When looking at the night sky, you may not realize it.
But our moon is actually shrinking, and this could be disastrous for NASA.
According to a new study, the moon is shrinking because its dense metallic core is gradually cooling.
As a result, the lunar surface is shrinking and becoming more fragile and, in turn, more prone to seismic tremors known as “moonquakes.”
If these tremors trigger landslides, they could pose a danger to NASA’s Artemis astronauts when they eventually land on the moon, University of Maryland scientists warn.
The circumference of Earth’s moon shrank more than 150 feet as its core gradually cooled over the past several hundred million years. The photo shows the southern region of the moon with blue boxes indicating the proposed locations for the upcoming Artemis III landing. Magenta dots indicate possible epicenters of a very strong lunar earthquake in the early 1970s
According to the team of experts, the Moon has been shrinking very gradually in the 4.4 billion years since its formation.
Its circumference has shrunk by more than 150 feet as its core has cooled over the past several hundred million years.
“The main reason the Moon is shrinking is because the interior of the Moon is still hot and cooling,” Dr Thomas R. Watters, a geologist at the National Air and Space Museum in Washington DC, told MailOnline.
“As the interior cools, its volume shrinks and the crust, the outermost rock layer, adapts to the change.”
Just as a grape wrinkles when it is reduced to a raisin, the moon also develops wrinkles as it shrinks.
But unlike the flexible skin of a grape, the moon’s surface is fragile, causing faults to form where sections of the crust collide with each other.
This is causing lunar earthquakes and could cause landslides that would endanger the inhabitants of the Moon.
“As we approach the launch date of the manned Artemis mission, it is important to keep our astronauts, our equipment and our infrastructure as safe as possible,” said study author Nicholas Schmerr, a geologist at the University of Maryland.
“This work helps us prepare for what awaits us on the Moon, whether it’s engineering structures that can better withstand lunar seismic activity or protect people from really dangerous areas.”
For their study, scientists linked a group of faults located in the south polar region of the Moon to one of the most powerful lunar earthquakes recorded by the Apollo seismometers, back on March 13, 1973, called event N9.
Using models to simulate the stability of surface slopes in the region, the team found that some areas were particularly vulnerable to landslides due to seismic shaking.
Scientists say moonquakes have happened before and could happen again. Here, the arrows point to ‘scarps’ (long structures interpreted as tectonic in nature and the result of a thrust fault) at the moon’s south pole.
Pictured is a portion of the inner wall and floor of Shackleton Crater at the lunar south pole. Rockfalls (white arrows) suggest that recent seismic events were experienced in the crater
Space agencies are generally interested in landing in the southern region of the moon (pictured) because of the rich reserves of water ice there.
Experts say the Moon’s continued contraction has caused notable surface deformation in its south polar region.
It just so happens that the lunar south is where the Artemis III mission intends to land, the first mission to take humans to the moon in more than 50 years.
Later in the Artemis program, probably after 2030, NASA aims to establish a base camp in the lunar south.
Space agencies are generally interested in landing in the southern region of the Moon because of the rich reserves of water ice found there.
It could be a source of drinking water for lunar explorers and could help cool equipment, or decompose to produce hydrogen for fuel and oxygen for breathing.
But the resulting moonquakes and landslides have the potential to destroy the Artemis base camp, including buildings and infrastructure.
The study’s authors are concerned about shallow moonquakes (SMQs), which occur near the moon’s surface, only about a hundred kilometers deep in the crust.
Artemis Base Camp: By the end of this decade, NASA aims to establish a base camp in the southern region of the Moon (artist’s impression)
Artemis is the successor to NASA’s Apollo program of the 1960s and 1970s. In this famous NASA photo, astronaut Buzz Aldrin Jr. poses for a photo next to the American flag on the moon during the Apollo 11 mission. on July 20, 1969.
Like earthquakes on Earth, they can be strong enough to damage buildings, equipment, and other man-made structures.
But unlike earthquakes, which tend to last only a few seconds or minutes, shallow moonquakes can last hours or even an entire afternoon.
Researchers will continue to map the moon and its seismic activity, hoping to identify more places that could be dangerous for human exploration.
Although the next moon landing was recently pushed back to 2026, it’s still relatively early, especially considering we’re still learning about our lunar neighbor.
“A slight seismic shock may be all that is needed to trigger regolith landslides,” the team warns in their paper, published in The Planetary Science Magazine.
“When preparing and locating permanent outposts, the possibility of strong seismic events due to active thrust faults must be taken into account, as they pose a possible danger to future robotic and human exploration of the south polar region. “.