NASA astronomers say there's a small chance a distant asteroid could hit Earth three days before Christmas in 2032 - but much remains unclear. Our science and tech team were joined by an Oxford astrophysicist and a planetary scientist to answer all your questions today - catch up below.
Wednesday 19 February 2025 16:32, UK
We've now finished our Q&A, during which we heard insight from Oxford astrophysicist Professor Stephen Smartt and planetary scientist Terik Daly.
If you want to catch up, you can scroll down or watch the video above.
Is this good practice if we ever get a more dangerous asteroid?
The most likely result here is the probability of collision drops to 0%, Terik Daly says.
But this would still be a good lesson, says Daly, in terms of our readiness, how the communications around this were carried out and how people responded.
It's one thing to consider this in a hypothetical situation, he adds, but another thing entirely when it's for real.
So this is a "critical" learning opportunity, he says, if nothing else.
Will the asteroid have to be knocked off course? How are we able to do that?
Discussions about a potential space mission won't begin until the object is no longer observable by telescopes, planetary scientist Terik Daly says.
He was part of the DART mission that knocked the moonlet Diamorphus off its orbit by smashing a satellite into it.
"As long as it's observable, there's always the possibility that new observations could drop the impact probability to zero," he explains.
Daly said it is important when trying to deflect an asteroid to do so early.
"Think about tapping your brakes before a car crash," he says.
"If you tap them early, you can do so lightly. Whereas if you wait until you're close to that collision, you have to hit the brakes a lot harder.
"If this object is on a collision course we want to try to prevent its impact early because that gives us more time for the change in the asteroid's orbit."
Will we have enough time to act if we need to?
After April, we won't be able to see the asteroid until 2028.
Terik Daly says it would be challenging to only start thinking of solutions - if they are needed - in 2028.
So, it will be interesting to see what exactly space organisations do after the spring, he says.
But as he said a couple of posts below, there are teams all over the world constantly practicing how to respond in certain situations.
Where could the asteroid land? Are there places where it would be better or worse for it to land?
The places at the biggest risk of being hit by the asteroid will be determined by its orbit, planetary scientist Terik Daly says.
He explains it would be better for the asteroid to land in the middle of the ocean far away from land, as opposed to landing on a major metropolitan area.
"The uncertainties in the asteroid's orbit are large enough that 97% of the potential paths through space do not have the asteroid hitting the earth," he adds.
What if the asteroid hit the ocean?
If the asteroid hit a metropolitan area, then it could cause problems, says Terik Daly.
But international organisations have practiced how to respond to this kind of situation, if the worst happens.
"They are paying attention," he adds, saying NASA has a team dedicated to looking into different kinds and locations of impact.
This should be reassuring, he says.
Would the asteroid destroy Earth?
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Terik Daly says current estimates put it between 40-90m (130ft to 300ft) wide, meaning it can cause a variety of impacts.
People often think of the dinosaurs when they hear the word asteroid, but Daly points out that meteor was the size of Mount Everest.
That's nothing like the scale of rock we're dealing with here.
The interesting thing to look for is its composition, says Professor Stephen Smartt.
If it's rocky, it may burn up and explode in the atmosphere, though that can still cause devastation, he explains.
People may need to be evacuated in the (unlikely) event this asteroid collides with the planet, he adds.
What are the uncertainties over how big the asteroid is?
One of the key uncertainties we have in how big this asteroid is, planetary scientist Terik Daly says.
He explains that telescopes are largely looking in visible light to try to determine its size, which can make it difficult.
"If you are staring at a lump of coal in one hand and a piece of chalk in the other, the brightness that's coming back to your eye could be the same," he explains.
He says the James Webb Space Telescope observations will directly measure the size of the object by looking at the infra-red emission.
"We are actually measuring heat coming off the object and we are not as sensitive to the uncertainties in the reflectivity of the object," Daly adds.
"Understanding how big this is would have significant implications on what the consequences would be."
Will we know anything more about its trajectory before 2028?
We won't know an awful lot more by April when the asteroid disappears, says Professor Stephen Smartt.
What will help is looking through pre-archival images to understand its orbit more and try to trace its movements there.
But he doesn't think they will get much more insight on its orbit before it disappears and returns in 2028.
What are we looking for in observations?
Professor Stephen Smartt points out the asteroid is now 600 times fainter than before and smaller telescopes can no longer see it.
Larger, more complex telescopes will be keeping watch instead, looking out for specific measurements and to help calculate its orbit more precisely, he explains.
There are only a few weeks of observations left, Smartt adds, with the asteroid about to disappear until 2028.
