3 ms·With no rest mass. But you can create a black hole by putting enough photons in one place.by knorker 4y agoWith no rest mass. But you can create a black hole by putting enough photons in one place.spixy 4y agoCan I? :)knorker 4y agoYou have my permission. Just as long as it's Not In My Back Yard.kazinator 4y agoThe high density accommodation of matter brought in by a black hole would spoil the character of our neighborhood.