A near-Earth asteroid called 2024 YR4 has been closely monitored in the past couple of months as its odds of impacting Earth in 2032 rose to around 3%. After the latest observations from ESO’s Very Large Telescope (VLT), the odds of impact dropped to around 0.001%.
2024 YR4 was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) station at Río Hurtado on December 27, 2024.
Between 40 to 90 m in diameter, the asteroid made a close approach to Earth at a distance of 828,800 km (515,000 miles) two days before its discovery.
2024 YR4 is now moving away and its next close approach will take place on December 17, 2028.
Because of its size and likelihood of impact on December 22, 2032, the asteroid quickly rose to the top of ESA’s risk list, a catalogue of all space rocks with any chance of impacting Earth.
“Because of the uncertainties, the orbit of the asteroid is like the beam of a flashlight: getting broader and broader and fuzzier in the distance,” said ESO astronomer Olivier Hainaut.
“As we observe more, the beam becomes sharper and narrower. Earth was getting more illuminated by this beam: the probability of impact increased.”
The new VLT observations, together with data from other observatories, have allowed Dr. Hainaut and colleagues to constrain the orbit enough to all but rule out an impact with Earth in 2032.
“The narrower beam is now moving away from Earth,” Dr. Hainaut said.
The impact probability reported by ESA’s Near-Earth Objects Coordination Centre is around 0.001% and the asteroid no longer tops ESA’s risk list.
As 2024 YR4 is moving away from Earth, it has become increasingly faint and difficult to observe it with all but the largest telescopes.
“VLT has been instrumental in observations of this asteroid because of its mirror size and superb sensitivity, as well as the excellent dark skies at ESO’s Paranal Observatory in Chile, where the telescope is located,” the astronomers said.
“This makes it ideal to track faint objects such as 2024 YR4 and other potentially dangerous asteroids.”
“Unfortunately, the same Paranal’s pristine dark skies that made these crucial measurements possible are currently under threat by the industrial megaproject INNA by AES Andes, a subsidiary of the US power company AES Corporation.”
“The project is planned to cover an area similar in size to that of a small city and be located, at the closest point, about 11 km from the VLT.”
“Due to its size and proximity, INNA would have devastating effects on the quality of the skies at Paranal, especially due to light pollution from its industrial facilities.”
“With a brighter sky, telescopes like the VLT will lose their ability to detect some of the faintest cosmic targets.”
