M1: Filaments of the Crab Nebula

The Crab Nebula is filled with mysterious filaments. The Crab Nebula
is the result of a star that exploded in 1054 AD. This spectacular supernova explosion
was recorded by Chinese and (quite probably) Anasazi Indian astronomers.
The filaments are mysterious because they appear to have less mass than
expelled in the original supernova and higher speed than expected from a free
explosion. In the above picture, the color indicates what is happening to the
electrons in different parts of the Crab Nebula. Red indicates the electrons
are recombining with protons to form neutral hydrogen, while green indicates
the electrons are whirling around the magnetic field of the inner nebula.
In the nebula's very center lies a pulsar: a neutron star rotating, in this case,
30 times a second.