For half century, people thought they understood the Moon: a stationary, airless and waterless landscape with few mysteries to solve. However, orbiting instruments and robotic missions have proven otherwise. The solar system’s best-studied satellite is more elaborate than it seems, and many fundamental questions remain open.
NASA will soon return to the Moon with the Artemis program. While Artemis II and III will be satellite orbit missions, Artemis IV will send astronauts to the surface for the first time since the Apollo era. The ambitious plan is to lay the foundations for a sustainable presence that will generate a steady stream of data and samples.
Some of the lunar mysteries will be solved thanks to the gigantic number of samples and technology provided. Not all answers will come in time, and the results will likely come slowly, but they have never been closer to a solution. Here is a list of mysteries that can be solved using realistic scenarios in the next 10 to 20 years.
What is the origin of the Moon?
The prevailing theory of the Moon’s origin is that it was formed after a Mars-sized planet collided with the proto-Earth about 4.5 billion years ago. Some of the material ejected from this impact clumped and solidified, forming the satellite that orbits Earth today.
However, this hypothesis is based on elaborate simulations and a restricted set of samples brought back by Apollo 50 years ago. Direct access to up-to-date, unaltered rocks combined with state-of-the-art analytical techniques can provide much stronger evidence. Of course, it will be necessary to access deep materials, such as fragments of the mantle exposed in craters or impact zones, and to reconstruct the chronology of the antique lunar magma ocean. The hardest part will be getting there; the rest is science.
How much water is there on the Moon and what is it like?
Half a century ago it was believed that the Moon was completely arid. Scientists have since determined that there is ice in the permanently shadowed craters at the South Pole, and some of the water is trapped in crystalline form in minerals on the surface. The substantial question is how many there are and whether they are suitable for apply in future lunar bases.
One of the 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 cleaner deposits can be found. At best, the resources are bountiful and capable of being converted into oxygen or fuel. In the worst case, it is so dispersed that it would be impossible to extract it.
What is the internal structure of the Moon?
The Moon’s internal structure remains one of its biggest blind spots. Apollo seismometers have detected deep and shallow moonquakes, but the data is thin and comes from only one region. Current gravity and thermal models offer a sketch of the interior, but are far from a detailed map.
Eternal human presence would enable scientists to install seismometers in areas never before explored and expand their global reach. With a state-of-the-art network, the resolution of the Moon’s interior would significantly raise, and scientists could better determine the size of the core, the structure of the mantle and the distribution of residual heat. It won’t be a perfect picture, but it will certainly be the most complete one so far.
Why is the Murky Side so different?
If the Moon is a single body, why is its far side so uneven and jagged, while the near side is smoother and covered with basalt seas? This asymmetry is one of the greatest contemporary lunar mysteries. Several models, ranging from differences in initial heat to changes in magma ocean crystallization or Earth’s gravitational effects, try to explain it, but none quite fit.
The return to the Moon opens up the possibility of the first human expeditions to the surface of the Murky Side. If samples are taken, researchers will be able to determine its age, composition and thermal evolution – key data to solving a mystery that has remained unanswered for half a century.
What happened to the lunar magnetic field?
The Apollo samples revealed something unexpected: Many of them are magnetized, as if the Moon had a powerful internal dynamo. However, based on what is known about its size and interior, the satellite appears too tiny and chilly to maintain a forceful global field for very long.
The up-to-date lunar era could shed airy on this mystery with fresh samples from different regions and more precise magnetic measurements. With well-dated rocks and better data about the interior, researchers will be able to reconstruct when the dynamo existed and what its intensity was.
Moon: midpoint or space laboratory
Unlike the era of Apollo, today the Moon is not the final destination, but the starting point for a up-to-date stage of exploration. What will happen in the next decade will not only solve unsolved mysteries; it will also redefine how we understand rocky worlds, how planets form, and how far human research can go when they return to a familiar place with up-to-date questions.
Humanity may not have 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 hands full of moon rocks.
This story originally appeared on WIRED in Spanish and was translated from Spanish.