In the first ever mission of Earth's "planetary defence", Nasa has launched a mission for a spacecraft to intentionally collide with an asteroid, and knock it off its path.
It's part of a plan to save the Earth from the potential risk of what are being described as "city-killer asteroids", and it could become the only natural disaster that can be predicted and prevented.
New Zealand scientists will be watching closely next year when the spacecraft slams into Dimorphos, the moon of the Didymos asteroid, to see how it affects its orbit.
Photo: NASA/Johns Hopkins Applied Physics Lab
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One of those astronomers is Dr Michele Bannister from the University of Canterbury, who will be observing the collision next year from Mt John Observatory.
She tells Nine to Noon it’s a hugely exciting event for the field.
“It’s going to give us the opportunity to start to prototype an understanding of how asteroids move and behave which means we can work towards that goal of making one of the natural disasters we know about eventually go away.”
Bannister says the asteroids they’re worried about are ones that are just under a kilometre across.
“The ones that might be called dinosaur killers, we have a good handle on that population. The ones smaller than that, we don’t know where all of them are yet, we’re still working on that. There are big surveys underway to try and discover them.”
She says only around 40 percent of those smaller asteroids have been found so far and the Didymos asteroid was selected because its one we can get to.
“To try and understand how you could potentially move an asteroid if one of them was found that was on hazardous path and could potentially collide with Earth, to develop that technology you first need to go to an asteroid and this is one we can get to.”
The test will involve throwing a thing about the size of a chest freezer at the Dimorphos at very high velocity to see what happens. She says that there are currently no known asteroids on a hazardous path toward Earth so we don’t need to start worrying.
“What we’re trying to do is provide the technology so that, if one were found, we have something we can do about it… in living memory, we haven’t had one hit that reached the ground in a way that could cause severe damage. But we look at the geological record and we know that this things do happen.
“This is trying to think outside the timescale of our day to day lives and putting those plans in place so we have the tools to do something about it if or when we do find one.”