The Hollow Moon: Four Claims, Visualised · Signals from the Periphery

THE HOLLOW MOON · FOUR CLAIMS, FOUR DATASETS
'An artificial satellite, which is mostly hollow' (p. 8)
the bell, the shell, the core and the 400:1 ratio, each run against its own instrument
the mass, the moment of inertia, the seismic Q, the core and the recession are measured
the shell's density and I/MR² are arithmetic on the measured mass
the coda model and the recession history are published models, shown with their spread
cut the Moon · strike it · weigh the core · run the eclipse

Evidence

fact ⇄ what kind of claim · live

'Mostly hollow' (p. 8); 'a dense armoring of about 20 miles in thickness' (p. 218); 'a tiny metal core ... 680 km in diameter' (p. 219); 'the kind of signature one sees when a hollow metallic object is struck' (p. 217); '400 times smaller ... and 1/400th the distance' (p. 216)

the book's own words with page numbers, almost all quoted from Wilson 1975 and Knight & Butler 2005

REPORTED

Mass 7.346×10²² kg, mean radius 1,737.4 km, bulk density 3,344 kg/m³; I/MR² 0.393112 ± 0.000012 (LLR + GRAIL, Williams et al. 2014)

the mass fixes the density any shell must have; the moment of inertia says where the mass sits: below 0.400 means toward the centre, not a shell

MEASURED

Apollo 12 LM impact 20 Nov 1969, 73 km from the station, peak after ~7 min, visible ~55 min; Apollo 13 S-IVB 15 Apr 1970, 135 km, peak ~7 min, 3 h 20 min (Apollo 12/14 Preliminary Science Reports); Q of the upper crust 3,000-5,000; Apollo basalt in the lab: Q ~60 in air, ~3,300 outgassed (Tittmann et al. 1975)

the slow rise is scattering, the long tail is dryness; a struck shell does neither

MEASURED

A fluid outer core of radius ~330 km and a solid inner core ~240 km (Weber et al. 2011), 1-2% of the mass; Lunar Prospector's 340 ± 90 km (Hood et al. 1999), the number the book quotes

the small core is what a giant impact predicts, and the book cites it as evidence for the opposite

MEASURED

Angular-size ratio Moon/Sun today 0.91-1.05; recession 3.83 cm/yr (LLR); 620 Ma rhythmites put the Moon at 58.2 R⊕, 2.45 Ga at ~55 (Williams 2000)

the ratio is a moment in a known motion; the window in which it straddles 1 is computed, not assumed

EXACT

The coda envelope (Dainty & Toksöz diffusion) at a published diffusivity; the distance history between the rhythmite points; the Sun's slow growth

published models with a spread; the misfit and the interpolation are drawn, not hidden

MODELLED

Whether four numbers that each have an ordinary measurement behind them, and a fifth that is an arithmetic slip, amount to an artefact or to a list

the one question this bench refuses to close for you

READING

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