““More energy is needed to rise a millimetre above a neutron star's surface than to break completely free of Earth's gravity. A pen dropped from a height of one metre would impact with the energy of a ton of TNT (although the intense gravity on a neutron star's surface would actually, of course, squash any such objects instantly). A projectile would need to attain half the speed of light to escape its gravity; conversely, anything that fell freely onto a neutron star from a great height would impact at more than half the speed of light.””
