- February 5, 2025 - Planétarium : Astronomical News
Have you heard of the asteroid 2024 YR4? This “little” celestial voyager is now under close scrutiny by astronomers around the world. Discovered on December 27, 2024, by the ATLAS telescope in Rio Hurtado, Chile, the asteroid, between 40 and 100 meters in diameter, presents a nonzero probability of impacting Earth on December 22, 2032!
Impact probability: a threat that needs to be put into perspective
Rest assured, the probability remains slight: 1.2%, or once chance in 83. And it’s highly likely that it will drop to zero when the asteroid’s trajectory becomes better known. This is something that happens often with “potentially dangerous” asteroids that have just been discovered; we have to get to know them over a period of weeks before they deign to give us a better picture of where they’re planning to travel.
An asteroid in astronomers’ sights
At the end of January 2025, the asteroid reached level 3 (out of 10) on the Torino scale, which allows astronomers to categorize impact risk on the basis of their probability and the energy released by these collisions. This level does not justify an alert, but calls for “increased attention” on astronomers’ part. The situation is similar to that of Apophis, an asteroid 370 meters in diameter that will pass close to Earth in 2029.
Observations and future studies of 2024 YR4
New observations are under way to fine-tune the orbit of 2024 YR4. Unfortunately, the asteroid is moving away from Earth at top speed, which makes calculating its trajectory a little difficult! It’s possible we’ll have to await its return in 2028 to gain a better idea of impact probability. In any case, what’s certain is that the asteroid will be extensively studied by the scientific community when it next appears, so that we can learn more about its size, its composition and its structure.
Two organizations devoted to asteroid impact avoidance, the International Asteroid Warning Network and the Space Mission Planning Advisory Group, are already assessing what steps will be needed to better characterize this object. Additional observations are scheduled, in particular by the European Space Agency and NASA. The VLT, the world’s largest telescope, located in Chile, will also be put to work.
