their masses merge. the gravitational forces become so massive that the matters into his think point called the singularity. black holes start small but as they suck up more and more material in their path they can begin to grow and eventually become super massive black holes like the one at the center of our galaxy the milky way. with the mass and the gravitational pull of four million stars like our sun. so far astronomers have been unable to see the milky way's central super massive black hole directly they inferred its existence from the motion of the stars orbiting around. the event horizon telescope has spent two years gathering signals from the black hole the center of our galaxy the telescope is actually a global network of synchronized radio observatories the coordinated with atomic