The Moon's Ancient Magnetism
The moon is now a dead body, but it seems once to have generated its own magnetic field. Since then it has been shifted with respect to its spin axis-perhaps by collisions with moon-orbiting satellites
Corals as Paleontological Clocks
Banding on certain corals evidently represents annual, monthly and daily growth. Ancient corals thus provide clues to the length of the year in past eras and to changes in the earth's rotation
The Earth's Magnetism
The fact that the grains of ancient rocks are lined up like tiny compass needles has led to the astonishing conclusion that the earth's magnetic poles have wandered and reversed