  The observed velocities of radio pulsars, which range in the hundreds
kilometers per second, and many of which exceed 1000 km/s, are not explained by
the standard physics of the supernova explosion. However, if a sterile neutrino
with mass in the 1-20 keV range exists, it would be emitted asymmetrically from
a cooling neutron star, which could give it a sufficient recoil to explain the
pulsar motions. The same particle can be the cosmological dark mater. Future
observations of X-ray telescopes and gravitational wave detectors can confirm
or rule out this explanation.
