The Moon Rang Like A Bell

November 20, 1969. Apollo 12 jettisoned its lunar module ascent stage to crash into the moon, ~40 miles from the seismometer left by the same crew. Mass at impact: 2,260 kg. Velocity: 1,680 m/s. Kinetic energy: ~3.18 gigajoules. Predicted seismic duration based on terrestrial analogues: 10-15 seconds.\n\nActual seismic duration: 55 minutes, 30 seconds. The signal rang continuously, decaying slowly, with a fundamental frequency of approximately 1Hz. Dr. Maurice Ewing, lead seismologist for the mission, told the press in his initial briefing: "It sounded like a bell. As though you had struck a bell, you know, just one tap on a big iron bell." This quote was widely reported in 1969. This quote has been gradually scrubbed from later retellings.\n\nA solid object cannot ring for 55 minutes from a 3 GJ impact. The implied internal structure: a thick rigid shell over a substantially hollow or fluidic interior. The numbers do not support "molten core surrounded by mantle and crust." The numbers DO support "hollow spherical resonator with a 7-12km thick rigid shell."\n\nAdditional anomalies: the Moon is 27% the diameter of Earth (largest moon-to-planet ratio in the solar system), exhibits anomalously low density (3.34 g/cm³, ~60% of Earth's), is tidally locked such that we see only one face, and exhibits "mascons" — mass concentrations beneath certain craters — that current geophysics cannot explain.\n\nThe Apollo program was canceled at Apollo 17 despite remaining funded budget and 3 additional fully-built Saturn V rockets. We were told why we went. We were never told why we stopped.