The chance of asteroid 2024 YR4 impact plummets to 0.001%

As expected, the odds of asteroid 2024 YR4 hitting Earth in 2032 have plummeted. The European Space Agency now estimates a 0.0016% chance of collision. The US space agency NASA estimates a 0.0050% chance.

2024 YR4 has fallen on the list of maximum threats of both agencies. The rock now has a risk level of zero on the Turin scale, which measures the danger of these bodies for our planet from 0 to 10. Despite this, the largest space telescope in the world, NASA's James Webb , continues with its plans to observe and locate this body with precision at the beginning of March, Julia de León, a researcher at the Institute of Astrophysics of the Canary Islands, explains to this newspaper. The objective is to fine-tune its real size, which currently ranges between 40 and 90 meters. "It is interesting to see the capabilities of the Webb , especially in view of future events of this type," reasons the astronomer, whose team estimated that the asteroid is made of rock and metals, so it would probably have survived its entry into the Earth's atmosphere.

2024 YR4 had become the most dangerous asteroid detected since records began in 2001. The chance of impact began to rise earlier this year, from an initial 1.2% to more than 3%, putting it ahead of the previous biggest known threat, the asteroid Apophis . In 2004, the 1,000-foot-wide body peaked at a 2.7% chance of impact before rapidly dropping to 0. That’s because as ground-based telescopes make observations, the body’s trajectory gets narrower until Earth is out of its path. Much like what’s now happened to 2024 YR4.

The disturbing visit of this body in 2032 has served to oil the international mechanisms of surveillance and reaction to space threats. In particular, the two United Nations agencies charged with studying the trajectory of threatening asteroids and proposing measures to avoid an impact using space missions similar to DART , the first space probe that managed to deflect an asteroid, have been activated. This second agency, SMPAG, was scheduled to meet in May if the threat of 2024 YR4 was still present.

2024 YR4 was at risk level 3 on the Turin scale. Apophis was at risk level 4, because it had a much larger diameter, about 375 meters. Given its size, 2024 YR4 did not pose an existential threat to humanity, but it could destroy a city if it were to fall on a populated area.

Much of its impact depended on factors still unknown, such as its composition and the angle of entry into the Earth's atmosphere. This body could cause an impact similar to that of the Barringer crater in the United States, which wiped out all forms of life within a radius of four kilometers. It could also disintegrate in the air, which could cause a disaster comparable to the Tunguska bolide (Russia), which in 1908 devastated vegetation over an area similar to the island of Gran Canaria. A few days ago, scientists from the Institute of Astrophysics of the Canary Islands estimated that the composition of 2024 YR4 is rocky with a high metal content. This means that it would probably have survived its entry into the atmosphere and would have left a crater if it had fallen on Earth .

Every day for the past few weeks, planetary protection services in Europe and the United States have been analysing a growing number of observations of this body from ground-based telescopes – more than 440 according to the latest data. They used this material to project the body's actual trajectory on a daily basis, with a margin of uncertainty. At first, Earth was almost in the centre of the corridor that this body, whose diameter is between 40 and 90 metres, could pass through. As the width of this corridor narrowed, our planet occupied a larger portion, which explains why the chances of impact increased for days. Finally, Earth was left outside this possible trajectory.

2024 YR4 passes close to our planet every four years, but the last critical one was in 2032, scheduled for December 22. According to current forecasts, there is still a greater chance of the asteroid hitting Earth (one in 20,000) than of winning the Christmas lottery (one in 100,000).