The object could have been the size of a small car, experts say
People in parts of Victoria and South Australia reported seeing large flashes of bright white light, reports Business Insider.
Data from the Centre for Near-Earth Object Studies in California shows the meteorite landing site as a blue-green dot on their map of reported fireballs, as picked up by US sensors.
The object reached a speed of 44,100kmh when it entered Earth’s stratosphere – then burned and broke, with some parts landing about 300km west-south-west of Mount Gambier in the Great Australian Bight.
Professor Phil Bland from Curtin University said “the energy deposited in our atmosphere when the thing exploded, 1.6 kilotons” was impressive.
He said: “That’s very high. It’s in the range of a small nuclear weapon. Because it exploded at an altitude of 31.5km it didn’t do any damage.”
NASA aerospace engineer Dr Steve Chesley told ABC Radio the meteorite could have been the size of a small car when it entered the atmosphere, but high pressure caused it to shatter and “small pieces the size of a fist or larger” could make their way to the surface as meteorites.
You wouldn’t want it to land on your head NASA Aerospace Engineer Dr Steve Chesley
He added: “You wouldn’t want it to land on your head. But these wouldn’t really do any damage on the ground.
“What the folk there along the coast of South Australia saw was a spectacular light show, probably a very loud sonic boom that would rattle the windows, this wasn’t big enough to break windows I expect, and then just small pebbles falling to the Earth and not at hypersonic velocities, they slow down very quickly.”
The meteor reached “peak brightness” at an altitude of 31.5km, travelling at 11.5km per second, with a calculated total impact energy of 1.6 kilotonnes over the water to our south.
The data centre computes high-precision orbits for near-earth objects such as asteroids or meteoroids to support NASA’s Planetary Defence co-ordination office.
It then predicts how close they could come to Earth and the possibility of an impact.
It says on its website: “Continually updated calculations of orbital parameters, close approaches, impact risks, discovery statistics, and mission designs to possibly human-accessible asteroids are made available on this website.”
A meteorite is a solid piece of debris from a comet, asteroid or meteoroid that originates in outer space.
When the object enters Earth’s atmosphere it heats up and radiates that energy to become a fireball, which is also known as a shooting star.
The brightest fireballs are known by astronomers as ‘bolides’, which are large enough to create an impact crater.
Most meteoroids disintegrate when they enter the Earth’s atmosphere.
Few meteorites are large enough to create large impact craters.
Large meteoroids may strike the earth with a significant fraction of their escape velocity (second cosmic velocity), leaving behind a hypervelocity impact crater.
The force of such collisions has the potential to cause widespread destruction.
The most frequent hypervelocity cratering events on the Earth are caused by iron meteoroids.
Examples of craters caused by iron meteoroids include Barringer Meteor Crater, Odessa Meteor Crater, Wabar craters, and Wolfe Creek
Source: The Sun