A routine data-quality check turned up the solar system's largest fresh crater 15 months late
The 2024 strike that punched a 222-metre hole in the Moon slipped past every telescope on Earth and in orbit. It was found by comparing orbiter images months afterwards, and NASA now wants to know what its debris could hit.
The Scientist · Science desk
What happened
- A comet or asteroid the size of a three- to six-storey building struck the Moon's eastern edge sometime between April 11 and May 22, 2024, according to NASA.
- The crater it left, named McGetchin, measures about 222 metres across and up to 43 metres deep, the largest newly formed impact crater found anywhere in the solar system.
- Every telescope on Earth and in space missed the strike as it happened, according to the Associated Press account of the research.
- The crater was picked out of the orbiter's wide-angle images in August 2025, detailed follow-up pictures came last autumn, and the discovery was confirmed early this year.
- Two papers published Wednesday in Science Advances report the crater and a surrounding band of ground whose temperature and texture the impact changed.
Why it matters
- What doesn't add up contradiction New Scientist calls this the largest crater we have watched form in real time, while the Associated Press account says the impact escaped real-time detection; the difference is between watching an impact happen and finding it afterwards in the archive.
- What it limits constraint The once-per-132-years figure is a model output, and a single well-characterised event gives modellers one calibration point for the model.
- Who's exposed exposure Loosened regolith reaches about 31 crater diameters from the rim, so a site picked for its distance from any fresh crater can still sit on ground whose behaviour under a rover wheel has changed.
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Robert Wagner was running a quality check on a mosaic of the Moon when a bright patch ringed by a dark halo stopped him. "I just stopped, dropped everything, and started looking into what that spot was," Wagner said [6]. The halo mattered because it implied material at the surface had been shaken up [7]. Confirmation came from comparing images of the same ground before and after the impact [8].
The Lunar Reconnaissance Orbiter has been circling the Moon for more than 17 years with seven instruments aboard [11]. Models of lunar impact frequency put a crater this size at about one every 132 years [9]; NASA's own estimate is once a century or longer [10]. Divide 17 by 132 and a mission of this length should have expected about 0.13 such events [30]. The crater, named for Thomas McGetchin, a former director of the Lunar and Planetary Institute in Houston, is three times bigger than the previous record holder, which the same orbiter found a decade ago [31][14].
Robinson's team traced churned surface more than 100 kilometres from the rim, according to the Associated Press account of the paper [26]. New Scientist reports the same team's figure as more than 120 kilometres [27]. Take the smaller one: 100,000 metres divided by a 222-metre crater is about 450 crater diameters of modified ground [33]. Robinson said the dust and rocky soil left at a higher angle than expected [28].
Diviner, the orbiter's thermal instrument, found a patch about 7 kilometres wide around the crater that runs roughly 16 degrees Fahrenheit cooler at night than the ground beside it [16][15]. The second paper attributes the cooling to fluffed-up regolith, which is less dense and so holds less heat [17]. "It's really striking that a crater can modify the lunar surface to distances far larger than the crater itself," said Tyler Powell of Johns Hopkins University, an author of that paper [29]. That cold spot spans about 31 times the crater's own diameter [32].
David Paige of UCLA, a co-author, said the team is "now thinking of impacts as a way to garden the regolith" [34]. Robinson puts the overturn rate of the Moon's top two centimetres at once every 80,000 years, faster than previously thought [35], and said the Apollo footprints will "definitely be long gone in that time frame" [36].
The 132-year number comes out of models of how often impacts occur [9]. Powell said having "a baseline for a pristine crater that can serve as our calibration point for how these processes start is really incredible" [20]. Neither paper says whether debris landing 100 kilometres out arrives with enough energy to damage a structure. Robinson said the next step is to calculate the risk of ejected crater material striking NASA's planned moon base [18]. "That information will help engineers harden structures so one won't have to worry about damage, or maybe worry less," he said [19].
At the small end, the smallest craters the orbiter can distinguish are about 30 feet across, made by rocks about 43 inches wide, and the team estimates roughly 140 of those form across the Moon each year [13]. Over the mission it has identified at least 1,000 new impact craters and flagged 100,000 other surface changes [12].
What to watch
- The ejecta risk calculation Robinson describes, and whether it yields a threshold engineers can design a habitat to.
- Whether other archived LRO wide-angle mosaics hold large fresh craters still to be found. More of them would move the modelled 132-year rate.
- Repeat Diviner passes over the cold spot. They would show how fast fluffed regolith settles back.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence78
- Adoption
- Not scored
- Hype gap+15
- Incentives40
- Confidence75
Perspective Coverage
5 publishers- Builder
- Builder 33%
- Operator
- Operator 56%
- Investor
- Investor 11%
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
McGetchin crater is about 222 metres (728 feet) across and up to 43 metres (141 feet) deep.
- [2]
The crater is the largest newly formed impact crater ever found in the solar system.
- [3]
The crater formed on the Moon's eastern edge sometime between April 11 and May 22, 2024, after a comet or asteroid the size of a three- to six-story building hit the surface.
- [4]
The moon strike escaped real-time detection by telescopes on Earth and in space.
- [5]
Robert Wagner, an image-processing specialist from Intuitive Machines who works with the Lunar Reconnaissance Orbiter Camera system, noticed an unusually large bright spot circled by a dark halo while scanning a giant Moon map during a routine data-quality check.
