What Is the New Lunar Crater McGetchin and How Did It Form?
A new crater named McGetchin appeared on the Moon after a comet or asteroid roughly 10–20 meters (30–60 feet) across — about the size of a humpback whale — struck the lunar surface sometime between April and May 2024. NASA's Lunar Reconnaissance Orbiter (LRO) captured before-and-after images of the same patch of surface during its monthly monitoring, giving scientists a rare direct look at a fresh impact. The crater is about two soccer fields across, and craters of this size are only expected roughly once every 132 years.
How the impact was detected
The detection relied on repeat imaging rather than a single observation. Because LRO monitors the Moon on a monthly cycle, it photographed the surface before the event and again afterward. Comparing the two images revealed a crater that had not existed in the earlier frame.
This before-and-after method is what makes the find unusual. Most lunar craters are ancient and dated indirectly; here, scientists know the impact happened within a narrow window of weeks.
What formed the crater
- Impactor size: roughly 10–20 meters (30–60 feet), compared in the source to a humpback whale.
- Impactor type: a comet or asteroid.
- Timing: between April and May 2024.
- Crater size: about two soccer fields across.
- Name: McGetchin, after an Apollo-era lunar scientist.
The cold spot around the crater
Follow-up thermal imaging found a large cold spot surrounding the warm crater. The explanation is in the surface material itself: impacts puff up the loose lunar sediment, called regolith, making it less dense. Less dense regolith retains heat poorly, so the disturbed area reads as colder than its surroundings.
The key point is scale. The thermal signature affected an area much larger than the visible crater, meaning the blast disturbed ground well beyond the rim.
Why this event matters
The McGetchin impact informs two areas of lunar science:
- Surface impacts — a directly observed, well-timed crater gives a real-world test case for how impacts excavate and scatter material.
- Evolution of the Moon's surface — the oversized thermal footprint shows that a single impact reshapes a region larger than the crater alone, which matters for reading the age and history of lunar terrain.
The source also notes a broader takeaway: the event is a reminder to be thankful for Earth's atmosphere, which burns up or breaks apart most incoming objects of this size before they reach the ground.
Where to find the images
The before-and-after images and the full explanation are published as a NASA Astronomy Picture of the Day entry, credited to NASA/GSFC/Intuitive Machines, with text by Keighley Rockcliffe. APOD notes that its main NASA site is moving from apod.nasa.gov to science.nasa.gov/apod, and that its image-submission email address has changed.