ESA
Asteroide 2024 YR4
Astronomers have a tight deadline to determine the real threat posed by 2024 YR4, which could collide with the Moon on December 22, 2032. The James Webb Space Telescope will soon observe the asteroid and, with new data, the probability of a lunar impact could increase by up to 30%.
The asteroid was detected for the first time on December 27, 2024, by the ATLAS telescope, in Chile.
Initial projections pointed to the asteroid hitting Earth in 2032, which made it, at the time, the most dangerous asteroid known.
However, later observations quickly reduced the probability of a terrestrial impact to almost zero. Despite this, it persists, with a current estimate of 4.3% probability of a direct impact.
Although the risk to Earth has largely disappeared, a lunar impact could have . The asteroid, about 60 meters in diameter, would release energy equivalent to 6.5 TNT megatoneladasopening a 1 km wide crater on the lunar surface.
According to Professor Paul Wiegert, from the University of Western Ontario, such an event would be the largest lunar impact in the last 5,000 years.
The collision could also launch up to 108 kg of lunar material into space, part of which could reach Earth, creating an impressive meteor shower. Although these meteorites pose no danger to people on the ground, the debris could pose a significant risk to satellites and space infrastructure.
Wiegert’s team estimates that the lunar ejecta stream could expose Earth-orbiting satellites to impacts equivalent to several yearss, or up to a decade, of typical meteoroids in a short period of time.
The possibility of a lunar impact has caused concern among agencies responsible for safety in space. The ejected debris could threaten not only satellites orbiting the Earth, but also lunar facilitiessuch as NASA’s future Lunar Gateway and other planned surface operations.
O Exact level of risk will depend on point of impactbut experts warn that even a localized rain of lunar material could damage sensitive equipment or endanger astronauts.
Second Richard Moisslhead of the Planetary Defense Office at the European Space Agency ESA, a lunar impact would certainly leave a new observable crater and could result in the arrival of new lunar meteorites to Earth. However, the Moon’s orbit would not be affected.
Race against time
Right now, astronomers are awaiting a crucial observation window with JWST to refine the asteroid’s trajectory and impact probability. The asteroid will become visible again in 2026, offering a new opportunity for precise measurements.
As explained to the astronomer Andrew Rivkinfrom Johns Hopkins University, there is an 80% probability that upcoming observations will reduce the lunar impact hypothesis to less than 1%. However, there is a 5% chance that this probability increase drastically, exceeding 30%.
Given the limited time frame and the asteroid’s faint brightness, planning diversion missions is a challenge. Some contingency plans came to fruition consider the use of nuclear devices to alter the asteroid’s trajectory, although such a measure is considered a last resort.
“Observations made with the most powerful telescope we currently have are invaluable,” said Rivkin. “Learning how to make the most of JWST data will contribute to future urgent responses to the asteroid threat.”
As astronomers prepare for their next opportunity to observe 2024 YR4, the world waits to find out if the Moon will be spared — or whether we will attend a unparalleled cosmic event in the last millennia.
