美国航天局发现月球多年来最大的新坑：未来的月球基地要小心了

In many people's imagination, the moon is a silvery, silent world.

In reality, it's more like a war zone.

Asteroids and comet fragments keep slamming into it, leaving fresh scars beside the ancient craters.

This week NASA announced it had found the largest fresh impact crater seen on the moon since at least 2009.

The crater is about 222 meters wide — more than twice the length of an American football field.

A planetary geophysicist at the University of Maryland described it as a monster of a crater, at least in modern times.

It was found by NASA's Lunar Reconnaissance Orbiter.

The probe has circled the moon for more than ten years, taking a vast number of photos.

Going through those photos, scientists noticed a crater they had never seen before.

The crater was first spotted in October 2025.

By comparing satellite images from before and after the impact, they narrowed its timing to between April 11 and May 22, 2024.

The object that struck the moon was roughly nine to twenty-one meters across.

It hit the lunar surface at tremendous speed, instantly giving off a dazzling flash.

The energy released in that moment was equal to fifteen thousand five hundred tons of explosives.

The crater was named McGetchin crater, in honor of lunar scientist Tom McGetchin.

It sits at the edge of the Sea of Crises, a plain of frozen lava more than five hundred kilometers long on the moon's eastern side.

The two studies behind the finding were published this week in the journal Science Advances.

By their estimate, an impact of this size happens on average only once every 132 years.

If it's that rare, why does it deserve attention?

Because the United States and China are racing to see who can put astronauts back on the moon first.

If the plans hold, by the 2030s the lunar south pole could have several nuclear-powered bases.

Astronauts would stay there for several weeks, or even several months.

That makes an old question very real: how often does the moon actually get hit?

Earth, too, is constantly bombarded by asteroids and comet fragments.

But the atmosphere slows them down and burns up objects smaller than about nine meters across.

If a bigger object explodes in midair, the shock wave can hurt people and buildings nearby.

The moon has almost no atmosphere, so it is defenseless against visitors of every size.

Spent rocket boosters sometimes fall onto its surface, and space rocks crash down all the time.

Satellites in lunar orbit, telescopes on Earth, even the astronauts of Artemis II have seen brief flashes of light on the moon's surface.

Based on those observations, scientists estimate that objects the size of monster-truck tires blast out around 140 nine-meter craters on the moon each year.

These objects can travel at tens of thousands, or even hundreds of thousands, of kilometers an hour.

The odds of a base being hit by such an object on any given day are low; the odds of a bigger hit are lower still — but not zero.

A physicist who studies impacts at the University of New Mexico said he absolutely thinks this is a significant risk to long-term operations on the moon.

And this new crater reveals something even more unsettling.

An asteroid doesn't need to hit a base directly to cause a catastrophe.

In an impact, rocks of all sizes are thrown out, and when they land they gouge out craters of their own.

The researchers found that most of the debris landed near the crater's rim.

But around the crater there are also splattered streaks, like an ink-splash painting, reaching more than a hundred kilometers away.

In other words, ground far from the impact site was also left badly battered.

Worse, small objects under a few tens of meters are very hard to detect in advance.

That means missions designed to deflect an asteroid or smash it apart might not be able to launch in time.

Put another way, if a moon base sits in the path of a small rock, it may well have no way to dodge it.

That physicist's conclusion is simple: the risk from small stuff is very real.

If humans want to live on the moon for the long haul, they'll have to factor in rocks that could fall from above at any moment.

If you were in charge of designing the first moon base, would you build it underground, or find another way?