A strange object spotted by residents in the skies above Birżebbuġa on Saturday night could have been a "very bright meteor", also referred to as a fireball, according to the Astronomical Society of Malta.

It has attempted to shed light on the outlandish sighting, described by curious resident Charles Caruana as resembling a "hot air balloon" because it was clearly on fire.

Mr Caruana, who filmed the sight, said it advanced at speed from Żurrieq and over the water polo pitch towards the Freeport until it disappeared in the distance within minutes.

It was about 9 p.m. when he caught sight of it and zoomed off to get hold of his camera, saying it was the size of a car and was neither too high nor too far.

Mr Caruana excluded that it was a flying saucer because it was alight, but was still curious to know what it was. His curiosity was not satisfied when he went to buy the newspapers the next day.

Perhaps the most "extraordinary" observation, in Mr Caruana's view, was that it was not simply rising through the air but "zipping" and "dancing" at speed. Had it merely been an object that caught fire, rising slowly into the sky, Mr Caruana, who does not have particular extraterrestrial interests, would not have thought much of it. However, as it were, the unusual sight was more suspicious than pleasant.

The fire could be deciphered from when it was spotted over Żurrieq, but the possibility that it was a plane ablaze was quickly ruled out.

Although the only image the society had at its disposition to determine the nature of the object was out of focus, its president, Alexei Pace, said it could be deduced from the description that it was a fireball.

Meteors were caused when specks of rocks from outer space entered the earth's atmosphere at high speed and burned up to produce the streak of light that was called a shooting star, Mr Pace explained.

The recent Perseid meteor shower, the famous Tears of St Lawrence, peaked on the night of August 12, he pointed out.

"Fireballs are caused when a larger object enters the atmosphere and burns up spectacularly. It often takes several seconds to disintegrate and, often, it does not burn up entirely because it is too big, ending up on the surface of the earth as a meteorite," Mr Pace explained. "In this case, it seems this did not happen. It appears the rock from outer space simply burned up in the atmosphere."

Avid observers of the night sky, the members of the society have witnessed several of these fireballs and "each one remains vivid in our memories". Sometimes, they change colour as their various components burn up separately. On other occasions, they can break up during entry, or even explode at the end.

Mr Pace was "fairly confident" something similar had been observed by Mr Caruana. His only scepticism lay in comments on its size or that it zipped through the sky. He said these were subjective and did not really tally with a scientific explanation.