Webb Observations Rule Out Moon Impact by Asteroid 2024 YR4 — Close Pass Expected Dec. 22, 2032

New observations from NASA's James Webb Space Telescope have allowed astronomers to rule out a lunar impact by asteroid 2024 YR4 during its close approach on Dec. 22, 2032. After months of evolving impact estimates, the latest data sharpen the asteroid's predicted position and confirm it will pass safely past the Moon.

What changed? The asteroid was first reported to the Minor Planet Center on Dec. 27, 2024, and initially produced nonzero impact probabilities for both Earth and the Moon. Precision measurements from Webb, taken on multiple occasions in early 2025 (including Feb. 18 and Feb. 26) and followed by additional observations, reduced orbital uncertainties. Those new data let scientists narrow the asteroid’s predicted track and rule out a strike on the lunar surface.

Closest approach and size: Current best estimates place 2024 YR4’s nearest passage at roughly 13,200 miles (about 21,200 kilometers) above the Moon’s surface on Dec. 22, 2032 — a distance that is small by celestial standards but comfortably clear of the lunar surface. Telescopic and Webb measurements indicate the asteroid could be as large as ~300 feet (about a 15‑story building).

Risk history: When first discovered, 2024 YR4 briefly appeared on NASA’s Sentry Impact Risk Table and, at its highest assessed concern, reached a computed Earth-impact probability near 3.1%. As more precise observations accumulated in late February and thereafter, teams reduced the odds of an Earth impact to effectively zero. The Moon’s brief window of nonzero impact probability fluctuated with successive data updates before Webb’s most recent measurements allowed scientists to exclude a lunar collision.

Who reported the update? The trajectory refinements and the exclusion of a Moon impact were reported by researchers led by the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, and summarized by NASA in a March 5 blog post. The detailed analysis has not yet appeared in a peer‑reviewed journal.

What would an impact have meant? NASA modeling indicated that even a hypothetical strike by a rock of this size would not alter the Moon’s orbit around Earth, though it would create a visible crater and localized effects on the lunar surface. Given the updated trajectory, such scenarios are no longer considered likely for 2032.

Next steps: Astronomers will continue monitoring 2024 YR4 with ground‑based telescopes and space observatories to further refine its orbit and timing. Continued observations will reduce remaining uncertainties and maintain accurate predictions for the 2032 close approach.

Bottom line: Improved Webb observations tightened the asteroid’s predicted path and removed the possibility of a Moon impact on Dec. 22, 2032. The object will pass well above the lunar surface at an estimated distance of about 13,200 miles.

The High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter captured this image of interstellar comet 3I/ATLAS on Oct. 2, 2025. At the time it was imaged, the comet was about 19 million miles from the spacecraft. The comet didn't come nearly as close to Earth, when it reached a distance of 170 million miles from our planet on Dec. 19.

This image shows the 3I/ATLAS interstellar comet as a bright, fuzzy orb in the center. Traveling through our solar system at 130,000 miles per hour, 3I/ATLAS was made visible by using a series of colorized stacked images from Sept. 11-25, using the Heliocentric Imager-1 (H1) instrument, a visible-light imager on the STEREO-A (Solar Terrestrial Relations Observatory) spacecraft. The colorization was applied to differentiate the image from other observing spacecraft images.

Because it's big enough to be deemed a "city killer," asteroid 2024 YR4 became a source of alarm due to the uncommonly high risk it had of colliding with Earth on Dec. 22, 2032. For a time, it was the only object among more than 37,000 known large space rocks with any chance of hitting Earth anytime soon – with its probability of impact even rising to a record level of 3.1%.That began to change in late February as more precise observations allowed scientists to effectively winnow down the asteroid's odds of impact to a number so low, it might as well be zero.

An exoplanet known as K2-18b achieved a degree of fame in April when a team of astronomers claimed to have found in its atmosphere "the strongest evidence yet" that life exists anywhere else besides Earth. Other scientists have since cast doubt on the findings – putting a damper on the notion that humanity finally had proof that we aren't alone in the cosmos.

This artist's concept shows what exoplanet K2-18b could look like based on scientific data. NASA's James Webb Space Telescope has observed K2-18b, an exoplanet 8.6 times as massive as Earth, revealing conditions that could support life on the exoplanet.

NASA’s Perseverance Mars rover is seen in a "selfie" that it took over on Sept. 10, 2021. Perseverance rover, along with Curiosity, is one of the agency's two car-sized robots exploring the Martian surface for signs that the planet was once habitable. And in September, NASA officials confirmed that one of the rovers’ finds contained a potential biosignature.

A reddish rock nicknamed "Cheyava Falls", with features resembling leopard spots was discovered by NASA's Perseverance rover in Mars’ Jezero Crater in July 2024, in this handout photograph released on September 10, 2025.

The northern lights, also known as the aurora borealis, light up the night sky Nov. 11 east of Denver, Colorado. A powerful geomagnetic solar storm in November blasted Earth and created the conditions necessary to reveal the auroras much further south in the United States than is typical.

A group of friends take photos of the northern lights Nov. 11 as they appear over Clinton Lake in Lawrence, Kansas. After NOAA's Space Weather Prediction Center issued a "severe" geomagnetic storm watch in November, many people in the Northern Hemisphere, which includes the U.S., had an extraordinary opportunity to gaze upon some breathtaking red and green auroras in their own backyard.

