Cooma residents are putting up a vast range of theories on the cause of explosion-like bangs heard at night since May. Some are looking to the skies and saying the cause is solar flares, or 'skyquakes', or meteors, or the Southern Lights. However Professor Fred Watson says the bangs aren't coming from the skies.

Professor Watson, Chief Astronomer at the Australian National Observatory, says that 'there is no known scientific literature on anything you could describe as a 'skyquake'.

However, he says reports of solar activity causing noises are quite common in northern Scandinavia.

"There is anecdotal evidence that people hear noises during auroral displays . But sadly, once again, scientists have not been able to come up with any proof of that," he said.

Professor Watson said that there has been solar activity and Southern Lights (Aurora Australis) in the region.

However he said that the phenomena in Scandinavia came from far north of the Arctic Circle 'where the aurora borealis (Northern Lights) is right overhead'.

"So you are within 90 kilometres of the activity.

He said there is nowhere in Australia that replicates that situation.

"I would rule that one out as a likely source," he said.

However, something he said we do see in Australia are fireballs.

"If you've got a fireball, which is a very bright shooting star, one that lights up the whole sky, usually about 4 minutes afterwards there will be a sonic boom from that. They are really quite impressive because you hear this band that seems to come from nowhere," he said.

"But what you're talking about seems to be a much more regular phenomenon. Fireballs are relatively uncommon."

Meanwhile, there is no shortage of other theories, including: an electrical short on a power pole; a meth lab; apprentice plumbers with acetylene bombs; fireworks; pipe bombs; a car backfiring; a bird scarer, and an increase in baked bean consumption.