An asteroid heading towards Earth could wipe out a city, but what ...

12 Feb 2025

SBS

An asteroid heading towards Earth could wipe out a city but what

NASA’s keeping an eye on asteroid that could slam into the earth in 2032, but what are the chances?

Key Points

The calculated likelihood of the asteroid hitting Earth has increased since first being detected in 2024.
While it could hit Earth on 22 December 2032, it is most likely to pass by without making contact.
NASA is monitoring the asteroid but in April it will become too faint to observe again until mid 2028.

NASA has announced an asteroid that is heading this way, has a greater chance of hitting the Earth than initially thought.

The US based space administration body had initially said it had more than one per cent chance of hitting Earth in 2032.

It now says the chance is more than two per cent.

Detection of Asteroid 2024 YR4

Detected in the last week of December 2024, the minor planet has been called Asteroid 2024 YR4 and if it were to hit Earth, it would do so on 22 December 2032.

While there is more than a 97 per cent chance it will not hit the Earth, NASA has said "currently, no other known large asteroids have an impact probability above one per cent."

Earlier this month NASA put out its statement that said the chance of the asteroid hitting Earth was 2.3 per cent.

The space agency said, "As more observations of the asteroid’s orbit are obtained, its impact probability will become better known," and that it is "possible its impact probability will continue to rise".

"Ongoing observations from ground-based telescopes involved with the International Asteroid Warning Network will continue while the asteroid is still visible through April, after which it will be too faint to observe until around June 2028," NASA's statement read.

One of the highest level asteroid warnings

University of Queensland astrophysics professor Tamara Davis told SBS News this asteroid had been given "the second highest warning scale that we've ever had in our alert system for asteroids that might impact Earth".

"It feels like science fiction, but this is science fiction in real life, asteroid impacts are a genuine concern," she said.

"We know that they can have quite destructive effects," she said, pointing to the widely accepted theory that an asteroid wiped out dinosaurs.

"We've also seen some more recently, that caused breaking glass and shock waves as it came through," Davis said.

How big is Asteroid 2024 YR4?

"The one that we're talking about now is much bigger than that one and is going to pass. They expect it to pass close to Earth, maybe closer than the moon, is its current expected sort of direction and there is a slight chance that it will hit us."

Davis described Asteroid 2024 YR4 as “a serious-sized object".

"We are talking 40 to 90 meters is the estimate… and that's quite sizeable for an asteroid."

"If it was to hit [Earth], it would have the potential to wipe out something the size of a city, it could do significant damage."

She said the chances of the asteroid hitting a populated part of Earth were much lower than the 2.3 per cent chance of it hitting the planet in the first place.

"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 centre is pretty low, so that is reassuring."

However, if there is a collision, there is potential for a huge amount of damage.

Where on earth?

She said at this stage it was too early to tell if the asteroid was to hit Earth, whereabouts impact could potentially take place.

"We still are uncertain within half a day exactly when it would hit," Davis said.

She said as the asteroid moved closer, such forecasts may be able to be refined.

"Typically, they'll end up with a stripe across the earth, which is sort of the region of danger and that's the area that we could warn people if we thought something dangerous was actually going to hit."

At the same time, NASA has also pointed out that "several" other objects with a "probability of impacting Earth" had been on its asteroid risk list in the past before further observations saw them reassigned as having zero risk.

Planetary defence

It was the NASA-funded Asteroid Terrestrial-impact Last Alert System station in Chile that detected and reported Asteroid 2024 YR4.

Davis said the "first step of planetary defence is to watch”.

She said while human capability to map what is in the sky has improved dramatically in recent history, there was always a chance that an asteroid could make it close to Earth without being detected.

"We could definitely still be completely blindsided," Davis said.

Diverting asteroids

She said if an asteroid was detected early enough "we can give it a tiny little nudge… and that'll make it drift far enough away that it will avoid it hitting us".

NASA Double Asteroid Redirection Test (DART) space probe took place in 2022 to study the effect of an impact with near-Earth objects. Source: Getty / All About Space Magazine/Future Publishing

There was recently a mission called the Dart Mission that went and deflected an asteroid.

"It took a spaceship up, a satellite up, it fired something at an asteroid and tried to change its path and so this was just a practice, like a demonstration of a way that we can deflect an asteroid," Davis said.