Probability of Asteroid 2024 YR4 Impacting the Moon May Increase to 30%

Astronomers have a limited timeframe to determine if they will intervene to stop asteroid 2024 YR4 from colliding with the moon in 2032. A brief observation period utilizing the James Webb Space Telescope is set to commence in February, as new findings indicate that the potential for impact is rising to over 30%, posing a significant threat to satellites and future lunar infrastructures.

Discovered late last year, 2024 YR4 quickly emerged as the most probable asteroid to strike Earth. The worst-case scenario initially estimated a collision probability of 1 in 32 for 2032. However, further observations have nearly eliminated the chance of an Earth impact, leaving a 4 percent possibility of a collision with the moon, which could endanger numerous vital satellites orbiting Earth due to debris.

Despite the considerable risk associated with this asteroid, space agencies have yet to take action, although NASA researchers are exploring potential deflection strategies, such as deploying a nuclear charge near the asteroid.

The asteroid has recently moved out of range for Earth’s telescopes, limiting astronomers’ ability to obtain further data on its orbit until it reappears in 2028, which may not allow enough time to execute a deflection mission.

Fortunately, the James Webb Space Telescope (JWST) anticipates a brief operational window to observe the asteroid in February 2026 and again in April 2024, offering a critical opportunity to plan a deflection mission. Andrew Rivkin from Johns Hopkins University in Maryland remarked, “By 2028, it will be in close proximity, so capturing data in early 2026 grants us additional time.”

This advantageous positioning will enable JWST to observe 2024 YR4, which follows a distinct orbit around Earth, undetectable by other ground-based telescopes, but the observation will still be challenging, as the asteroid is expected to be dim, even for JWST’s highly sensitive instruments. There will be two narrow windows for observation on February 18th and 26th.

Rivkin and his team computed how new data regarding the asteroid’s positions and velocities could alter the existing understanding based on these observations. Their findings indicate an 80% likelihood of reducing the probability of a lunar impact to under 1%, while there is a 5% chance that the risk could increase to 30% or higher. JWST should have a chance to repeat these observations in 2027, but this will provide less time for decision-making, according to Rivkin.

Nonetheless, it remains uncertain whether space agencies would opt to plan missions in the event of increased risks. “The question of whether planetary defense extends to the moon is entirely new, and different agencies may have varied responses,” Rivkin noted. “If a company operates many satellites, they might advocate for a particular course of action.”

Richard Moisle from the European Space Agency indicated that while the current budget does not allocate for deflection or reconnaissance missions regarding the asteroid, they will reevaluate if next year’s observations indicate a heightened risk of collision. “We chose to delay our decision until next year to allow for a thorough evaluation of our options,” Moisle stated.