Pulsars have superdense neutron stars that form out of massive supernovae. They can only be found when their electromagnetic beams point directly to Earth like a nuclear-powered lighthouse. Pulsars have been found to rotate as fast as 1.6 milliseconds, or 38,500 rpm. They pick up the angular momentum of the massive stars that formed them, but they have a fraction of the size. That traces to rotational speed, in much the same way the skaters spin faster when they pull in their arms.
J0002, located about 6,500 light years away in Cassiopeia, is not that fast. However, it does spin at a healthy 8.7 times a second, each time producing a gamma ray burst seen from Earth. Astronomers at Einstein @ Home spotted it in 201
Scientists are not sure why J0002 is moving faster than 99 percent of measured pulsars. One theory is that the collapsing star that formed it had regions of dense matter that pulled the newly formed neutron star like a "gravitational tugboat." Shortly after it formed, the supernova shell outran the pulsar, but the interstellar gas eventually slowed the relatively loose debris. Meanwhile, the pulsar acted like a cannonball, piercing the remnants and escaping them about 5,000 years after the explosion.
Pulsar J0002 will eventually escape our galaxy too. Suffice to say, you would not want to be in the way – such objects are very small, but can weigh twice as much as our sun. And at 2.5 million MPH, it could travel from Earth to the Moon in just six minutes. At a certain point, it could cool to the point that it can no longer be detected – thankfully, thanks to the built-in arrow, we will always know exactly where it's going