Messier 1 - The Crab Nebula

The first entry in Chuck’s “not-a-comet” catalogue is the supernova remnant colloquially called “The Crab Nebula.” First discovered by English astronomer John Beavis in 1731, Charles-In-Charge later spotted it and thought it was Halley’s comet. When he realized his mistake, he decided to create a list of things that look like comets but aren’t—and the Messier Catalogue was born.

In 1054, Chinese astronomers recorded what they called a “guest star” that slowly faded from view. That was actually the supernova explosion that created the now six-light-year-wide Crab Nebula 6,500 light years away in Taurus. By my possibly faulty calculations, that means the edge of this thing is racing away from the point of the explosion at about 22 million miles per hour! It left behind a pulsar, the Crab Pulsar to be specific, which is visible in this image:

 The Crab Pulsar is the super-dense, rapidly spinning core of the star that exploded. The pulsar is only 12 miles in diameter, but it has a mass 1.4 times that of the sun. It is so dense—and its gravity so intense—that all its protons and electrons have fused together to become neutrons, thus forming what scientists call a “neutron star.”

It spins at the insane rate of 33 revolutions per second. That means that a point on its equator moves at a speed of almost 4.5 million miles per hour. Its powerful magnetic field is not aligned with the rotational poles of the neutron star, and the poles of that field spew copious amounts of light and subatomic particles. That beam sweeps by us 33 times per second, which is what gave rise to the name “pulsar.” If it were a note, it would be a slightly sharp low C near the bottom of the range of human hearing.