i would assume that if the gravitational radii of the black holes were to merge, then, at the event horizons, would they not attempt, since we are now past the point of getting out, to approach each other's singularities as well? by this point they are locked into each other's tidal forces. <br /><br />would the opposing tidal forces keep each black hole orbiting the other? would a gravitationally smaller hole be eaten by a gravitationally larger one, then, creating a larger, single hole, as suggested by one of the first posters?<br />------------------------<br /><br />the thing is, in order to cross the event horizon to the singularity, you cross the moment when light and escape velocity are equal. <br /><br />so farther in, whatever is falling in, must be accelerated beyond light speed as it approaches the singularity within, the interior side, of the event horizon --as you must overcome this speed to exit the event horizon, which you cannot. <br /><br />but another black hole could, as such an object, in it's entirety, would possess the quality of beyond light speed ability, thence the ability to escape from ANOTHER black hole's event horizon. this is why i think two holes would asymptotically, simultaneously, approach and escape from each other. subsequently, the actual geometric moment-area of such a canellation would be irresolute.<br />------------------------<br /><br />as a footnote, the mass of such a region of gravity, ie the black hole, would have no properties of any elements, as it would not subscribe to any known substance. it would not be metallic. or gaseous. or anything. it would be a generic state of density having no identity other than mass and gravity --an abstraction.