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
Hemisphere.
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
black holes.
X-rays from
NASA's Chandra
Optical data
from NASA's Hubble
Infrared emision
from NASA's Spitzer
