Neutron stars are the most extreme objects in the universe that have been proven to exist.  Black holes are very likely, but we’re still not 100% sure about them.  A black hole is like a giant squid in the ocean.  We’re pretty sure they exist, but nobody has caught one.  The neutron star on the other hand is like a blue whale, everybody knows they exist, and they are massive, rare, and beautiful.  Of course, once we know something exists, the next logical step is to figure out how it behaves, to characterize and generalize it, and to identify where it’s...