There is an estimated 2.3% chance that the 2024 YR4 asteroid is heading our way. Here’s everything you need to know about the space rock – including how much damage it could actually cause.
Could a huge asteroid hit Earth?This is not a drill. There is a chance – albeit a small one – that an asteroid could hit planet Earth within the next decade.
The 2024 YR4 asteroid set off automated asteroid warning systems after it was spotted through advanced telescopes in Rio Hurtado, Chile, last December.
Since then, the asteroid has jumped to the top of the risk list – a catalogue of all space objects which could possibly clash with our planet.
It’s far from panic stations – but experts say the probability of an impact with Earth has almost doubled from 1.2% in January to about 2.3% now.
But how much do we know about the asteroid, and when will we know for sure if we’re safe? Plus: what could happen if it really is heading our way?
When could it hit – and where?
If there is impact, it’s estimated to be at 2.02pm on 22 December 2032 – though the precise time is prone to change, as is the exact probability of its collision with Earth.
NASA says the asteroid would likely hit somewhere across the eastern Pacific Ocean, northern South America, the Atlantic Ocean, Africa, the Arabian Sea, or South Asia.
What we know about the asteroid
2024 YR4 is estimated to be between 40m to 90m wide – or 130ft to 300ft.
It’s made of a rocky substance rather than more robust materials like iron, which is significant because it means it could break into smaller pieces if it enters Earth’s atmosphere, says Doctor Luca Conversi, who is the manager of the European Space Agency’s (ESA) Near-Earth Object Coordination Centre (NEOCC), which is heavily involved in monitoring 2024 YR4.
The asteroid is currently at level three on the Torino Impact Hazard Scale, which is a system used to determine how big a threat an asteroid or comet is to planet Earth.
Level 3 is defined as a “close encounter meriting attention by astronomers”, because it has a 1% or greater chance of collision capable of localised destruction.
The Torino Scale is the reason we know about the asteroid, because level 3 determines that the public and public officials should be notified when the encounter is less than a decade away.
For context: level 0 is when there is no chance or almost no chance of collision, and level 10 is reserved for when a collision capable of causing global catastrophe is certain.
Size matters – here’s why
There is a big difference between an asteroid that’s 40m wide or 90m wide – but experts aren’t yet sure how big this one is.
Determining its rough size was important, because it is the size which reveals how big a threat we might be facing.
Earth is bombarded with more than 100 tons of dust and sand-sized particles every day, according to NASA – but they are small enough that they typically burn up in the atmosphere before they can cause any damage.
This means an asteroid or comet can have a 100% chance of reaching Earth but still be a 0 on the Torino Scale because its size doesn’t pose a threat.
But 2024 YR4 is a level 3 threat because it is definitely larger than the 20m (65ft) threshold.
Its rough size has been estimated through the use of powerful telescopes, which are being used mainly to determine its orbit and whether it could be on course for Earth.
But those telescopes only allow astronomers to study the asteroid via the visible light it reflects from the sun.
The general rule is that the brighter an asteroid is, the larger it is, but it all depends on how reflective the asteroid is. 2024 YR4 could be 40m across and very reflective, or 90m across and not very reflective, the ESA says.
Without knowing its exact size, experts can’t determine how significant the impact could be.
That’s where NASA’s powerful James Webb Space Telescope comes in.
The device, which has previously been used to capture unprecedented pictures of stars being born and dying, is now studying the asteroid using infrared light – or heat – which will lead to a better estimate of its size.
