NASA gives update on the odds of 'city killing' asteroid impact in 2032

Following fluctuating odds over the past month or so, NASA has once again updated the risk factor of the 'city-killer' asteroid striking Earth in 2032.

The asteroid, which is called '2024 YR4,' was discovered late last year (27 December) by a telescope in Chile.

According to the European Space Agency (ESA), 2024 YR4 is estimated to be between 40 and 100 meters wide, big enough to potentially wipe out an entire city.

Eight densely populated cities - Bogotá, Abidjan, Lagos, Khartoum, Mumbai, Kolkata and Dhaka - have since been warned that they're on the space rock's possible hit list.

NASA has once again updated the odds of asteroid 2024 YR4 hitting Earth (X/@NASA)

Initially, scientists weren't all that concerned about the odds of the asteroid actually making impact with our planet.

In a press release published on 31 January, NASA confirmed that the asteroid 'has a more than 1% chance of impacting Earth on Dec. 22, 2032 - which also means there is almost a 99% chance this asteroid will not impact'.

Meanwhile, Catalina Sky Survey engineer and asteroid hunter, David Rankin, told Space.com that 'people should absolutely not worry about this yet', adding: "Impact probability is still very low, and the most likely outcome will be a close approaching rock that misses us."

However, the odds of impact have since changed so many times it's hard to keep track.

The space boffins first said there was a 1.2 percent chance of it striking us, which climbed to 2.3 percent, then 2.6 percent.

And, on 18 February, it once again rose to a pretty scary 3.1 percent or 1 in 32 chance, making it the highest risk level of any large asteroid since records began.

As of yesterday, NASA reports a 0.28 percent chance of impact (Catalina Sky Survey/ LPL/Dr. Wierzchos/ Bryce Bolin/Twitter/@estelsiplanetes)

At the time, Bruce Betts, Chief Scientist at Planetary Society, said: "Naturally, when you see the percentages go up, it doesn't make you feel warm and fuzzy and good."

However, he explained that as astronomers collect more data, the probability of impact will likely continue to rise before quickly dropping again.

And that's exactly what's happened.

Following a further 24 hours of observation and data collection, as of yesterday (20 February), the impact probability has plummeted back down to a tiny 0.28 percent or roughly one in 357, according to NASA, so we can all breathe a collective sigh on relief.

NASA says that the prediction of 2024 YR4's path 'improves with every observation' and they will continue to observe the asteroid until April, after which it will become too faint to detect from Earth until June 2028.