A recently formed citizen science project to track down freshly fallen meteorites is deploying specialised night-sky meteor cameras across the motu.
Fireballs Aotearoa is a collaboration between the universities of Otago and Canterbury and the astronomy community searching for freshly fallen meteorites following fireball events.
The photo was taken looking directly south in the Hutt Valley. An eyewitness says there was a huge flash of light as the meteor combusted and disintegrated. Photo: Supplied
Two weeks ago, a meteor lit up the sky during the day near Wellington and Fireballs Aotearoa members swiftly got to work trying to pinpoint where it fell.
Otago University associate professor of geology James Scott tells Nine to Noon a computer algorithm used witness reports and dashcam footage to calculate its direction and trajectory.
“It looks as though it came in from the northwest, shot across the lower North Island and then exploded just above Cook Strait.”
Meteors are trickier to track by cameras during the day, Scott says, which is why they also rely on reports and other people’s footage too.
“I would say that this particular one was quite poorly located and that’s because most of the witness reports saw the fireball from behind.
“If we got views say from 360 degrees, it would’ve been much more precisely located.”
It’s just as common for meteors to go over during the day as they do at night, but what was unusual was that it was so visible considering the sunlight, he says.
“The MetService’s radar picked up the smoke trail from the explosion, also some global lightning trackers.
“Some US space-based sensors which track explosions in the atmosphere recorded that this one exploded with about the equivalent of 1800 tonnes of TNT and that’s really large, that made it about one of the I think top five explosions in the atmosphere in the last year.”
On Thursday night, another meteor was seen over Canterbury and Scott is encouraging any witnesses to upload their report to the Fireballs website.
“This one looks like it exploded over land and that means there’s potential that we could go out and find some meteorites.”
Fourteen meteor cameras are capturing and uploading data from across the country, but Fireballs want their coverage to grow with the help of citizen scientists.
“They [the cameras] only cover about 19 degrees of the night sky so the more cameras we have, the more accuracy we’ll have,” Scott says.
“The goal is that ultimately, when a big one comes … that breaks up over New Zealand, we’ll have enough images to triangulate the area where the meteorites will have dropped.”
As seen from Moana, looking across Lake Brunner pic.twitter.com/ajT3YMwaqv
— JP (@kiwijezza) July 21, 2022
Only nine meteorite fragments have been picked up in New Zealand in the past 150 years, he says.
“The reality is we should be getting something like three to four per year.
“If we can track where the fireball was and the fragmentation, the boom, happened, then we’ll have an idea of where to search for those meteorites.”
Having these rocks will helps us gain greater understanding of our Solar System, he says, because they often come from the Asteroid belt, Mars or the Moon.
And being hot on the heels of it is important too, he says.
“People will know about iron meteorites and iron rusts pretty rapidly so if a meteor sits on the ground for along period of time, it’ll rust away basically.
“If [a Martian meteorite is] not picked up quite rapidly then the outer shell, the fusion crust that forms when the meteor comes through the sky and burns up … it loses that crust and then it’ll be virtually indistinguishable from any other rock on the ground.”
