WHO: The Crab Nebula is a supernova remnant in
the Milky Way Galaxy.
WHAT: The Crab contains a powerful "pulsar wind
nebula," the result of energetic particles and magnetic
fields expelled from a pulsar, the dense core of what
was once a massive star.
WHERE: Found in the constellation Taurus, the "bull,"
the Crab Nebula is about 6,000 light years from Earth.
Taurus is visible during the winter in the Northern
WHEN: Chinese astronomers, and possibly others
elsewhere in the world, noted the appearance of the
Crab supernova in the sky in 1054 A.D.
HOW: Pulsars are rapidly spinning objects so dense
that a mass equal to that of the Sun is packed into a
diameter of about 12 miles (the Sun is 870,000 miles
across). The pulsars’ rapid spin combines with their
ultra-strong magnetic fields to create powerful generators,
forming pulsar wind nebulas that extend over
many light years.
WHY: By studying how pulsars transfer their rotational
energy into their surroundings, astronomers
are able to better understand objects ranging from
newly formed stars to disks around supermassive
from NASA's Hubble
from NASA's Spitzer