A neutron star has been clocked travelling at more than 1500 kilometres per second. It joins the ranks of other fast moving neutron stars, deepening the puzzle over how these dense stellar corpses are accelerated to such astonishing velocities.
Neutron stars are the city-sized spheres that remain after stars are destroyed in supernova explosions. They are incredibly dense – a teaspoonful of neutron star material would weigh a billion tonnes.
Many neutron stars are now known to travel at speeds of hundreds of kilometres per second, with one shown in 2005 to be moving at 1100 km/s (see Fastest pulsar set to escape the Milky Way). Some others have been estimated as travelling faster than 1500 km/s but with less certain measurements: their speeds were measured in an indirect way, based on observations of their effect on the gaseous medium that they move through.