The Moon is Slowly Shrinking, and That Could Be a Problem: ScienceAlert
It is difficult to observe from Earth, but the Moon shrinks in size as it continues to cool.
At about 45 meters (more than 150 feet) every few hundred million years, it’s not a rapid change, although a new study by researchers in the US suggests it may be enough to be responsible for landslides and earthquakes near Antarctica. For the moon.
What makes this research particularly important is that the study area is where NASA is considering landing future astronauts. If we’re going to build a space station on the Moon, it’s best not to put it in a geologically unstable area.
“Our models suggest that shallow lunar earthquakes capable of generating strong ground shaking in the Antarctic region are likely from slip events on existing faults or the formation of new thrust faults,” says planetary scientist Tom Watters of the Smithsonian Institution.
“The global distribution of emerging thrust faults, their ability to be active, and the potential for new thrust faults to form from ongoing global contraction must be taken into account when planning the location and stability of permanent lunar outposts.”
This study focused on what are known as lobate slopes, which are extended ridges that scientists believe are caused by tectonic activity. Recent images from the Lunar Reconnaissance Orbiter were analyzed along with recordings from seismometers installed during the Apollo missions, which operated until 1977.
The analysis showed that one of the most powerful lunar quakes ever recorded by the Apollo seismometers, a magnitude 5 quake that lasted several hours, could have been caused by one of the lobate scarps observed near the Moon’s south pole — and on the Moon, that doesn’t happen. It doesn’t take much to cause a dangerous landslide.
“You might think that the surface of the moon is dry and covered with gravel and dust,” says geologist Nicholas Schmer of the University of Maryland.
“Over billions of years, the surface has been exposed by asteroids and comets, with the resulting angular fragments constantly being ejected from the impacts.”
“As a result, the size of the reworked surface material can range from a micron to the size of a boulder, but it is all very loosely consolidated. The loose sediments make it very possible for vibrations and landslides to occur.”
For now, scientists are still dealing with a limited amount of data when it comes to the frequency and location of moonquakes, but any insights — like those provided by the results of this new study — will be helpful in planning locations for moonquakes. Future landings on the moon and lunar bases.
“As we approach the launch date of the crewed Artemis mission, it is important to keep our astronauts, equipment, and infrastructure as safe as possible,” says Shamir.
“This work helps us prepare for what awaits us on the Moon — whether that’s engineering structures that can better withstand lunar seismic activity or protecting people from really dangerous areas.”
The research was published in Planetary Science Journal.