Number 296 (Story #1), November 20, 1996 by Phillip F. Schewe and Ben Stein DO NEUTRINOS PUSH PULSARS AROUND? Many pulsars possess a proper motion across the sky, implying that the pulsars get kicked somehow in the act of being born in the violent explosion of a supernova. A new theory holds that these birth velocities might be caused by a non-symmetric shell of neutrinos rushing away from the supernova collapse. (A large fraction of the energy released in a supernova is vested in neutrinos.) According to Gino Segre of the Univ. of Pennsylvania (segre@dept.physics.upenn.edu), an asymmetry in the "neutrinosphere," the surface at which the neutrinos last scattered before emerging from the star, could be caused by neutrino oscillations (the transformation, say, of tau neutrinos into electron neutrinos) under the bias of the star's magnetic field. A 1% anisotropy in the neutrino distribution could result in a "kick velocity" consistent with the measured average pulsar velocity of 450 km/sec. (Alexander Kusenko and Gino Segre, Physical Review Letters, 9 December 1996.)