[math-fun] Moon as tape recorder for events on Earth

FYI -- It would be fabulous to find bits from the k-T boundary (65Mya) on the Moon. http://www.airspacemag.com/daily-planet/ancient-life-moon-earth-180954282/ Ancient Life on the Moon ­ From Earth The possibility that terrestrial fossils are preserved in Moon rocks makes lunar exploration even more appealing. It was once said the Moon acts as a cosmic tape recorder, quietly and continuously collecting a detailed history of the Earth-Moon corner of the universe over the last 4 billion years. Now we are discovering that this geologic tape recorder holds an even more impressive collection of “tunes” than we had previously imagined.