TRANSCRIPT
It’s a premise out of many a science fiction film.
An asteroid is hurtling towards Earth and humankind must band together to avert catastrophe.
Movie clip: "The bible calls this day armageddon: the end of all things. And yet, for the first time in the history of the planet, a species has the technology to prevent its own extinction."
But did you know that this sci-fi scenario has a very small chance of becoming a reality?
For the first time ever, the United Nations has activated its Planetary Security Protocol due to a small chance of an asteroid collision in 2032.
"It feels like science fiction, but this is science fiction in real life. Asteroid impacts are a genuine concern. We know that they can have quite destructive effect. Famously, we think that an asteroid may have wiped out the dinosaurs, for example. Recently, there was one in Russia that many people caught on dash cams a few years ago. So the one that we're talking about now is much bigger than that one."
That's Tamara Davis, a Professor of Astrophysics at the University of Queensland.
The asteroid in question, called Asteroid 2024 Y-R-4, was first recognised as a threat in December 2024 by the Asteroid Terrestrial-impact Last Alert System [[ATLAS]] telescope in Chile.
Since then, Luis Cano of the Planetary Defence Office says his team at the European Space Agency have been monitoring the object closely.
“After discovery, as we typically do, we start collecting more measurements, more observations and we quickly saw that the object was, let's say, having impact chances with the Earth in December 2032.”
Currently NASA says there's a 2.2 per cent chance of the asteroid hitting earth.
So, what happens if it does? Could this mean the end of the world?
Well, not quite.
But Professor Davis says it would be no insignificant impact either.
"So it's a serious-sized object. We are talking 40 to 90 meters, those are the estimates that have come out and that's really sizable for an asteroid. And if it was to hit, it would have the potential to wipe out something the size of a city, it could do significant damage. I saw an estimate that the destructive potential would be significantly more than a nuclear bomb. It would be about 500 times Hiroshima."
That being said, in the roughly one in 50 chance the asteroid does hit Earth, the professor says it's unlikely to hit a well populated area.
"The reassuring thing is that even if it does hit us, most of the earth is not city. So the likelihood that it would actually hit earth and pinpoint precise enough to hit somewhere where there's a major population center is pretty low."
So if the asteroid does hurtle in our direction what can we do to avert disaster?
Well, you may have missed it, but in September of 2022 NASA had a mission known as the Double Asteroid Redirection Test to practice deflecting an asteroid.
"And lift off of the Falcon 9 at DART on NASA's first planetary defence test to intentionally crash into an asteroid."
The mission was a big win for our planetary defence teams, with the spacecraft successfully redirecting the asteroid Dimorphos.
"This was just a practice, like a demonstration of a way that we can deflect an asteroid. Now we need to do it as early as possible. So if we notice an asteroid as it's like a hundred meters away from earth, there's no chance we can deflect it. If we notice it early enough, we can give it a tiny little nudge. Because these things are heavy and we can't launch stuff there that would really give it a really big push. But we can just give it a tiny nudge and that'll make it drift far enough away that it will avoid hitting us."
Dr Evie Kendal, from the Ethical, Legal and Social Implications of Emerging Technologies research group at Swinburne University of Technology says methods like NASA's DART system do carry risks as well though.
"If you collide with an asteroid, you're probably creating space debris. You might also redirect it into a pathway that is not ideal. So you might plan to deflect it in a particular way and you may not actually be successful for a number of reasons. So you could have actually caused a different impact problem there."
Dr Kendal says, if we don't have as much time to react, we do have a couple more options on the table but they each contain risks as well as ethical and political dilemmas.
"We've got a few other theoretical technologies like space lasers. Some people are working on that problem saying we could ablate part of the asteroid change its mass and therefore we can change its direction, et cetera. And of course, we do have the traditional nuclear explosive devices that would attempt to destroy the asteroid. Again, that's space debris problem is an ethical issue. It's also a practical issue of course, but we definitely don't want people stocking up on nuclear weapons just saying that we're going to use them to deflect asteroids or destroy asteroids. So again, very sensitive issues there."
Now, one of the more practical questions is: if there is an imminent threat of an asteroid strike who exactly is in charge of making those key decisions on planetary defence?
Dr Kendal says we don't really know.
"So everyone assumes, of course, that the UN will be involved. However, not everyone agrees that that's the group that necessarily has the mandate to engage in planetary defence. They will be coordinating different efforts, but the reality is at some point someone has to actually make the decision, do we attempt to deflect this asteroid or not? And we don't really know who that person or who that group actually is. So it's definitely the time to settle those kinds of issues in terms of policy, ethics, governance."
She says the risk of not laying out a clear plan of action now is that when an asteroid threat emerges, especially if we have limited notice, the confusion could spell destruction.
"Of course, the very worst case scenario is that we have conflicting planetary defense actions. So like a private company decides it wants to do this and then one national space agency decides it wants to do something else. And you can imagine that the motivations might be different depending on the predicted impact site. So if the predicted site of impact is your country, of course you're going to have different feelings about that than if it's on the other side of the world. So we definitely need to be on the same page to make sure we don't have conflicting responses to the same event."
So, back to the most immediate planetary threat.
Asteroid 2024 Y-R-4 is currently moving away from the Earth as it orbits the Sun and we will lose sight of it in about April.
But it is due to return in 2028.
Luis Cano from the European Space Agency says we'll know for sure in 2028 whether it will likely impact the earth or potentially even hit our moon.
"When it will come back in 2028 and we re-observe it, at that time it will have been so much time enough for us to determine whether it will be impacting or not completely. So it would be a zero or 100 per cent.”
So, we'll know more in April and much more by 2028, so don't start preparing for the end of the world quite yet.
