Meteorites hit New 茄子视频app官网three or four times a year, but the fireball that shot across the sky above Cook Strait last week was unusual.
It had the explosive power of 1,800 tonnes of TNT and was captured from space by US satellites. It set off a sonic boom heard throughout the southern parts of the North Island.
Witnesses described a 鈥済iant bright orange fireball鈥 and a flash that left a 鈥渢rail of smoke that hung around for a few minutes鈥.
The fireball was most likely caused by a small meteor, up to a few metres in diameter, traversing Earth鈥檚 atmosphere. It was one of only five impacts of greater than a thousand tonnes of energy globally in the past year. Most meteors are tiny, creating 鈥渟hooting stars鈥 that only briefly skim the atmosphere.
The fragmentation of the meteor produced a shock wave strong enough to be picked up by听, a network of earthquake seismometers, with a flash bright enough to be recorded by a global lightning-tracking satellite. The Metservice鈥檚 Wellington radar picked up the leftover smoke trail south of the tip of the North Island.
But what is the chance of finding any of the its fragments, or meteorites, that dropped to Earth?
As part of听, a recently established collaboration between the universities of Otago and Canterbury and the astronomy community to track down freshly fallen meteorites, we are deploying specialised night-sky meteor cameras across New Zealand.
Fireballs Aotearoa鈥檚 meteor cameras only operate at night, but the compiled witness reports reveal the July 7 fireball travelled from northwest to southeast and most likely fragmented over the ocean. Unfortunately, any meteorites are therefore probably inaccessible.
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Meteorites on Earth
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Earth mainly gets meteorites from the asteroid belt, the Moon and Mars. They range from those only visible with a microscope to gigantic ones, such as the roughly 10km-wide meteorite that triggered the extinction of dinosaurs 65 million years ago.
Meteorites are scientific goldmines. Some contain material from before the Sun formed. Others tell us about the history of the young Sun鈥檚 planet-forming disk, when dust circulating around it began to clump into larger rocks and, eventually, planets.
Lunar meteorites show the Moon originated from the collision of a small planet with Earth. Martian meteorites tell us about the surface and interior of our closest planet. We don鈥檛 even need to send a spaceship.
If a meteor is recorded by several night-sky cameras, then its trajectory can be calculated and any resulting meteorites potentially located. The trajectory also tells us the meteor鈥檚 pre-impact orbit, allowing us to estimate where in the Solar System it originated.
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How to help find a meteorite
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New 茄子视频app官网has nine known meteorites. Although the fireball wasn鈥檛 seen, the most recent was the听听that crashed through an Ellerslie roof in 2003. Our听听shows this rock belongs to the ordinary chondrite group and therefore was part of a small asteroid only slightly younger than the Sun.
Last year, the British citizen-led听听captured footage of an enormous fireball over southern England. The听听in Winchcombe, Gloucestershire 鈥 where the owner initially assumed someone had emptied their barbecue.
Now on display in the Natural History Museum in London, the Winchcombe meteorite turned out to be a type incredibly听.
It is similar to the 5g of material returned in 2020 from听, except the meteorite gave scientists a hundred times as much to work with.
Although the Wellington fireball on July 7 probably didn鈥檛 drop a meteorite on land, the next one might. And you can join the meteorite hunt by reporting any sightings to听.
This article was originally published on听.
