NASA confirms odds of ‘city-killer’ asteroid hitting Earth have increased

NASA has revealed that the odds of an asteroid dubbed the “city killer” hitting Earth have increased – and it could happen pretty soon.

NASA has increased the odds of a ‘city killer’ asteroid hitting Earth. Credit: Science Photo Library – ANDRZEJ WOJCICKI/Getty Images

Astronomers discovered the asteroid, named YR4 2024, was hurtling towards Earth in December and have been keeping a close eye on it ever since.

They have been gathering data to work out its precise orbit and calculate the likelihood of it hitting Earth – and the odds of it colliding with our planet have been increased.

The asteroid, which is thought to be between 40 and 90 meters wide, has the potential to unleash energy equivalent to 7.7 megatonnes of TNT should it hit Earth, according to New Scientist, which would be enough to flatten a whole city.

That impact would be around 500 times the power of the atomic bomb dropped on Hiroshima, according to The Independent.

NASA has been charting the likelihood of it colliding with the Earth in 2032, which was initially at a 1-in-83 chance when it was first spotted.

Scientists have been carefully tracking its trajectory. Credit: Nasa/JPL/Wikimedia Commons

The odds have been increasing ever since, moving from 1-in-67, to 1-in-53, to 1-in-43, and now to 1-in-38 – a 2.6 percent chance.

The European Space Agency has also been monitoring it and has given a slightly smaller odds of 2.41 percent.

While those numbers might sound pretty terrifying, they don’t necessarily mean that the asteroid is more likely to hit Earth as the odds can come down again, too.

Hugh Lewis at the University of Southampton, UK, explained: “Just because it’s gone up in the last week, doesn’t mean that it’s going to continue to do that.”

However, scientists will face a different challenge as they are running out of time to forecast the asteroid’s risk, as YR4 2024 is set to fly behind the sun in April, meaning it will be out of view of most telescopes based on Earth.

This means astronomers are limited with how much they can refine their predictions until it comes back into view again in 2028.

Lewis explained: “Any observations we can make between now and when it’s out of view will obviously help us to refine the orbit and to make better predictions.

“That doesn’t necessarily mean that it will go down before April. It could continue to go up, but still ultimately miss us.”

Astronomers are also already looking at past data to uncover previously overlooked observations of the asteroid, which may help refine its trajectory.

The James Webb Space Telescope will also hopefully gather crucial information on the asteroid’s size and composition in the coming months to establish whether the asteroid could make it through Earth’s atmosphere intact and how large of an explosion it could cause if it impacts.

Lewis revealed: “That will help us determine what we need to do about it, because if it’s a stony asteroid, that’s very different from a high proportion of iron-metal asteroid.”

He revealed that a stony asteroid would potentially break up during impact but an iron-rich asteroid could cause far worse damage as “the mass makes a huge difference in terms of the energy and whether or not the atmosphere has an effect on it.”

There is a chance the odds could change again in future. Credit: MARK GARLICK/SCIENCE PHOTO LIBRARY/Getty Images

Since January, NASA has put YR4 2024 at a level three on the Torino Scale, which charts the danger of NEOs (Near Earth Objects) which measure over 65 feet in diameter and have a 1 percent or greater chance of deep impact.

According to the scale, this “city-killer” asteroid is a “close encounter, meriting attention by astronomers” and has a “1 percent or greater chance of collision capable of localized destruction.”

The Independent reports that the impact risk corridor of the asteroid stretches eastwards from the Pacific Ocean, over South America, the Atlantic Ocean, Africa, the Middle East, and into Asia, and could affect around 100 million people who live in the zone.

NASA has previously successfully tested technology designed to deflect asteroids heading for Earth, notably during the Double Asteroid Redirection Test (DART) mission in 2022, which redirected an asteroid twice the size of YR4 2024.

China is also set to undertake a similar asteroid-redirection test on a smaller asteroid in 2027.

Other space agencies are also working on contingency measures for YR4 2024, as well as preparing for any necessary intervention.