It was in the early hours of Monday morning when Denby Turton, a mechanical fitter at the Yandi mine in Western Australia, saw a curious light streaking through the sky.
He and three others were sitting on top of a crusher, waiting for it to start up, when his boss suddenly exclaimed, “What the heck is that?” He turned, just in time to film a flaming ball of greenish blue shoot across the night.
“It went for ages, super slow,” recalls Turton, “We all couldn’t believe our eyes. I tried to video it, but all the lights on site made my camera not focus properly.”
Luckily enough, they weren’t the only people working a night shift in Western Australia. Mitch Brune, a rope access technician at Nelson Point in Port Headland, had his phone on hand. In 17 seconds, he managed to snag one of the best videos out there.
“[I]t must’ve been going for at least 30 seconds,” he wrote when contacted by ScienceAlert. “I was amazed at what I was seeing and how it lit up the sky in such a bright green glow; never in my life have I seen anything like it! Which you can tell from all the swear words in my video.”
Earlier on his night shift, Mitch had also spotted a shooting star. “I made a couple extra wishes after witnessing such a crazy visual in the sky,” he added.
An hour south along the coast, a regional police station counted their blessings by the blue light as well. ”When you come across a meteor whilst on burglary patrols,” the station tweeted.
— Karratha Police (@KarrathaPol) June 14, 2020
Unfortunately, there’s no way to tell for sure what this fireball actually was. We asked Eleanor Sansom, the project manager of the Desert Fireball Network - a system of 50 cameras, covering about three million square kilometres of sky from Western Australia all the way through to South Australia.
All night every night, this network is watching for bright shooting stars and meteoroids entering our atmosphere, so scientists can recover them if they survive the plummet to Earth.
By capturing these objects from different locations entering our atmosphere, Sansom and her team can triangulate where the fireball comes through our atmosphere.
“And with that, which is pretty awesome,” she told ScienceAlert, “you can back-calculate and figure out where it came from in the Solar System. Not only that, you can see if there’s any rock left at the end. You can figure out where it might have actually landed and go and recover it.”
That’s really valuable information given scientists have approximately 60,000 meteorites on hand, and less than 40 with enough precise data to calculate an orbit. In 2017, the network actually caught a meteorite grazing the atmosphere above Australia before being kicked out once again into space.
This most recent fireball, however, fell outside the network’s range, which means: ¯_(ツ)_/¯
At one point, Sansom says they actually had cameras in that region. But because the native rock there is magnetite (hence all the mining), it’s hard to tell this type of black magnetic rock apart from space rocks.
“We started putting cameras up there and realised it’s hopeless; that we’d never find one,” she told ScienceAlert.
Without proper data, astronomers aren’t actually sure if this incredible sighting was a meteorite burning up in our atmosphere, although there’s reason to suspect it might be.
While some have speculated it was a piece of space junk hurtling through our atmosphere, according to the Australian Broadcasting Corporation (ABC) that scenario is less likely. Astronomer Renae Sayers of Curtin University told the ABC that judging by the videos, this fireball was most likely a natural object.
When space junk enters Earth’s atmosphere, it tends to trail sparkling debris, as hunks of metal get thrown around and set on fire, she explains; meteorites, which are more dense, appear to glide right through, similar to the recent fireball.
In fact, both Sansom and Sayers agree this particular fireball looks a lot like the one that popped in and out of our atmosphere a year ago, which means it might not have even made its way to Earth.
Matt Woods from the Perth Observatory told The West Australian that the greenish blue colour was probably occurring due to burnt magnesium, whereas Glen Nagle from the CSIRO-NASA tracking station in Canberra told the ABC he thought the colour suggested a high level of iron.
Sansom says it’s hard to tell from just video. More than 95 percent of the light we are seeing is actually the atmosphere burning itself, so it’s hard to get any clues on the composition of the space rock. The only thing the colour can really tell us, she says, is how high up it’s flying.
“A lot of our fireballs will turn green and then kind of turn more orangey as they get deeper,” she told ScienceAlert.
Meteor over Cape Lambert, Pilbara region, WA last night! https://t.co/kG9srYqUEg
— Damian Hicks (@DamianHicksAus) June 15, 2020
From her experience, the object was probably the size of a basketball to a washing machine. Its fate, Sansom explains, could have gone three ways: the object might have burned up completely in the atmosphere; it could have jumped back out into space; or it could have fallen to Earth.
If it was a piece of space junk, it’s unlikely to have survived the journey. Most human-made material that gets shot into orbit is designed to burn up in our atmosphere.
Fireballs, on the other hand, usually stop burning at about 30 kilometres up (18 miles), so even if the light fizzles out, some material could still make it down.
“I would be very surprised if there wasn’t a meteorite dropping,” Sansom told ScienceAlert, although she notes it may have had enough speed to jump back out into space again.
“If anyone’s wandering around there and manages to find something then we’d be very, very excited.”
Currently, there are no plans to go looking for fallout. Scientists simply don’t have a small-enough search zone to make it worthwhile amongst all that black magnetic rock. But we can dream.