Asteroid 2024 YR4, until recently thought to have a chance of striking Earth on December 22, 2032, could now be headed for the moon instead, according to new data.
After new observations, 2024 YR4 is thought to have a diameter of about 98–213 feet (30–65 meters). The James Webb Space Telescope studied it in March and found it to be about 197 feet (60 meters). That’s about the same width as a football field.
Chance Of Lunar Impact
The stony asteroid — first discovered on December 27, 2024, when it was passing just 1.5 million miles (2.5 million kilometers) — is one of the largest objects in recent history that could impact the moon, according to a paper accepted for publication in The Astrophysical Journal Letters.
A lunar impact would be a book for scientists, who know little about the relationship between the size of an asteroid and the size of its resulting impact crater — despite the moon being covered in craters. “If it does, it will give scientists a rare chance to study how the size of an asteroid relates to the size of the crater it creates — something we haven’t been able to measure directly before,” said Bryce Bolin, the lead author. For now, there’s a roughly 2% chance YR4 could collide with the moon.
Shaped Like A Hockey Puck
Data from the Gemini South Observatory in Chile and the Keck Observatory in Arizona revealed that the asteroid rapidly rotates backward and may be shaped like a hockey puck. “This find was rather unexpected since most asteroids are thought to be shaped like potatoes or toy tops rather than flat disks,” said Bolin. “2024 YR4 is a solid rock, likely chipped off from a larger rubble-pile asteroid in the central Main Belt between Mars and Jupiter.”
That 2024 YR4 appears to come from the main asteroid belt is a surprise. “This region was not previously known to produce asteroids on Earth-crossing paths,” said Bolin. It’s thought that gravitational interactions with Jupiter have forced it into the vicinity of Earth.
Rare Chance To Study An ‘Earth Crosser’
2024 YR4 came to prominence in late January 2025 when the International Asteroid Warning Network placed the asteroid on its watch list after calculations of its orbit suggested it had over a 1% probability of hitting Earth in 2032.
However, more calculations showed that it had dropped below 1% by late February. At the end of February, NASA announced that the chances of 2024 YR4 striking Earth during a close pass in 2032 were near zero.
“Studying this asteroid was vitally important in understanding the population of Earth crossers that have the potential to be Earth impactors and are poorly understood,” said Bolin.
Apophis, ‘God Of Chaos’
The news about 2024 YR4 comes as astronomers prepare for a very close pass of a much larger asteroid, 99942 Apophis, in exactly four years. The 1,100-foot (340-meter) wide asteroid will get to within 20,000 miles (32,000 kilometers) of Earth on Friday, April 13, 2029, creating a once-in-a-thousands-year opportunity for science. It will be so close that it will be seen eyed by observers across Western Europe and Western Africa. When Apophis was discovered in 2004, scientists calculated it might strike Earth in 2029, 2036 or 2068 — hence its “God of Chaos” nickname.
NASA and the European Space Agency will send spacecraft to orbit Apophis before, during and after its close pass, just in case its trajectory changes and it becomes Earth-bound.
Wishing you clear skies and wide eyes.
