The Moon got hit so hard, part of it got colder

Something enormous slammed into the Moon.

The collision blasted out a 728-foot-wide crater, threw lunar material across the surface and disturbed terrain more than 60 miles away. But when scientists took the temperature afterward, they discovered something even stranger.

A four-mile-wide patch of the Moon around the new crater is now about 16°F colder at night than the surrounding ground.

And the reason is basically what happens when you fluff a pillow.

How did scientists find this new Moon crater after it got hit?

They found it almost by accident.

On October 24, 2025, Robert Wagner, an image-processing specialist working with NASA's Lunar Reconnaissance Orbiter, was performing what NASA describes as a routine data-quality check. He was comparing enormous collections of before-and-after images when one unusually large bright spot surrounded by a dark halo jumped out at him.

NASA eventually determined that a comet or asteroid had struck the Moon's eastern edge sometime between April 11 and May 22, 2024. Nobody had witnessed the collision as it happened.

The newly named McGetchin crater is about 728 feet across, roughly the length of two football fields, and 141 feet deep.

NASA estimates a lunar impact this large happens only about once a century or even less often.

So scientists had found a spectacular new hole in the Moon.

Then they looked at its temperature.

Why is the Moon crater surrounded by a cold spot?

Because the impact didn't just excavate a crater. After the Moon got hit, it changed the texture of the ground around it.

NASA's Lunar Reconnaissance Orbiter carries an instrument called Diviner that measures temperatures on the lunar surface. When scientists examined the area around McGetchin, Diviner revealed a roughly four-mile-wide region that was about 16°F colder at night than nearby terrain.

The culprit is the Moon's loose surface material, called regolith.

When that space rock hit, the enormous force of the collision shook, churned and loosened the regolith around the crater. Scientists describe the process as essentially fluffing it up.

And fluffy Moon dirt behaves differently than compact Moon dirt.

How can fluffy dirt make part of the Moon colder?

Think about what happens when you loosen up a tightly packed material.

The disturbed lunar soil became less dense, with more space between its particles. That changes how efficiently heat moves through it and how much heat it can hold onto after the Sun goes down.

So during the lunar night, the loosened material around McGetchin loses its heat faster than the more compact terrain nearby.

The result is almost like a thermal fingerprint of the impact.

You can have two patches of Moon sitting beside each other under essentially the same conditions, but one becomes noticeably colder because a violent collision changed the physical structure of its dirt.

And here's the part that surprised scientists: the cold area is vastly larger than the crater that caused it.

How far did the impact change the Moon?

Much farther than you'd guess by looking at the hole.

Scientists found evidence that material thrown from the impact disturbed the lunar surface more than 60 miles away. The thermal cold spot itself stretches about four miles across.

That means an impact doesn't simply punch a neat hole in the Moon and call it a day.

It can alter the texture, density and temperature behavior of terrain far beyond the crater rim.

That's especially important now because humans are preparing to spend considerably more time up there.

Why does a cold Moon crater matter to astronauts?

Because different lunar soil can behave differently underneath a spacecraft, habitat or rover.

NASA specifically notes that these impact-driven changes could affect how rover wheels interact with the lunar surface. Understanding where impacts have loosened the regolith could therefore become increasingly important as humans and robots spend more time traveling across the Moon.

There's another reason scientists are excited about McGetchin.

We've been watching the Moon closely enough that we have pictures of this area before the crater existed.

That gives researchers something they almost never get with an enormous impact crater: a before-and-after experiment performed by nature itself.

The Moon may look frozen and unchanging when you see it hanging over your backyard.

It isn't.

Space rocks are still hitting it. New craters are still appearing. The lunar surface is still being rearranged.

And every once in a while, something hits it hard enough that you can measure the collision with a thermometer.

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