Wen-Jie Xie

The theory that handles ordinary atomic nuclei beautifully hits a dead end when we venture into the heart of a neutron star. There, matter density goes off the charts, and old formulas start lying.

A cosmic "caliper" will soon measure a neutron star to within a hundred meters. For an object a couple dozen kilometers across, that's like measuring the thickness of a human hair from a kilometer away. A neutron star is the remnant of an exploded supernova.