Is the Moon Really Shrinking and Cracking Apart?
April 18, 2026
Yes, the Moon is actively shrinking as its core cools and contracts, causing massive cracks called thrust faults to spread across its surface. Scientists have recently mapped over 1,000 new lunar scarps—cliff-like fractures that can stretch hundreds of kilometers and tower up to 100 meters high.
How the Moon Is Contracting
The Moon’s shrinkage isn’t a new phenomenon—it’s been happening for approximately 4 billion years. As the Moon’s interior cools, it contracts like a grape turning into a raisin. However, unlike a grape’s flexible skin, the Moon’s brittle crust can’t accommodate this shrinkage smoothly. Instead, it fractures and buckles, creating the dramatic cliff-like structures scientists call thrust faults or lunar scarps.
These aren’t minor surface features. Some of these scarps extend for hundreds of kilometers across the lunar landscape and rise to heights of 100 meters or more. The Moon has effectively been tearing itself apart from the inside out, and we’re only now beginning to understand the full extent of this geological activity.
The Discovery of 1,000 New Cracks
Recent scientific mapping efforts have revealed over 1,000 previously unknown lunar scarps scattered across the Moon’s surface. This discovery significantly expands our understanding of how geologically active the Moon remains today. The mapping was made possible through high-resolution imagery and advanced analysis techniques that can detect even subtle changes in the lunar terrain.
These newly discovered fractures provide compelling evidence that the Moon’s contraction is an ongoing process, not just an ancient geological event. The distribution of these scarps across the lunar surface suggests that the shrinkage is happening globally, affecting virtually every region of our natural satellite.
Moonquakes: The Shaking Moon
Perhaps most surprisingly, the Moon’s contraction triggers seismic activity—actual moonquakes. These aren’t brief tremors like most earthquakes on our planet. Moonquakes can last for more than 10 hours, creating prolonged periods of lunar surface instability.
The extended duration of moonquakes occurs because the Moon lacks the water and atmospheric conditions that help dampen seismic waves on Earth. Once the Moon starts shaking, it continues reverberating for hours, like a struck bell ringing in the vacuum of space.
Implications for Future Lunar Missions
The discovery of widespread lunar scarps and ongoing moonquakes raises important questions about NASA’s Artemis program, which aims to establish a permanent human presence on the Moon. Particularly concerning is the planned location for lunar bases near the Moon’s south pole, where some of the most significant fault lines cluster.
The concentration of thrust faults in this region means future lunar inhabitants could face regular moonquakes and ongoing geological instability. Mission planners must now account for these geological hazards when selecting landing sites and designing lunar infrastructure.
The Moon’s Ongoing Evolution
The Moon’s contraction represents a fundamental aspect of planetary evolution that we’re still learning to understand. While the Moon appears static and unchanging from Earth, it’s actually a dynamic world undergoing continuous geological transformation. This shrinkage will likely continue for millions of years as the lunar core gradually cools to match the temperature of surrounding space.
FREQUENTLY ASKED
How much has the Moon shrunk over time? â–¾
The Moon has contracted by approximately 50 meters in radius over the past few hundred million years as its interior has cooled and solidified.
Are moonquakes dangerous to astronauts? â–¾
While moonquakes are generally weaker than earthquakes, their extended duration and the Moon's lack of atmosphere to dampen vibrations could pose risks to lunar structures and equipment.
Will the Moon eventually stop shrinking? â–¾
The Moon will continue shrinking until its core completely cools and reaches thermal equilibrium with space, a process that will take millions more years to complete.
