“N6946-BH1 is the only likely failed supernova that we found in the first seven years of our survey. During this period, six normal supernovae have occurred within the galaxies we’ve been monitoring, suggesting that 10 to 30 percent of massive stars die as failed supernovae.” -Scott Adams
Everyone knows the recipe for a black hole: create a massive enough star, allow it to burn through the fuel it its core, and wait. After enough time, the core will collapse, creating a type II supernova and a runaway fusion reaction. The outer layers explode while the core implodes, leaving behind a black hole if it’s massive enough. Alternatively, merge two failed black holes — i.e., neutron stars — together, and you get a black hole, too.
But there ought to be a third way: through direct collapse. We haven’t seen enough supernovae for the stars that exist, and we don’t have a great explanation, otherwise, for super-early supermassive black holes. For the first time ever, we’ve witnessed a massive star simply wink out of existence. We may have just caught a direct collapse black hole red-handed.