In June, the state-of-the-art Vera C. Rubin ground telescope in Chile unveiled its first stunning images of the cosmos. This particular image combines 678 separate images taken by the observatory in just over seven hours of observing time. Combining many images in this way clearly reveals otherwise faint or invisible details, such as the clouds of gas and dust that comprise the Trifid nebula (top) and the Lagoon nebula, which are several thousand light-years away from Earth.

An image of the asteroid 2024 YR4 taken by the European Southern Observatory's Very Large Telescope, released on February 25, 2025, shows a frame of the asteroid's path through the night sky in January 2025, observed at infrared wavelengths with the HAWK-I instrument.

Firefly's Blue Ghost lunar lander captures its shadow on the moon's surface after completing a successful landing March 2 near a volcanic feature on the moon called Mons Latreille. The vehicle became the first of two landers manufactured by a U.S. company to reach the moon is 2025 in crucial missions to lay the groundwork for NASA to return humans to the lunar surface in the years ahead.

Athena, the lunar lander on Intuitive Machines' IM-2 mission, captured this image of the moon's surface with Earth seen in the distance ahead of a March 6 landing attempt. While the lander was the second U.S. vehicle to reach the moon within a week, it ultimately landed on its side, which hindered much of its mission.

NASA astronaut Suni Williams is helped out of a SpaceX Dragon spacecraft March 18 following a return to Earth after a nine-month stay at the International Space Station. She and NASA astronaut Butch Wilmore crewed the Boeing Starliner, which had launched in June 2024 on a failed test flight that was meant to return them to Earth a few days later.

Butch Wilmore reacts after he and Suni Williams and two other astronauts splashed down March 18 in a Crew Dragon space capsule following their return to earth from the International Space Station off the coast of Florida. The astronauts' extended stay at the orbital outpost dominated the news cycle for months.

A SpaceX support team member is seen airborne while working to lift the SpaceX Dragon capsule that returned the Starliner astronauts and two others onto a recovery vehicle following its landing off the coast of Florida.

This picture shows the crew of a privately-funded mission known as Fram2, from left to right, mission specialist and medical officer Eric Philips, mission commander Chun Wang, pilot Rabea Rogge and vehicle commander Jannicke Mikkelsen on March 19, 2025 in Hawthorne, California. Launched March 31 from Florida using a SpaceX Dragon capsule, the mission became t first ever human spaceflight over the Earth's polar regions.

Pop musician Katy Perry emerges April 14 from Blue Origin's New Shepard capsule in West Texas following a brief flight to the edge of space. Perry was part of an all-women crew that also included broadcast journalist Gayle King that took the ride from Blue Origin's facility called Launch Site One. The high-profile launch attracted plenty of headlines and even drew some backlash from those who viewed the mission as a wasteful publicity stunt.

Blue Origin's New Shepard rocket carrying astronauts Aisha Bowe, Amanda Nguyen, Kerianne Flynn, Gayle King, Katy Perry, and Lauren Sanchez lifts off April 14 from Launch Site One near Van Horn, Texas. Blue Origin has since launched five more human spaceflights on the New Shepard in 2025.

This photo depicts a United Launch Alliance Atlas V rocket carrying the latest batch of Amazon's broadband satellites on Dec. 16 to low-Earth orbit after launching from the Cape Canaveral Space Force Station in Florida. Formerly called Project Kuiper, the venture has since been renamed Amazon Leo. Since its debut April launch, Amazon Leo has deployed 180 of 3,000 satellites planned for its first constellation, which could challenge SpaceX's Starlink.

A group of Blue Origin employees with their friends and families gather on the beach in Cape Canaveral for the launch of Blue Origin's second New Glenn rocket in 2025. Following its January debut, the rocket launched for the second time Nov. 13 from Launch Complex 36 at Cape Canaveral Space Force Station, sending NASA's twin ESCAPADE spacecraft on their trek to Mars.

Darkness falls Nov. 9 as a Blue Origin New Glenn rocket is prepped for its second-ever launch from the Cape Canaveral Space Force Station. Blue Origin is developing the towering rocket for heavy-lift missions that could see Jeff Bezos' company compete with Elon Musk and SpaceX.

The SpaceX Starship spacecraft sits Oct. 12, 2025 atop the Super Heavy booster before sunrise as preparations continue for its 11th test flight from the company's complex in Starbase, Texas.

A SpaceX Super Heavy booster carrying the Starship spacecraft lifts off Oct. 13, 2025, on its 11th ever test flight at the company's launch pad in Starbase, Texas. The launch was Starship's fifth of 2025, and second consecutive successful test flight following a year that was early on marked by explosive failures. SpaceX is developing the rocket for future missions that would help NASA astronauts land on the moon and also potentially transport the first humans to Mars.

This image from the James Webb Space Telescope shows asteroid 2024 YR4. It’s exceedingly faint right now, reflecting about as much light as an almond at the distance of the moon. Without Webb, scientists would have needed to wait until 2028, during the asteroid’s next passage through the inner solar system, before refining their knowledge of its trajectory.