Nothing catastrophic is happening to the moon right now, but it is going through several slow, measurable changes that scientists find genuinely interesting. The moon is shrinking, quaking, drifting away from Earth, and losing the internal heat that once gave it a magnetic field. These changes unfold over millions of years, but they have real consequences for future lunar exploration and, eventually, for life on Earth.
The Moon Is Shrinking
As the moon’s interior slowly cools, it contracts, much like a grape shriveling into a raisin. This process has been happening since the moon formed roughly 4.5 billion years ago, and it has caused the surface to develop wrinkle-like features called lobate scarps. These are essentially cliffs created when sections of crust get pushed up and over neighboring sections along thrust faults. Data from the Lunar Reconnaissance Orbiter has revealed thousands of these scarps scattered across the surface, confirming that the contraction is global rather than limited to specific regions.
The total shrinkage is modest by planetary standards. The moon’s circumference has decreased by roughly 150 feet (about 50 meters) over the last several hundred million years. But even small amounts of contraction generate enormous stress on a rigid, rocky body with no atmosphere or water to absorb it. That stress has to go somewhere, and it does: straight into the crust, cracking and faulting the surface.
Moonquakes Are Surprisingly Strong
The moon experiences four distinct types of quakes. Deep moonquakes happen hundreds of miles below the surface and are caused by Earth’s gravitational pull stretching the moon’s interior. Thermal quakes occur near the surface when rock expands and contracts through the extreme temperature swings between lunar day and night. Meteoroid impacts cause their own seismic events. But the most dramatic type comes from the shrinking itself: shallow moonquakes originating 12 to 19 miles below the surface that can register up to 5.5 on the Richter scale and last more than 10 minutes.
On Earth, a 5.5-magnitude quake is strong enough to crack walls and knock items off shelves. On the moon, the lack of water in the rock means seismic energy doesn’t dissipate quickly. Instead, the vibrations ring through the crust for far longer than they would on our planet, making even moderate quakes a serious engineering concern for any future structures built there.
The South Pole Is Especially Unstable
This matters right now because NASA’s Artemis program plans to land astronauts near the lunar south pole, where permanently shadowed craters may contain water ice. Unfortunately, this region sits squarely in a zone of active faulting. The epicenter of one of the strongest moonquakes ever recorded by the Apollo seismic instruments was located in the south polar region, and the cluster of possible epicenter locations overlaps with several Artemis III candidate landing sites.
One young thrust-fault scarp sits within the de Gerlache Rim 2 candidate landing region, and modeling suggests this fault could have produced a quake matching the recorded magnitude. Shackleton crater, another area of interest for exploration, has interior walls that models predict are susceptible to landslides. The Nobile Rim 1 landing region faces similar risks. None of this makes south pole missions impossible, but it adds a layer of geological hazard that mission planners have to account for.
The Moon Is Drifting Away From Earth
Every year, the moon moves about 1.5 inches (3.8 centimeters) farther from Earth. The mechanism is tidal friction. The moon’s gravity raises tides on Earth, but because our planet rotates faster than the moon orbits, the tidal bulge gets pulled slightly ahead of the moon’s position. This offset creates a gravitational tug that slowly transfers rotational energy from Earth to the moon, nudging it into a progressively higher orbit.
The practical effect on Earth is that days are getting longer. Billions of years ago, an Earth day lasted less than 13 hours. The current rate of change is tiny, roughly 1 to 2 milliseconds per century, but it is constant and cumulative. Over hundreds of millions of years, this will significantly alter Earth’s rotation, tidal patterns, and the stabilizing influence the moon has on our planet’s axial tilt.
Its Magnetic Field Is Gone
The moon once had a global magnetic field generated by a churning, liquid iron core, similar to the dynamo that powers Earth’s magnetic field today. That dynamo shut down somewhere between 1.5 billion and 1 billion years ago as the core cooled and solidified. Today the moon’s core still has a molten outer layer surrounding a solid iron inner core, but there isn’t enough convective motion to sustain a magnetic field. The remaining field strength is essentially zero, less than 0.1 microteslas (Earth’s field is roughly 25 to 65 microteslas).
Without a magnetic field, the lunar surface is fully exposed to cosmic radiation and charged particles from the sun. Instruments aboard China’s Yutu-2 rover measured an average radiation dose on the surface of about 1,369 microsieverts per day. That’s 2.6 times higher than what astronauts experience aboard the International Space Station, which at least benefits from partial shielding by Earth’s magnetosphere. For context, Earth’s natural background radiation delivers roughly 6 to 7 microsieverts per day. A person standing on the moon receives in one day what someone on Earth absorbs in about six months.
Temperature Swings Are Extreme
Without an atmosphere to distribute heat, the moon’s surface temperature swings wildly depending on whether it faces the sun. In full sunlight, temperatures reach about 260°F (127°C), hot enough to boil water at reduced pressures. In darkness, they plummet to around minus 280°F (minus 173°C). That’s a swing of more than 500°F over the course of a single lunar day, which lasts about 29.5 Earth days.
These cycles stress rock at the surface, causing thermal expansion and contraction that generates its own category of shallow moonquakes. They also pose a persistent challenge for equipment and habitats, which must survive repeated thermal cycling without cracking seals or degrading materials.
Lunar Dust Is Toxic and Destructive
The moon’s surface is covered in regolith, a layer of fine, jagged dust and rock fragments created by billions of years of meteoroid impacts pulverizing the bedrock. Unlike dust on Earth, which gets rounded and smoothed by wind and water, lunar dust particles have razor-sharp edges. They also carry a persistent electrostatic charge that makes them cling to virtually any surface they contact.
For equipment, the dust is an abrasion and coating hazard. It gets into mechanical joints, scratches optical surfaces, and interferes with electronics. For humans, the risks are more serious. The particles are fine enough to penetrate deep into the lungs, reaching the tiny air sacs where gas exchange happens. Once there, they can directly damage cells, trigger inflammatory responses, and potentially allow nanoscopic particles to enter the bloodstream. The dust contains nanophase iron that may generate reactive oxygen species on contact with human tissue, a mechanism similar to what causes silicosis in miners exposed to crystalline quartz dust on Earth. Apollo astronauts reported irritation after brief exposure inside their spacecraft; long-duration stays would require rigorous dust management.
Hundreds of Meteoroids Hit Every Year
With no atmosphere to burn up incoming debris, meteoroids of all sizes slam directly into the lunar surface at full speed. NASA’s monitoring program, running since 2005, has detected more than 300 strikes, and extrapolations suggest hundreds of detectable impacts occur every year. Most are small, but occasional large events produce craters up to 20 meters wide. A March 2013 impact produced a flash visible from Earth through a backyard telescope.
For any permanent presence on the moon, this represents a constant low-level bombardment risk. Combined with the seismic activity, radiation exposure, dust toxicity, and thermal extremes, it paints a picture of a world that is geologically active and environmentally hostile in ways that aren’t obvious from simply looking up at it on a clear night.