How do we know about the Moon's interior?

Our understanding of the Moon's interior primarily comes from seismic data collected by instruments placed on the lunar surface during the Apollo missions. These seismometers recorded moonquakes, allowing scientists to infer details about the Moon's internal structure, including the presence of a partially molten layer beneath the crust. Additionally, analysis of lunar samples brought back by the Apollo missions, as well as remote sensing data from various lunar orbiters, has contributed to our knowledge of its composition and geological history. Together, these methods provide a comprehensive picture of the Moon's interior.