Pulsars Have Crunchy Crust, Supersmooth Interiors, Study Suggests

Pulsars, the left-over remains of exploded stars, are considered some of the most accurate natural timekeepers in the universe, but even these excellent cosmic clocks aren't perfect. A new study suggests that pulsars occasionally exhibit a "glitch" in their timing because they are filled with a "superfluid" that can flow over any surface without friction. When massive stars grow old and die, they explode, sometimes leaving behind a neutron star — a small, incredibly dense nugget of collaps