On April 2, 2025, NASA announced an updated assessment of asteroid 2024 YR4’s trajectory, increasing the estimated probability of a lunar impact on Dec. 22, 2032, from 1.7% to 3.8%. If a collision occurs, the asteroid could create a crater up to 2 km wide, unleashing an estimated 5.2 megatons of TNT-equivalent energy, but it poses no risk to Earth or the Moon’s orbit.
New infrared observations from NASA’s James Webb Space Telescope on March 26 refined the size estimate of the asteroid to 53-67 meters, about the height of a 10-story building. Webb’s thermal emission data offered a more precise measurement than previous visible-light estimates.

The cosmic body was first detected in December 2024, briefly raising concerns about a possible Earth impact with an initial 1.3% probability. From January 27 to February 20, 2025, it held a Torino Scale rating of 3. However, continued observations have refined its trajectory, reducing the impact probability to just 0.004%, confirming no significant risk for at least the next century.
Asteroid 2024 YR4 will become too faint for ground-based telescopes after mid-April, but Webb will observe it again between April 20 and May 16. The asteroid’s 2028 flyby will be a key opportunity to refine its orbit and better assess the likelihood of a lunar impact in 2032.
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Moon craters witness a past full of impacts
The Moon’s scarred surface is a striking geological record of billions of years of asteroid impacts. In its early history, the young Moon endured a relentless bombardment of massive space rocks, shaping its rugged landscape.
Over time, larger objects fragmented into smaller debris, and while impacts continued, they were increasingly caused by micrometeoroids. However, minor asteroids still strike the Moon, and when they do, their high-speed collisions release bright flashes of light, visible even from Earth.
Some of these recent impacts have been captured in detail, offering valuable insight into the Moon’s ongoing bombardment. One of the most striking events occurred on March 17, 2013, when a small boulder-sized object struck Mare Imbrium, producing a flash nearly ten times brighter than any previously recorded.
A rare lunar impact was captured during the total lunar eclipse of January 21, 2019, when an asteroid struck the Moon at nearly 61,000 km/h. The event was observed at 4:41 a.m. GMT, producing a bright flash visible to amateur astronomers and leaving a crater up to 15 m wide. Spanish astronomers later confirmed the event using the Moon Impacts Detection and Analysis System (MIDAS).

If asteroid 2024 YR4 collides with the Moon, it could carve out a crater between 500 and 2,000 m wide, reshaping the lunar surface. While some astronomers suggest the impact flash could be visible from Earth, others argue that the Moon’s brightness might make it harder to see. Beyond the spectacle, Professor Karri Muinonen of the University of Helsinki warns that the collision could eject debris into space, potentially harming satellites and human activities.
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A threat to future lunar activities
Although asteroid impacts on the Moon are now rare, smaller meteoroids strike its surface daily. The Earth’s atmosphere acts as a protective shield, burning up most of these incoming rocks before they reach the ground. But the Moon has no such defense.
With meteoroids traveling up to 72 kilometers per second (160,000 mph), even tiny fragments can carve out craters, ejecting lunar soil and rock at high velocities. For future lunar missions, this poses a significant risk.

NASA operates the Lunar Impact Monitoring Program to better understand this threat. By observing the Moon from Earth, scientists can track impact flashes caused by meteoroids and gather crucial data on the frequency and intensity of these collisions. This research helps refine impact hazard models, essential for designing safer lunar habitats and spacecraft.
Thick layers of compacted 3D-printed regolith could be used to shield future lunar habitats from meteoroid impacts and radiation. Pressurized surface vehicles equipped with external manipulators could offer astronauts a safer way to explore and work in hazardous environments, much like deep-sea submarines do on Earth.

An even more promising solution lies underground: lunar lava tubes. These vast tunnels, some over 300 meters wide and buried beneath 40 meters of basalt, offer protection from impacts, radiation, and extreme temperature swings, making them an ideal location for long-term human settlements.
If an asteroid like 2024 YR4 were ever to collide with the Moon, habitats inside lava tubes would remain shielded from the direct blast and flying debris, further reinforcing their role as safe havens for future lunar explorers and permanent settlements.
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