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The bright green meteor that blazed a trail over the skies of southern WA earlier this month served as a spectacular reminder of just how vulnerable the Earth is to threats from space.
Country police officer and amateur meteorite hunter Marcus Scott found a tennis ball sized piece of the space rock, dubbed the Mother's Day meteorite, in a salt lake about 460 kilometres east of Perth.
Mr Scott said the space rock was about the size of a tennis ball. (Supplied: Marcus Scott)
Hollywood has taught us to fear giant 'planet killer' asteroids, but it's the smaller space rocks that could destroy an entire city.
Thankfully, a NASA scientist is on the case, with the job of protecting the planet against such threats.
Dr Kelly Fast oversees NASA's Planetary Defense Coordination Office, which is responsible for identifying and tracking asteroids, and figuring out if any of these rocky bodies could be on a collision course with Earth.
Dr Fast at the Mauna Kea observatories in Hawaii. (Supplied)
Small asteroids pack a punch
Larger meteors can survive the trip through the atmosphere, often in spectacular fashion, like the Mother's Day meteorite which was estimated to be about half a metre in size.
It slammed into the atmosphere above WA travelling at about 15 kilometres a second, before breaking up and landing in a salt lake in the Goldfields.
The meteorite was located on a salt lake south of the Breakaways. (Supplied: Marcus Scott)
Dr Fast and her colleagues around the world track more than 37,000 near-Earth asteroids, with the US Congress expecting NASA to find 90 per cent of asteroids larger than 140 metres.
she said.
It's the smaller asteroids that pose the danger because they are harder to find, but could still destroy a land mass the size of an Australian city or even a state.
"The asteroid hazard is a global issue. The first order of business is finding asteroids… it's the only natural disaster that you could potentially prevent," she said.
Dr Fast says smaller asteroids pose a danger because they are harder to find. (ABC News )
Last year an asteroid named 2024 YR4 was discovered, with initial calculations indicating it could come dangerously close to Earth in just seven years' time.
With a diameter of approximately 50 metres, if it struck the earth it could cause widespread devastation of a similar scale to the Tunguska event in Siberia in 1908.
That explosion occurred over a sparsely populated area, flattening more than 2,000 square kilometres of forest.
Gift for future generations
Dr Fast said there were a few different forms of technology that could potentially be used to neutralise the threat from an asteroid, and they all sound like they are straight out of a science fiction movie.
The Double Asteroid Redirection Test (DART) spacecraft slammed into the asteroid Dimorphous in September 2022, successfully changing the orbit of the 160-metre diameter celestial body.
"That was the simplest technique — to impact an asteroid and change its speed, and it was successfully tested with DART," Dr Fast said.
NASA's DART mission was the first test of a planetary defence system designed to prevent a potential meteorite collision with Earth. (Supplied: NASA/Johns Hopkins APL)
To date, it's been the only real world test to save the planet from destruction caused by a rogue space rock.
Other techniques being studied include ion beam deflection, using a spacecraft to fire charged particles at the asteroid, giving it a slight nudge to change its orbit.
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The 'Star Trek' sounding "gravity tractor" is another possible solution, and entails parking an object next to the asteroid and using the slight change in gravity to change its orbit.
"And then there's what we always like to call the Hollywood option, because it's what's always used in the movies — a nuclear deflection," Dr Fast said.
Although she warned such a technique could create even more of a hazard from the debris field of an exploded asteroid.
Dr Fast is hoping there won't be a need to use any of these techniques in our lifetime, but says developing the technology to protect the planet will be a gift for future generations.
Keeping an eye out down under
This week Dr Fast spoke at the Australian Space Awards in Sydney, where she emphasised Australia's importance in keeping the planet safe from the threat of asteroids.
And while Australia might be half a world away from NASA headquarters in Washington D.C., two teams of Australian researchers form part of the International Asteroid Warning Network.
The University of New South Wales Canberra team search for asteroids using optical telescopes as well as the Parkes Radio Telescope, famous for its role in broadcasting Neil Armstrong's moon walk.
Parkes, based in New South Wales, is one of the world's leading radio telescopes. (Supplied: CSIRO/A.Cherney)
On the other side of the country, researchers at the University of Western Australia use the one-metre diameter Zadko Telescope, located about 70 kilometres north of Perth in Gingin, to scan the skies for threats from space.
Hollywood-born Dr Fast has a degree in astrophysics and a doctorate in astronomy.
Dr Fast, pictured with her dog, had a space rock named after her. (Supplied)
She also has the honour of having a nearly three-kilometre diameter space rock named after her, Asteroid Kellyfast.
"Like pretty much all asteroids that are named for people, let's hope it stays safely out in the main belt [of space]" she said with a laugh.
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