Number 137 (Story #2), July 19, 1993 by Phillip F. Schewe and Ben Stein THE X-RAY EMITTING TAIL OF A PULSAR has been observed with the orbiting Rosat telescope. The Rosat scientists believe that the tail is a pulsar-wind nebula---consisting of relativistic particles cast off by the pulsar---which is shaped by the movement of the nearby pulsar PSR1929 + 10 through the interstellar medium with a proper motion of 70 km/sec. The observation of such pulsar tails will be rare, the scientists believe, because the pulsars must be close to our solar system and the tail must point almost directly at us. (Q. Wang et al., Nature, 8 July 1993.)