Gottsthall hasn't come any closer to identifying what flew over the Gladstone region last night - but she has ruled out some theories.
Ms Gottshall, president of UFO Research Queensland, has investigated plenty of these cases before and she said the formula for finding the truth is ruling out possibilities.
"With UFOs, we have to go through the list of possibilities and tick them off," she said.
"If someone says it's a meteor, we have to tick that off."
And Ms Gottshall said the theory that it's a meteor just "doesn't gel" because "meteors don't rumble for five minutes", as one reader reported hearing.
She said while some readers reported seeing debris flying off the object, "if it was a plane crash --- a plane crashing and exploding --- you'd expect all sorts of emergency services to be arriving".
As for the theory of the air force's KC-30A carrying out an operation over Gladstone, "it could be jets, but I mean, it's really hard to tell".
UFO Research Queensland has received more than 5000 reports of UFO sightings since it was established in 1956.
And Ms Gottshall said interrogating witness accounts is the only way of getting closer to the truth.
"It's about getting a better description of what they saw --- the size, the speed, the distance, the colour, how they were affected," she said.
"What it was I really can't tell you. And in that respect it remains unidentified."
EARLIER: Was it the air force's KC-30A over the Gladstone region last night?
THEORIES of what was behind the bright light and the massive "boom" over the Gladstone region last night are running rampant.
Bundaberg Astronomy Society member Mark Sugars said descriptions of the sighting, which were reported from Rockhampton to Gympie, could suggest it was a meteorite.
But Gladstone's Rory Henricks said he thought he saw a plane, saying he thought it was "shooting fireworks out of its rear".
And Royal Australian Air Force watch keeper Corporal King has revealed that a bulk carrier KC-30A took off from the closest air base to Gladstone last night and is the only air force aircraft that could've been spotted in the vicinity last night.
Residents said the object, seen over the Gladstone region --- including Kirkwood, Calliope, Agnes Water and Tannum Sands --- made a "boom" sound around 9:20pm.
Corporal King, who couldn't reveal his first name because of strict defence force privacy protocol, said the KC-30A had taken off from the Amberley Air Base.
"It was the only aircraft that was flying from the Amberley area during that time," he said.
Amberley Air Base is 40kms south-west of Brisbane, on the outskirts of Ipswich.
Why the aircraft was in the area and what path it had taken remains a mystery, as corporal King said, "I'm not at liberty to disclose that information".
A KC-30A is a large aircraft described as "a heavily modified Airbus A330 airliner" on the air force's website.
It can also carry 34,000kg of cargo and 270 passengers.
The Observer is still waiting for the RAAF to explain what was behind the "boom" that was reported by residents.
KC-30A Multi Roll Tanker Transport Specifications