It might sound like something from the plot of the apocalyptic science fiction blockbuster, Don’t Look Up.
But NASA warns that the odds of a ‘city-destroying’ asteroid hitting Earth have increased yet again.
According to NASA’s Center for Near Earth Object Studies (CNEOS), the odds of the asteroid 2024 YR4 colliding with our planet have crept up to 2.3 per cent.
That means there is a one in 43 chance of the space rock colliding with Earth when it makes its closest pass on December 2, 2032.
2024 YR4 was first spotted in late December by astronomers at the NASA-funded Asteroid Terrestrial-impact Last Alert System station in Chile.
Since then, it has leapt to the top of both NASA’s and the European Space Agency’s (ESA) lists of impact risks as the probability of an impact continues to increase.
Just a week ago, NASA considered the probability of the asteroid hitting Earth was only 1.3 per cent.
With an estimated diameter of up to 90 metres (300 feet) – around the same size as the Statue of Liberty – the asteroid could do some serious damage, should it hit Earth.
NASA has warned that the probability of the ‘City Killer’ asteroid 2024 YR4 hitting Earth is now 2.4 per cent, or a one in 43 per cent chance (stock image)
Although it sounds like something from the plot of Don’t Look Up (pictured), NASA now warns that the probability of the asteroid hitting Earth has been steadily increasing since it was first spotted
Although the odds of 2024 YR4 hitting Earth are slim, it is still the biggest known threat to Earth by a wide margin.
Currently, no other known large asteroids have a probability of hitting Earth higher than one per cent.
For comparison, the next riskiest object according to CNEOS’s Sentry impact monitoring system only has a one in 370 chance of colliding.
Based on the asteroid’s brightness in the sky, astronomers estimate that 2024 YR4 is between 40 and 90 metres (130 to 300 feet) across.
That would make the asteroid roughly the same size as the Tunguska asteroid which unleashed a blast equivalent to 30 megatons of TNT and flattened 830 square miles (2,150 square km) of forest in Siberia.
That has earned it a rare score of three on the Torino Impact Hazard Scale, which rates the danger of asteroids between one and ten.
The Torino scale describes this threat as: ‘A close encounter, meriting attention by astronomers. Current calculations give a 1% or greater chance of collision capable of localized destruction.’
The only object to ever receive a higher rating than this was 99942 Apophis, nicknamed the ‘doomsday asteroid’, which was given a rating of four on the Torino scale.
2024 YR4 was first spotted in late December last year and has quickly leapt to the top of NASA’s list of potential hazards. Current estimates suggest that there is a chance of the asteroid hitting Earth on December 2, 2032
Asteroid 2024 YR4 is about the same size as the Tunguska asteroid, which caused the largest impact event in recorded history when it shot through Earth’s atmosphere in 1908, flattening a massive area of Siberian forest (pictured)
However, after more observations confirmed that Apophis had no chance of hitting Earth it was downgraded to a zero.
Astronomers now hope that 2024 YR4 will follow a similar progression as more observations reveal its exact trajectory.
Dr Shyam Balaji, of King’s College London, told MailOnline: ‘As additional observational data is gathered, the probability of impact is expected to decrease.
‘NASA and ESA astronomers are actively refining 2024 YR4’s trajectory, and historical trends show that most objects initially flagged as risks eventually become non-threats.’
As asteroid detection technology has improved scientists are likely to detect more asteroids with a slim chance of collision that would have previously been ignored.
This means that, in all likelihood, 2024 YR4 will end up missing Earth by a safe margin.
However, the problem is that the asteroid is already more than 27 million miles (43 million km) from Earth and is moving away at over 29,000 miles per hour (46,800 kmph).
That means the window to observe 2024 YR4 is rapidly closing.
Analysis of 2024 YR4’s orbit indicates that the asteroid will make a very close pass of Earth in 2032. However, the asteroid is currently moving out of view and, after April, won’t be visible again until 2028
‘The asteroid will become too faint to observe from Earth after April 2025 and won’t be visible again until 2028, making it difficult to further refine its trajectory in the short term,’ says Dr Balaji.
That means it is critical for astronomers to gather as many observations now as possible to get as close as possible to the true probability of an impact.
The ESA says that it will be coordinating with increasingly powerful telescopes to gather more data, culminating in observations from the European Southern Observatory’s Very Large Telescope in Chile.
This is vital because, when the asteroid next comes back into view, Earth will only have four years to decide whether steps need to be taken to deflect it.
If the decision is made to push the asteroid off its current course, the most likely option would be using a ‘kinetic impactor’ to push it aside by ramming a satellite into the asteroid as fast as possible.
In 2022, NASA’s DART mission showed that it was possible to significantly alter the trajectory of a large asteroid with a satellite collision.
However, kinetic impactors will take time to move a large asteroid to a safer course, so Dr Balaji says that nuclear deflection ‘could be a last resort if time is limited’.
