This core is hidden beneath a crust that accumulated in
a second phase of moon formation, planetary scientist Robin Canup reported November 11 at a meeting of the American Astronomical Society's Division for Planetary Sciences.
The nine - foot - tall London clock uses a slowly rotating torsional pendulum, ticks once every 30
seconds, and tracks hours, sidereal and solar years, centuries,
phases of the
moon, and the zodiac — and happens to be hauntingly beautiful.