It might sound like a scene right out of the latest science-fiction blockbuster.
But scientists now say that there is a very real chance Earth will be hit by a ‘city killer’ asteroid on December 2, 2032.
With an estimated diameter of up to 300 feet (90 metres), the asteroid, called 2024 YR4, is around the same size as the Statue of Liberty.
Now, using calculations designed for nuclear weapons, this terrifying graphic shows exactly how much damage it would cause if it hit our planet.
Dr Shyam Balaji, of King’s College London, told MailOnline: ‘If 2024 YR4 were to impact Earth, it could release energy roughly equivalent to several megatons of TNT.’
Based on the Tunguska asteroid which flattened 830 square miles (2,150 square km)of Siberian forest in 1908, conservative estimates put the 2024 YR4 asteroid’s destructive power at 15 megatons of TNT.
If that were detonated above central London, the blast would be powerful enough to shatter windows and cause injuries in Slough 24.6 miles (39.6km) away.
So, would your neighbourhood survive the blast?
What is 2024 YR4?
The asteroid 2024 YR4 is a so-called ‘city killer’ asteroid which has been determined to have a low chance of impacting Earth on December 2, 2032.
The asteroid was first spotted in late December last year by astronomers at the NASA-funded Asteroid Terrestrial-impact Last Alert System station in Chile.
Since then, this deadly space rock has become a growing matter of concern as the probability of an impact continues to rise.
When it was first spotted, NASA assigned the asteroid an impact probability of just 1.2 per cent, meaning there was an almost 99 per cent chance that it would pass by safely.
However, that probability has now been increased to 2.3 per cent, or a one in 43 chance that the asteroid will strike Earth.
This is currently the only large asteroid with an impact probability higher than 1 per cent, making it by far the biggest risk to Earth in space.
That has warranted assigning 2024 YR4 a score of three on the Torino Impact Hazard Scale, which rates the danger of asteroids between one and ten.
Scientists currently predict that the 90-metre-wide (300 feet) asteroid 2024 YR4 has a one in 43 chance of hitting Earth in 2032. If it does it would cause widespread damage to a populated area
The only asteroid to ever receive a higher rating was the 375-meter-wide (1,230ft) 99942 Apophis which was later downgraded to a rating of zero back in 2006.
How much damage would the asteroid cause?
Based on the size, density, and speed on the incoming asteroid, it is possible to work out how much energy it would release upon impact.
Additionally, thanks to past impacts like 2013 Chelyabinsk meteor which exploded over Russia, we know that 2024 YR4 would likely explode at a relatively high altitude in what is called an ‘airburst’.
Dr Balji says: ‘The blast would be comparable to a large nuclear explosion, potentially resulting in widespread damage and casualties if it hit a major city.’
While the exact force will be determined by the angle it passes through the atmosphere, a reliable estimate puts the explosive force at around 15 megatons of TNT.
For comparison, that is 100 times more powerful than the bomb dropped on Hiroshima at the end of World War II which killed between 100,000 and 180,000 people.
Using a formula developed by Dr Jean Bele, a nuclear scientist from MIT, it is possible to calculate the size of the devastation produced by an airburst explosion on this scale.
Scientists suggests that, as a conservative estimate, the asteroid 2024 YR4 would explode with a force equivalent to 15 megatons of TNT. That is 100 times the force of the atomic bomb used on Hiroshima during WWII (file photo)
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 830 square miles (2,150 square km) of forest (pictured)
Within a 3.5-mile (5.7km) radius of the epicentre, peak pressures would exceed 20 lbs per square inch, toppling even strong concrete buildings and killing anyone in the area.
Out as far as 5.5 miles (8.8km) reinforced concrete buildings would be damaged or destroyed and almost everyone would be killed.
Fatalities will still be likely out to 12 miles (18.9km) in any direction from the epicentre with residential structures collapsing even at the edge of this range.
Finally, the blast would be so powerful that it would shatter windows and cause light injuries up to 24.6 miles (39.6km) away.
On MailOnline’s interactive graphic, you can see how this would apply to 10 of the UK’s biggest cities.
If 2024 YR4 fell on the centre of London, the majority of buildings out to Croydon would be flattened, potentially causing millions of casualties.
Likewise, if the blast were to fall on Cardiff it would break windows and cause injuries in Minehead, on the other side of the Bristol Channel.
Meanwhile, Manchester, Belfast, and Edinburgh would be all but wiped off the map by the size of the shockwave.
MailOnline calculates that, were the asteroid to hit central London, the blast would be strong enough to topple houses in Croydon. In this diagram, the pink area shows regions where even strong concrete buildings would be demolished, the orange shows where reinforced buildings would be damaged, the blue where residential buildings would be destroyed, and the yellow ring the range in which windows would be broken
However, these estimates are at the lower end of what scientists think 2024 YR4 could be capable of.
Some estimates suggest that the similarly sized Tunguska asteroid may have released the energy equivalent of 30 megatons of TNT.
If 2024 YR4 really does produce the same kind of blast as this earlier impact, the area of destruction could be more than twice as large.
A blast that size would topple residential buildings in a 15-mile (23.7 km) radius of the impact site.
That would cause damage in an area covering more than 3,000 square miles (7,800 square km).
And some suggest that 2024 YR4 could prove to be even more powerful than that.
Dr Edward Bloomer, senior astronomy manager at the Royal Observatory Greenwich, told MailOnline: ‘In theory, the impact could be in the order of magnitude of gigatons [a billion tons] of TNT.
‘But, lots of factors could bring this down significantly, so there are various estimates being suggested.’
If the asteroid hit Cardiff, the shockwave would break windows and cause injures in Minehead, across the Bristol Channel 24.6 miles (39.6km) away
At that scale, he says the blast would be capable of destroying everything within ‘tens of kilometres’ of the impact point and leaving a crater several kilometres across.
Should you be concerned?
Thankfully, experts say that the odds of 2024 YR4 hitting a major UK city are vanishingly slim.
Although the odds of 2024 YR4 colliding with Earth have increased, this is a perfectly normal part of astronomers refining their calculations.
As more and more observations are gathered, the probability will trend upwards before sharply dropping towards zero once scientists can calculate the asteroid’s exact orbit.
NASA and the European Space Agency (ESA) are actively tracking the asteroid’s path and most experts think it will eventually turn out to be a non-risk.
Even in the very unlikely case that 2024 YR4 does impact Earth, the chances of it hitting an inhabited part of Earth are slim.
Dr Balaji adds that the effects would be regional, not global, so ‘there would be no mass extinction event’.
Although the probability of 2024 YR4’s orbit (pictured in white) bringing it into a collision with Earth is increasing, scientists expect the probability to drop towards zero in the future
The current best estimate for the asteroid’s path places is roughly over the equator on the red line shown here. However, the odds of the asteroid landing in a populated area is extremely low even if it did hit Earth
Likely, it would need to directly impact a populated area to cause anyone any harm.
Human populations tend to be geographically clustered in a few small areas of the planet, with some estimates suggesting that 50 per cent of the world’s population lives on just 1 per cent of the land.
Even extending that to areas that humans have influenced in some way, the World Economic Forum estimates that this would be no more than 14.6 per cent of land on Earth.
Combined with the consideration that approximately 71 per cent of the world’s surface is covered by water, the odds of an 300-foot-wide (90 metre-wide) rock falling exactly on a city are extremely slim.
However, as these blast radius calculations show, 2024 YR4 might only need to land near a city to cause massive devastation.
