A "blinding" flash, intense explosion and sonic booms experienced over much of the country last night were probably caused by a meteor, experts agree.
About 10pm, the flash, described by many as a burst of blue and white light, was seen from Whangarei to the upper South Island.
WeatherWatch.co.nz, which has a dedicated meteors page, received dozens of comments.
"This was an exceptionally bright flash of light across the country, with many people saying they heard sonic booms that scared them and the animals," head weather analyst Philip Duncan said.
Data visualisation: Where meteorites fall
'Almost certainly extra terrestrial'
Meteorite expert and former publisher of Meteorite Magazine Joel Schiff said he did not see last night's event in person, but based on footage he had seen online it was "almost certainly some extra terrestrial material".
"It's either that or it's going to be space craft debris," he said.
He said he didn't believe it was a meteor, and called it a fire ball.
"Meteors are just those little streaks of light that people see every night of the week, they're just the size of a grain of sand and they come generally from comets. They have nothing to do with this episode.
"This is different, you would call this a fire ball, and when it lands on the ground it becomes a meteorite."
Mr Schiff said it would have been burning up as it entered the atmosphere, and that would have caused minerals in the object to show different colours like green and red."
It was hard to know where it would have made contact with the Earth's surface, or if it had exploded in the atmosphere, where any debris had landed, he said.
"They can explode in the atmosphere and rain down debris and if it happens to be over the land you're in luck. New Zealand is a narrow target and it depends on the path it was going and whether it went out to sea or broke up over land.
"You would need more sightings to determine the destination of it."
Mr Schiff said it was difficult to estimate the object's size, but it could be anywhere between a grapefruit and a basketball.
"It would have been travelling faster than a speeding bullet, that's why you've got the big flash and a lot of excitement... you hear these detonations, that's maybe breaking up and you hear these sonic booms."
Mr Schiff encouraged people to keep an eye out for black rocks.
"It was burning up and the outside of the body would have been charred black, and so if anyone was to find anything on the ground it would be very very black, pitch black, like barbecue black on the outside."
He said these rocks would pose no health or safety risks.
"They are not radioactive, they won't be hot. Immediately after landing on the ground they wouldn't be hot, there is no health and safety risk."
However, volcanic black rock is often mistaken for this kind of debris, he said.
"People find all sorts of black rocks and they get my name and they send them to me and they get very disappointed, some people get very upset even, when you tell them they are not from outer space."
Close encounter with meteor
Two Hamilton friends who had a close encounter with the meteor said they thought the bright blue flashes were "the end".
Read more: Meteor near miss for Hamilton friends
Fletcher Hodge, 33, and Michael Mckee, 30, were travelling back from Rotorua having purchased a possum plucker off TradeMe when they noticed the sky getting "bluer and brighter".
Mr Hodge, 33, said he looked out the driver's side of the vehicle they were travelling in to view what he thought was a shooting star.
"The next minute it was practically at the right hand side... like only 200-300 metres away. It came in slow then sped up. There were big bright blue flashes and then it went straight down into a gully," said Mr Hodges.
"I was quite freaked out. I was like, what the hell... this is the end.
"I've seen shooting stars and comets break up but I have never been so close in my life. It was like looking out at a street light from your house and it looked closer than a street light."
Witness reports consistent with meteoritic material
David Britten, astronomy educator at Auckland's Stardome, said witness reports were consistent with meteoritic material or space rocks entering the atmosphere.
"It's interesting that this has been seen in multiple places, which seems to show that it's some sort of bunch of material that's entered the atmosphere."
Loud booms following a bright explosion often occurred when such material entered the atmosphere.
"It's a bit like watching fireworks in the distance. It takes quite some time for that soundwave to reach the ground. It would seem to indicate meteoritic material."
'You could actually hear the thing passing'
Auckland man Alan Charman, a keen skygazer and amateur astronomer who tracked the lights from his home in Flat Bush, also believed the explosion was a meteor. "It looked to be exactly north-east of us, heading what looked to be exactly north on the compass, streaking across the sky.
"It lit up the sky and the colours and that was almost exactly at 10pm," he said.
"I heard ... probably three or four booms of the explosion a few minutes later.
"You could actually hear the thing passing, obviously even enormously distant -- it was a sensational thing."
Mr Charman compared the spectacle to photos and videos of the huge meteor that exploded over Chelyabinsk in Russia in February 2013.
While it was nowhere near as big, last night's meteor lit up the sky in a similar way, he said.
A 'huge blinding flash'
Alex Lee, who was in Birkenhead, saw a "huge blinding flash" that turned from green to white, and a lingering smoke tail over central Auckland.
"[I've] never ever seen anything this spectacular before."
Pukekohe resident Kathryn Logan said it felt like her house had been shaken by an explosion around 10pm.
"Out the window I saw a very bright flashing light then approximately five minutes later our house was shaken by what felt like an explosion."
Aucklander Steve Bayliss, who had been out running, described a "low rumble" after seeing a flash of bright lights.
