When a massive star dies, first there is a supernova explosion. Then, what’s left over becomes either a black hole or a neutron star.

That neutron star is the densest celestial body that astronomers can observe, with a mass about 1.4 times the size of the sun. However, there is still little known about these impressive objects. Now, a Florida State University researcher has published a piece^[1] in Physical Review Letters arguing that new measurements related to the neutron skin of a lead nucleus may require scientists to rethink theories regarding the overall size of neutron stars.