Black holes, but backwards: unlocking the mysteries of white holes

Ian Sample meets the Italian physicist Carlo Rovelli to find out
about his cutting-edge research into white holes. A white hole is
essentially a time-reversed black hole: a region of spacetime where
matter spontaneously appears and explodes outwards. At the moment
they are hypothetical objects, so Rovelli explains why he thinks
they are worth exploring and reveals how they could explain one of
the greatest mysteries of physics. Help support our independent
journalism at theguardian.com/sciencepod