- [6]
"I just stopped, dropped everything, and started looking into what that spot was," said Wagner.
- [7]
The bright spot circled by a dark halo caught Wagner's eye because it implied that surface material in that area had been shaken up.
- [8]
Wagner established the discovery by comparing before and after images of the Moon.
- [9]
According to models of how often impacts occur on the moon, a crater about 222 metres across is expected only about once every 132 years.
- [10]
Scientists estimate that an impact of this magnitude happens on the Moon about once in a century or even longer.
- [11]
For more than 17 years the Lunar Reconnaissance Orbiter has been circling the Moon, using its seven instruments to map topography, surface composition, temperature and the radiation environment.
- [12]
The LRO team has identified at least 1,000 new impact craters over the mission and flagged 100,000 more surface changes from objects hitting the Moon or from ejected debris.
- [13]
The smallest craters scientists can distinguish in LRO images are about 30 feet wide, made by rocks about 43 inches wide, and impacts of that scale are estimated to produce about 140 new craters across the Moon each year.
- [14]
The crater is three times bigger than the previous record-holder found by the LRO a decade ago.
- [15]
Scientists working with LRO's thermal instrument, Diviner, found a 4-mile-wide area around the crater that is about 16 degrees Fahrenheit cooler at night than its surroundings.
- [16]
Researchers measured surface temperature around McGetchin crater and found a spot about 7 kilometres wide that is a handful of degrees colder than the rest of the area during the lunar night.
- [17]
The cooling happens because the impact fluffs up the regolith around the crater, making it less dense and therefore less able to retain heat.
- [18]
Robinson said the next step is to calculate the risk of ejected crater material striking NASA's planned moon base.
- [19]
"That information will help engineers harden structures so one won't have to worry about damage, or maybe worry less," Robinson said.
- [20]
"Having a baseline for a pristine crater that can serve as our calibration point for how these processes start is really incredible," says Tyler Powell.
- [21]
New Scientist describes the crater as the largest that we have ever watched form in real time, and says it was first spotted last year when researchers compared LRO image sets from 2024 and 2025.
- [22]
Two studies on the crater appeared Wednesday in the journal Science Advances; Mark Robinson, chief scientist for the LRO's cameras, was lead author of one, and David Paige of UCLA is a co-author of the other.
- [23]
"This event constitutes a statistically rare, effectively once-in-a-lifetime observation," the scientists wrote in one of the two studies.
- [24]
NASA says the physical changes to the regolith around the crater could affect how rover wheels interact with the surface.
- [25]
"If we're trying to send rovers or astronauts or build things on the moon, we want to understand the properties of the surface," says Powell.
- [26]
The impact churned the lunar surface for more than 66 miles (100 kilometres).
- [27]
The team led by Mark Robinson at Intuitive Machines found that the impact flung dust and rocks more than 120 kilometres from the crater itself.
- [28]
Dust and rocky soil were hurled away at a higher angle than expected, according to Mark Robinson.
- [29]
"It's really striking that a crater can modify the lunar surface to distances far larger than the crater itself," says Tyler Powell at Johns Hopkins University in Maryland.
- [30]
A 17-year mission would expect about 0.13 impacts of this size at a rate of one every 132 years.
- [31]
The crater is named for the late Thomas McGetchin, a former director of Houston's Lunar and Planetary Institute.
- [32]
A 7-kilometre-wide cold spot around a 222-metre crater is about 31 times the crater's diameter.
- [33]
Debris reaching 100 kilometres from a 222-metre crater extends about 450 crater diameters from the rim.
- [34]
"We're now thinking of impacts as a way to garden the regolith - churning the sediments and putting stuff above that's usually below the surface," Paige said in a statement.
- [35]
The LRO's crater discoveries since its 2009 launch show that the moon's top inch (2 centimetres) of soil is being overturned by ejected material every 80,000 years, faster than previously thought, according to Robinson.
- [36]
Contrary to the popular belief that the Apollo moonwalkers' dusty footprints will last forever, they will "definitely be long gone in that time frame," Robinson said in an email.
- [37]
The Lunar Reconnaissance Orbiter's wide-angle images were not identified in the crush of data until August 2025; the spacecraft gathered more detailed pictures last fall, followed by confirmation of the discovery early this year.
- [38]
Roughly 15 months passed between the impact and the identification of the crater in orbiter images.
Sources
4 independent publishers whose own reporting we read for this story.
- discovermagazine.comNewly Discovered "Once-in-a-Century' Moon Crater Larger Than Two Football Fields
1 article · September 17, 2026
- nasa.govNASA’s Moon Orbiter Spots New, ‘Once-in-Century’ Moon Crater
1 article · September 16, 2026
- newscientist.comAsteroid hit the moon and flung rocks 120 kilometres from the crater
1 article · September 16, 2026
- phys.orgNASA spacecraft discovers a huge new crater on the moon
1 article · September 17, 2026
- sciencedaily.comNASA’s Moon orbiter finds a 728-foot crater that wasn’t there before
1 article · September 18, 2026
Topics and entities
Topics
- Lunar Exploration
- Lunar impact cratering
Entities
- Lunar Reconnaissance Orbiter
- Intuitive Machines
- Lunar Reconnaissance Orbiter Camera
- NASA
- Science Advances
- McGetchin crater