"At 9.58, there was a bright flash and just to the east of Auckland a meteor passed through the clouds. There was a long smoke trail and fire quite evident.
"It lasted for about one to two seconds. Minutes later, there was a low rumble."
In Thames, Rachel Railey said it felt like something had thumped the side of her house minutes after she saw a "very bright flash".
Karin Roussenq in Mt Maunganui described a trail of light, similar to a comet's tail, streaking across the sky.
"I was watching TV and I saw that light, which seemed to be lightning. Then I saw that golden light across the sky - like a tail of a comet - and something falling down like burning up, bright."
Dmitry Osadchiy was travelling around Coromandel for the day with his family, when he saw the flash about 10pm.
"At first we were not sure [what it was] because we were driving at night, it was so so bright... it was like headlights from the car reflecting in the mirror, but it was much more than that.
"It was a blue-ish flash across the horizon."
Mr Osadchiy said initially they thought it must of been lightning, but then they didn't hear any thunder.
"The skies were pretty clear, so it couldn't have been lightning."
Mr Osadchiy is originally from Chelyabinsk in Russia, where a huge meteor exploded in the sky in February 2013.
"I wasn't there at the time, but my parents and my brother live in that city," he said.
His family were in the country for his upcoming wedding, and quickly recognised last night's flash as a meteor.
"They guessed it was a meteor but it was kind of a joke, we weren't sure what it was 100 per cent, but it was one of the first guesses we had."
Saw what looked like a meteor in the sky above Auckland tonight. Biggest I've ever seen, with a huge red-orange sparking tail. Amazing.— Heather Battles (@anthroetc) February 11, 2015
I'm hoping that wasn't a meteor over Auckland and just Chris Hemsworth arriving from Asgard to come and be friends with me for the weekend.— Mike Kilpatrick (@mikekilpatrick) February 11, 2015
Wow! Meteor has just flashed through the sky of Auckland! Stunning!— Mark Smith (@Kiwigooner) February 11, 2015
Travelling at '144,000 kilometres an hour'
Noel Munford of the Palmerston North Astronomical Society, told Newstalk ZB this morning he was "absolutely convinced" that last night's localised event was either "bolide" (a bright meteor that explodes in the atmosphere) or mother nature doing a warm up "for some sort of inter-planetary cricket match".
Mr Munford said the Earth was splattered with meteor material.
"There is tons of it, and it ranges in size from sand grained, right up to rocks.
"This thing would have been a cricket ball-sized rock that probably broke off from some impact collision between a couple of asteroids a few million years ago and it has been wandering around the solar system until it happened to put on its display for people over New Zealand last night."
Mr Munford said the meteor would have been travelling at about 144,000km/h.
"That's fine when it's going through space when there is nothing there, but as soon as it hits the upper layers of the Earth's atmosphere, it starts a pressure situation that heats the thing up really quickly and very very quickly it starts showing some of the chemical make up."
Mr Munford said you would probably see five or six events like this a year, with half of them occurring through the day time.
"What makes this more spectacular is that it happens at night. This things got brighter than the full moon."
Auckland Civil Defence's head of emergency management planning, Richard Woods, said he didn't see the meteor, but noticed the "social media storm hit".
"I thought it would be a good opportunity for us just to clarify that it wasn't lightning as we have access to MetService data."
Mr Woods said while they were not experts, the Civil Defence monitored websites and kept tabs on any threats.
"There are a number of websites, and they take data from Nasa and data from the satellites, they basically consolidate that and push out advisories as to when some of these things may actually fall down to the Earth's surface, rather than just burn up in the atmosphere."
'The question we often get is are we prepared'
Auckland Civil Defence controller Clive Manley said last night's flash has created a lot of public interest.
"I don't think people were specifically concerned it was going to land on them last night, but they were certainly very curious about why they hadn't seen anything of that brightness for a long time.
"The question we often get is are we prepared, what do we do, and what's in place."
Mr Manley said Civil Defence did not just specifically plan for one hazard, such as a meteor.
"So in the case of a meteorite, it's the same as a volcano in Auckland, we don't know when it is going to occur... so what you do is you have evacuation plans, you have warning plans, you have arrangements with resources to be able to coordinate them and direct them.
"They will work very quickly. As soon as you press go we can get resources to an area to help, so emergency services will be there and we will be coordinating them."
Mr Manley said people's preparedness for other disasters, such as a tornado or a volcano, would apply if a meteor fell from the sky.
"If you have thought through those things you are prepared for it. I think people don't need to over analyse it it's pretty simple.
"You just need to sit down with your family unit and decide what would you do if there was an emergency."
The Fire Service said it received multiple calls but there were no reports of fire. Police received 70 to 80 calls.
On its Twitter page last night, Auckland Civil Defence & Emergency Management said it had heard reports of a "large flash and sonic booms" across North Island.
"We are not experts but would suggest was a meteor (not asteroid) Did you see it?"
On Twitter it later said the "flash" in Auckland "was definitely not lightening".
- additional reporting NZME. News Service