In the year 1054 a star in the constellation of Taurus exploded in a spectacular supernova so bright it appeared to dominate the sky except for the Sun and Moon for many days. It left behind one of the most brilliant nebulae, listed first in Charles Messier's list of nebulous sky objects. Today we know that the center of the nebula houses the remnant of the explosion: a spinning neutron star called a pulsar. The Crab pulsar is visible in almost every part of the electromagnetic spectrum, and has been a useful astronomical tool. It is still unclear how the the pulsar emits the light that we see.