Millisecond Pulsars, Magnetars, and Black Holes: The Wickedly Cool Stellar Undead

The most massive stars burn the fastest and brightest and die spectacularly, exploding as supernovae and leaving behind some of the most fantastic objects in the Universe: neutron stars and black holes. These are fascinating objects themselves, but ever since Bell and Hewish discovered the first pulsar over 40 years ago, we've realized that we can use the neutron stars especially as powerful tools for basic physics and astrophysics as well. Specialized "timing" observations of the MSPs are providing a wealth of science, including new tests of general relativity, amazing probes of the interstellar medium, constraints on the physics of ultra-dense matter, new windows into the evolution of stellar systems both simple and complex, and the promise of a direct detection of massive ripples in space-time, gravitational waves.