ball lightning over Canberra
© Youtube/Joanne Steen (screen capture)
A video appearing to show a strange light above Canberra during a storm was probably capturing "ball lightning", an astronomer has said.

The video uploaded to YouTube last night, claims to show a circle or donut-shaped light appearing in the Canberra sky during a storm.

Australian National University astronomer Brad Tucker said the red and green light which glowed faintly in the background was "characteristic of an aurora" however believed this time it was ball lightning.

"An aurora is when energy from the sun hits the earth's atmosphere, the energy rubs the earth's atmosphere with friction and charges the gas," he said.

"But the problem is there was no activity from the sun, it was cloudy, we can't see the aurora, so it doesn't really fit."


Dr Tucker said in this case, the energy to create an aurora probably came from the thunderstorm itself.

"The same activity that causes an aurora, can actually happen inside our atmosphere if you have a storm with a lot of electrical charge that is rubbing against the gases in our atmosphere, causing it to grow that green or red colour," he said.

"Sometimes, if you get a really interesting occurrence, you create something called 'ball lightning'.

"Normally lightning strikes up and down hitting the ground, but ball lightning is a weird thing where it appears as a ball explosion, sometimes it can even move around in the sky."

Ball lightning had been reported to occur "more often in Australia than elsewhere".

"[But] there are lots of weird natural phenomenon that happens everywhere," Dr Tucker said.

"In Norway there's this weird appearance that happens every Autumn for a few weeks that causes weird UFO lights, but the lights happen regularly like clockwork."

Dr Tucker said he felt fairly certain extraterrestrial creatures could be ruled out as the cause of the light.

"I don't think it's aliens," he said.

"It's always hard to discredit aliens, but I think they would probably visit somewhere more active than Canberra coming back from holidays.

"It's probably not Photoshop either. Everything kind of fits and it seems right.

"Someone probably just got lucky, back from the holidays a little bit bored and saw an interesting storm, it's the only interesting thing going on in Canberra right now."

Forecaster Sean Carson said while he was speculating, he agreed that the light could be ball lightning.

"It's pretty amazing, no doubt about it," he said.

"There were obviously thunderstorms at the time, so lightning is all I can think of."

The ABC has contacted the person who uploaded the video to YouTube for comment.

Youtube video posted by Joanne Steen shows the event with slow motion footage included: