00:00Do not worry, but the moon is shrinking and writhing, a bit like a raisin that becomes dry.
00:08This happens because our natural satellite has kept its internal heat for more than 4 billion years.
00:15But its core is gradually cooling down and becoming denser.
00:19Unlike the soft skin of a raisin, the surface of the moon is quite friable.
00:24This fragility leads to the formation of cracks, where different sections of the crust meet against each other,
00:31giving rise to what scientists call moon tremors.
00:36So far, our satellite has shrunk by about 45 meters in circumference.
00:42This change is so minor that it does not affect the appearance of eclipses or phases of the moon.
00:48The tidal cycles will not be affected either, because the mass of the moon has not really changed.
00:55This shrinking process will not affect us directly here on Earth, but that does not mean that everyone is safe.
01:03The moon tremors caused by this shrinking process have been worrying researchers for years.
01:10During the famous Apollo missions, NASA astronauts left seismometers at different points on the moon.
01:17These devices were unable to detect the seismic activity of the lunar surface with exceptional precision.
01:26The equipment worked for several years and managed to record more than 12,000 lunar earthquakes with magnitudes ranging from 2 to 5.
01:36Until 1977, the team was able to identify four distinct types of tremors.
01:42Some, such as those caused by meteorite impacts, were relatively easy to isolate.
01:48However, the cause of superficial lunar earthquakes remains a mystery to scientists,
01:54which could be an obstacle for future lunar missions.
01:58As the name suggests, superficial earthquakes occur relatively close to the surface,
02:04most often from 50 to 220 km below the crust.
02:08Recent research suggests that these tremors would be triggered by the compression of the lunar surface,
02:13leading to the formation of overlapping cracks, where a layer of surface is pushed up and above another.
02:19This study also identified the epicenters of the most powerful earthquakes.
02:23It all started in the region of the South Pole, precisely where we want to settle.
02:29Our interest in the South Pole of the moon reached its peak in 2023,
02:33when the Chandrayaan-3 mission from India managed to land there and deployed a rover to explore the region.
02:40NASA also plans missions in this area, with the ambitious goal of sending astronauts there for the first time.
02:47The Artemis-3 mission, scheduled for 2026, identified 13 sites of potential lunar eclipses in the South Pole, represented here by blue squares.
02:57One of the options is inside a geological formation called Gerlach crater, a strategic area for exploration.
03:05This region could receive ice, because some parts remain permanently in the dark,
03:11while being close enough to the sunny areas, essential for collecting solar energy.
03:16The pink dots on this map indicate the most powerful epicenters of lunar eclipses recorded by the Apollo mission.
03:24This suggests that the clashes in this area could be relatively recent and active, posing a real danger for the Artemis-3 crew.
03:33The astronauts of this mission will stay in lunar orbit for 30 days, and two members will descend to the surface for about a week at the South Pole.
03:42Their exits will be particularly arduous, due to the extreme temperatures in these permanently darkened regions.
03:50The presence of lunar eclipses and potential landslides adds even more risk to this mission,
03:57because these phenomena are much more frightening than our Earthquakes.
04:02The most powerful lunar eclipse ever recorded had a magnitude of 5.7.
04:08This could seem insignificant compared to similar eclipses recorded in 2023 in countries like Chile,
04:15Colombia or Papua New Guinea, which did not cause major damage.
04:20But the situation is different on the Moon.
04:23As gravity is much lower than on Earth, a slight tremor can have much more striking effects,
04:29because you are not as solidly anchored to the lunar surface as you are to the Earth.
04:33Seismic waves can therefore cause larger movements on the surface.
04:40In addition, the duration of lunar eclipses is much longer.
04:43Our Earthquakes usually last between 10 and 30 seconds, some reaching sometimes two minutes.
04:49On the other hand, a lunar eclipse can last much longer.
04:53The Moon, being a solid, rigid and dry sphere, resonates powerfully when it is shaken,
04:59without any natural means of dissipating this energy.
05:02Lunar eclipses can last up to 10 minutes or more, with small shakes that last for hours.
05:10These new discoveries concerning lunar eclipses will not really change Artemis 3's potential landing sites or the duration of the mission.
05:20The reason for this is that precisely determining the frequency of eclipses in a specific region is an extremely complex task.
05:28Scientists know that these shallow eclipses are rare and pose a low risk for short-term missions to the lunar surface.
05:37However, the situation changes considerably when a long-term habitation is envisaged on the Moon,
05:43which could happen sooner than we thought.
05:47The Artemis 3 mission is a crucial step towards space colonization.
05:52China, on the other hand, plans to establish a permanent lunar base in the South Pole by 2040.
05:58Their strategy involves the use of 3D printing and the manufacture of bricks from the lunar soil in order to build this base.
06:06It is a fascinating prospect.
06:08But setting up such an infrastructure involves many challenges,
06:12including the management of intense cosmic radiations, lack of water and, of course, long-term Moon shakes.
06:22Over billions of years, the surface of the Moon has been bombed by asteroids and comets,
06:27causing the constant detachment of pieces and debris.
06:30As a result, the material on the surface is relatively soft and not compacted.
06:35When earthquakes occur, the slopes in these areas can be subject to landslides or the opening of new faults.
06:43Future colonies located too close to these unstable slopes could put their inhabitants at risk.
06:49The lunar dust adds another complication.
06:52Because without erosion or water for smoothing, it can become as hard as glass.
06:58To better understand the impact and risks of Moon shakes on future inhabitants,
07:03space agencies must map and collect new seismic data,
07:07not only in the South Pole, but on our entire satellite.
07:12In 2025, the FSS plans to deploy two of the most precise seismometers ever built in the Schrödinger crater,
07:23located on the hidden side of the Moon.
07:26Studying what is happening on this soil is crucial to understand the complex structure of the Moon and its internal dynamics.
07:34Scientists are still trying to determine whether the absence of seismic activity recorded on the hidden side of the Moon
07:40is due to an inability of current instruments to detect it,
07:44or to interference from fusion materials in the mantle.
07:48Once this question is clarified, it will be easier to understand the superficial shaking of the Moon
07:54and to assess their implications for the future colonies installed on our natural satellite.
08:01You may have heard that the Earth was also shrinking, but this is a different process.
08:06The Moon shrinks mainly because its core cools naturally.
08:10The core of the Earth also cools, but our planet has tectonic plates, unlike the Moon.
08:16Thus, the energy of the Earth's core moves its plates or frees itself through volcanic eruptions.
08:23The Earth also loses mass due to atmospheric loss.
08:27Our planet loses about 45,000 tons of mass per year,
08:31mainly due to our fleeing atmosphere.
08:34Indeed, Earth's gravity is not enough to retain light particles such as hydrogen and helium,
08:40which escape into space.
08:43However, these figures are not alarming,
08:46given that the atmosphere of our planet weighs more than 5 billion billion tons,
08:51or a figure of 15 zeros.
08:53In other words, it would take many times the current age of the universe for it to evaporate completely.
09:00I don't know about you, but I breathe more freely all of a sudden.
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