Explainer: What was the mysterious fiery object above North Canterbury?

North Cantabrians were rattled on Monday night after an unidentified blazing object shot overhead, leaving behind startled animals, a smoking trail and a "sonic boom".

The mysterious occurrence has led to wide-spread speculation as to its origin - including rumours of an alien visitation and a giant drone.

But there's a more prosaic explanation. Otago Museum director Dr Ian Griffin says the object was most likely a meteor.

"All the reports I've read say it was probably a meteor, although I can't rule out space junk," he told Newshub.

"In terms of space, just to the best of my knowledge, nothing was scheduled to come down."

Meteors are pieces of space rock that enter the Earth's atmosphere, becoming visible as they collide with the air molecules.

On a normal night viewers may see between two and four meteors per hour - however during a large meteor shower, stargazers can see up to 100 meteors in one hour.

"When they start entering it's five to 10 kilometres per second," Dr Griffin says.

"But they start slowing down as the atmosphere starts acting as a brake, the lights you see in the sky are it burning up.

"Because they move quite quickly across the sky, even if it's really low it wouldn't last minutes, it's tens of seconds at the most."

Images show the bright orange arrow shooting towards the horizon, leaving behind a thick black trail.

"The colours you see depend on what's going on depending on the composition of the rock. Sometimes they're even green," Dr Griffin told Newshub.

The object was seen from everywhere from Canterbury to Nelson. Dr Griffin says if enough people tracked the flight path, it might enable some people to work out if it landed.

"If it was quite low - and it sounds like it was because of the sonic boom - it might have passed over New Zealand and hit the ocean," he says.