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.…