NASA’s LRO found the biggest new lunar crater ever — 728 feet wide, formed in 2024 while no one noticed

Q: How was McGetchin crater discovered?

NASA's Lunar Reconnaissance Orbiter (LRO) detected it on October 24, 2025, by comparing before-and-after images of the same lunar region. The crater had not been visible in earlier LRO images, placing its formation between April 11 and May 22, 2024.

Sometime in spring 2024 — between April 11 and May 22, to be precise — a rock roughly the size of a five-story building slammed into the Moon near its eastern edge and gouged out a hole 728 feet across and 141 feet deep. The impact scattered debris across roughly four miles of surrounding terrain, leaving the ground beneath it 16 degrees Fahrenheit colder than normal. And nobody knew.

Not for fifteen months.

It was NASA’s Lunar Reconnaissance Orbiter that eventually found it. The spacecraft has been methodically photographing the lunar surface for more than seventeen years, cataloguing more than a thousand newly formed craters since it first switched on its cameras in 2009. On October 24, 2025, comparing before-and-after images of the same stretch of the eastern nearside, researchers led by planetary scientist Mark Robinson at Arizona State University spotted something that simply had not been there before: a fresh scar, as wide as two city blocks, punched into the gray regolith.

The crater now bears a name: McGetchin. It honors Tom McGetchin, a lunar geologist whose research in the 1970s helped shape how scientists understand volcanic ejecta and cratering on airless bodies. The name fits. What his namesake crater revealed turned out to rewrite part of what researchers thought they knew about how impacts reshape planetary surfaces.

The scale of the thing

Two papers published simultaneously in Science Advances on September 16, 2026, lay out what makes McGetchin remarkable. At 222 meters across — about 728 feet — it is the largest newly formed crater ever identified in the solar system in modern monitoring history. That distinction requires some unpacking: scientists have been actively watching parts of the Moon and Mars with orbital cameras for decades, and nothing comparable has been found. The previous record-holders were notably smaller.

The impactor was probably somewhere between three and six stories tall — not vast by solar-system standards, but traveling fast enough and carrying enough momentum to excavate a hole deeper than a ten-story building’s footprint. The collision sprayed ejecta across a radius four times its own diameter and released enough energy to alter the thermal properties of the surrounding regolith permanently. At night, when the Moon’s surface radiates the day’s accumulated heat back into space, the four-mile cold ring around McGetchin drops to temperatures 16°F lower than the undisturbed ground nearby.

That cold patch is a thermal wound. Freshly shattered rock conducts heat differently than the porous, micrometeorite-churned surface layer that accumulates over millions of years. The anomaly will persist for thousands of years — a bruise on a world with no weather to smooth it over.

What the spacecraft found

Robinson’s team — which includes researchers from Intuitive Machines, the Houston-based company behind the IM-1 lunar lander — used LRO’s Narrow Angle Camera and Diviner Lunar Radiometer to characterize both the crater’s geometry and its thermal signature. The radiometer’s nighttime temperature maps made the cold anomaly visible in a way that crater images alone might have obscured, and they confirmed that the disturbed zone extended well beyond the visible rim.

A second paper, led by Benjamin Powell, documents how the impact modified the terrain far beyond the crater itself. Secondary impacts from ejected boulders and compressed soil clods are visible for miles in multiple directions. The ejecta blanket extends further than cratering models had predicted, suggesting that the near-surface regolith in this region was less cohesive than average, allowing debris to travel unusually far before settling.

What “record-breaking” actually means

“Largest newly formed crater ever identified in the solar system in recent times” is a precise statement, but it comes with a boundary condition worth stating clearly. LRO cannot watch every square meter of the Moon simultaneously. It builds coverage over repeated orbital passes across years and decades. An impact of this size could theoretically have occurred in a region imaged infrequently enough that no comparison image existed. The fifteen-month gap between formation and discovery exists partly because LRO was not pointed at this stretch of the eastern nearside during the relevant window, and partly because the detection process relies on systematic comparison of overlapping image pairs.

The method is exhaustive, but it is not instantaneous. The record is the best-documented one, not necessarily the only one.

What the discovery does confirm is something more fundamental: the Moon is not the static world it can look like from Earth. In the seventeen years since LRO first began its patrol, researchers have catalogued more than a thousand fresh craters. Most are tiny — centimeter-scale pits invisible to anything but orbital imaging. McGetchin is orders of magnitude bigger, a reminder that the solar system still occasionally throws something substantial at a surface we tend to think of as ancient and finished.

The gap that no one noticed

Consider what the fifteen-month window means in practice. Between April 11 and May 22, 2024, a boulder the size of a building completed a journey that may have begun in the asteroid belt millions of years ago, or in the debris trail of a long-dead comet. It struck the Moon at tens of thousands of miles per hour. In less than a second, a 728-foot hole appeared on a world that had been looking more or less the same since humans first photographed it from orbit.

Nobody felt it. Nobody detected it. No seismometer registered it. The crater just appeared on the Moon, waited, and let an orbiting spacecraft find it fifteen months later on a routine image comparison.

LRO has been making those comparisons, systematically and patiently, since 2009. It has found more than a thousand craters by doing exactly this — going back, looking again, noticing what changed. McGetchin is the biggest thing it has found yet. The researchers who named it after Tom McGetchin, the geologist who spent his career trying to understand what impacts leave behind, would likely agree: the Moon is still teaching us things.

Frequently asked questions

How was McGetchin crater discovered?

NASA’s Lunar Reconnaissance Orbiter detected it on October 24, 2025, by comparing before-and-after images of the same lunar region. The crater had not been visible in earlier LRO images, placing its formation between April 11 and May 22, 2024.

Why did it take 15 months to find a crater this large?

LRO photographs the entire lunar surface over time but cannot monitor all areas simultaneously. Detection requires comparing overlapping image pairs from different orbital passes; this part of the eastern nearside was not re-imaged with suitable overlap until late 2025.

What makes McGetchin crater a record?

At 728 feet (222 meters) wide, it is the largest newly formed crater ever documented anywhere in the solar system during the modern era of orbital monitoring. Previously identified new craters detected by spacecraft cameras have been significantly smaller.

Is the Moon still being actively hit by space rocks?

Yes. LRO has identified more than 1,000 new impact craters since 2009. Most are very small, but the ongoing survey confirms that cratering is a present-tense process, not only a relic of the solar system’s early bombardment history.

Research published in Science Advances (Robinson et al., DOI: 10.1126/sciadv.aeh7812; Powell et al., DOI: 10.1126/sciadv.aeh9568), September 16, 2026.

Tags: astronomy, nasa, moon, Science Advances, lunar impact, Lunar Reconnaissance Orbiter