Fast-moving debris from a supernova explosion triggered by a stellar collision crashes into gas thrown out earlier, and the shocks cause bright radio emission seen by the VLA. Credit: Bill Saxton, NRAO/AUI/NSF __________________________________________________________________________ Astronomers have found dramatic evidence that a black hole or neutron star spiraled its way into the core of a companion star and caused that companion to explode as a supernova. The astronomers were tipped off by data from the Very Large Array Sky Survey (VLASS), a multi-year project using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA). “Theorists had predicted that this could...