COSMIC CLOCKS MISS A TICK

Two newly discovered pulsars appear to be active for short periods of time, challenging the view that these objects are the constant clocks of the Universe. Pulsars are rapidly spinning neutron stars that usually appear to emit radio waves to a steady, constant beat. It’s unknown how these pulsars turn their emissions on and off. “These disappearing pulsars may far outnumber normal pulsars. In fact they may redefine what we think of as normal,” says Victoria Kaspi of McGill University in Canada.