Just when it seemed the summer movie season had ended,
two of NASA’s Great Observatories have produced their own
action movie. Multiple observations made over several months
with NASA’s Chandra X-ray Observatory and the Hubble Space
Telescope captured the spectacle of matter and antimatter
propelled to nearly the speed of light by the Crab pulsar, a
rapidly rotating neutron star the size of Manhattan.

“Through this movie, the Crab Nebula has come to life,” said
Jeff Hester of Arizona State University in Tempe, lead author
of a paper in the September 20 issue of The Astrophysical
Journal Letters. “We can see how this awesome cosmic
generator actually works.”

The Crab was first observed by Chinese astronomers in 1054
A.D. and has since become one of the most studied objects in
the sky. By combining the power of Chandra and Hubble, the
movie reveals features never before seen in still images. By
understanding the Crab, astronomers hope to unlock the
secrets of how similar objects across the universe are

Bright wisps can be seen moving outward at half the speed of
light to form an expanding ring, visible in both X-ray and
optical images. These wisps appear to originate from a shock
wave that shows up as an inner X-ray ring. This ring consists
of about two dozen knots that form, brighten and fade, jitter
around, and occasionally undergo outbursts that give rise to
expanding clouds of particles, but remain in roughly the same

“These data leave little doubt that the inner X-ray ring is
the location of the shock wave that turns the high-speed wind
from the pulsar into extremely energetic particles,” said
Koji Mori of Penn State University in University Park, a
coauthor of the paper.

Another dramatic feature of the movie is a turbulent jet that
lies perpendicular to the inner and outer rings. Violent
internal motions are obvious, as is a slow motion outward
into the surrounding nebula of particles and magnetic field.

“The jet looks like steam from a high-pressure boiler,” said
David Burrows of Penn State, another coauthor of the paper,
“except when you realize you are looking at a stream of
matter and anti-matter electrons moving at half the speed of

The inner region of the Crab Nebula around the pulsar was
observed with Hubble on 24 occasions between August 2000 and
April 2001 at 11-day intervals, and with Chandra on eight
occasions between November 2000 and April 2001. The Crab was
observed with Chandra’s Advanced CCD Imaging Spectrometer and
Hubble’s Wide-Field Planetary Camera.

NASA’s Marshall Space Flight Center in Huntsville, Ala.,
manages the Chandra program, and TRW, Inc., Redondo Beach,
Calif., is the prime contractor. The Smithsonian’s Chandra X-
ray Center controls science and flight operations from
Cambridge, Mass. The Space Telescope Science Institute is
operated by the Association of Universities for Research in
Astronomy, Inc. (AURA), for NASA, under contract with the
Goddard Space Flight Center, Greenbelt, Md. The Hubble Space
Telescope is a project of international cooperation between
NASA and the European Space Agency (ESA).

Images and additional information about this result are
available at: