For half a century humans thought they understood the moon: a static, airless, waterless landscape without many mysteries to solve. But orbiting instruments and robotic missions have proven otherwise. The most studied satellite in the solar system is more complex than it seems, and many fundamental questions remain open.
NASA is about to return to the moon with the Artemis program. While Artemis II and III will be missions to orbit the satellite, Artemis IV will put astronauts on the surface for the first time since the Apollo era. The ambitious plan is to lay the groundwork for a sustained presence that will generate a steady stream of data and samples.
Some lunar mysteries will be solved because of the abundant samples and the technology being delivered. Not all the answers will come at once, and the results will probably be slow in coming, but they’ve never been closer to being solved. Here is a list of enigmas that could be clarified, with realistic scenarios, in the next 10 to 20 years.
What Is the Origin of the Moon?
The dominant theory of the moon’s origin proposes that it arose after the collision of a Mars-sized planet with a proto-Earth some 4.5 billion years ago. Some of the material ejected by that impact clumped together and solidified to form the satellite that orbits Earth today.
However, this hypothesis depends on complex simulations and a limited set of samples brought back by Apollo 50 years ago. Direct access to new, unaltered rocks, combined with modern analysis techniques, could provide much stronger evidence. Of course, it will be necessary to access deep materials, such as mantle fragments exposed in craters or impact zones, and to reconstruct the chronology of the ancient lunar magma ocean. The hard part will be getting there; the rest is science.
How Much Water Is on the Moon—and What Is It Like?
Half a century ago it was believed that the moon was completely dry. Scientists have since established that there is ice in the permanently shadowed craters at the south pole and that some of the water is trapped in crystalline form within minerals on the surface. The big question is how much there is and whether it is usable for future lunar bases.
One of first tasks of future Artemis missions will be to explore these craters. If they find ice, they will need to determine whether it is mixed with regolith, whether it forms compact slabs, or whether there are purer deposits to be found. In the best-case scenario, the resource is abundant and processable for oxygen or fuel. In the worst case, it is so dispersed that extracting it would be unfeasible.
What Is the Moon’s Internal Structure?
The internal structure of the moon remains one of the great blind spots. Apollo seismometers detected deep and shallow moonquakes, but the data are sparse and come from only one region. Current gravitational and thermal models offer a sketch of the interior, but are far from a detailed map.
A sustained human presence would allow researchers to install seismometers in areas never before studied and expand global coverage. With a modern network, the resolution of the lunar interior would increase dramatically, and scientists could better define the size of the core, the structure of the mantle, and the distribution of residual heat. It won’t be a perfect image, but it will be the most complete one to date.
Why Is the Dark Side so Different?
If the moon is a single body, why is its far side so rugged and jagged while its near side is smoother and covered in basaltic seas? This asymmetry is one of the great contemporary lunar enigmas. Several models attempt to explain it, ranging from differences in initial heat to variations in the crystallization of the magma ocean or the gravitational effects of Earth, but none quite fits.
The return to the moon opens the possibility of the first human expeditions to the surface of the dark side. If samples are obtained, researchers will be able to determine its age, composition, and thermal evolution, key data to solve a mystery that has been unanswered for half a century.
What Happened to the Lunar Magnetic Field?
The Apollo samples revealed something unexpected: Many are magnetized, as if the moon had had a powerful internal dynamo. But based on what is known about its size and interior, the satellite seems too small and cold to have sustained a strong global field for very long.
The new lunar era may shed light on this enigma thanks to fresh samples from diverse regions and more precise magnetic measurements. With well-dated rocks and better data on the interior, researchers will be able to reconstruct when the dynamo existed and how intense it was.
The Moon: Midpoint or Space Laboratory
Unlike the Apollo era, today the moon is not the final destination, but the starting point for a new stage of exploration. What happens in the next decade will not only solve outstanding mysteries; it will also redefine how we understand rocky worlds, how planets form, and how far human exploration can go when it returns to a familiar place with new questions.
Humanity may not get all the answers, but for the first time in half a century we will be asking the right questions, in the right place, and with our hands full of moon rocks.
This story originally appeared on WIRED en Español and has been translated from Spanish.
