The hero of this Chandra movie is the Vela pulsar, a neutron star that was formed when a massive star collapsed. The Vela pulsar is about 1,000 light-years from Earth, about 12 miles in diameter, and makes a complete rotation in 89 milliseconds, faster than a helicopter rotor.

As the pulsar whips around, it spews out a jet of charged particles that race along the pulsar’s rotation axis at about 70 percent of the speed of light. The new Chandra data, which were obtained from June to September 2010, suggest the pulsar may be slowly wobbling, or precessing, as it spins. The period of the precession, which is analogous to the slow wobble of a spinning top, is estimated to be about 120 days.

“We think the Vela pulsar is like a rotating garden sprinkler — except with the water blasting out at over half the speed of light,” said Martin Durant of the University of Toronto in Canada, who is the first author of the paper describing these results.

One possible cause of precession for a spinning neutron star is it has become slightly distorted and is no longer a perfect sphere. This distortion might be caused by the combined action of the fast rotation and “glitches,” sudden increases of the pulsar’s rotational speed due to the interaction of the superfluid core of the neutron star with its crust.