Astronomers have accidentally discovered the first-known "black hole triple" system, containing a dark void orbited by two stars. The unique configuration of this triad hints that the black hole was not born via a supernova, which blows away what we thought we knew about how these cosmic entities form.
Until now, most discovered black holes — excluding the supermassive variety at the center of most galaxies — exist in binary systems, in which they are orbited by another large object, such as a star, neutron star or a smaller black hole. This is because the invisible space-time voids are easier to spot when they are gravitationally tugging on other objects.
