Quote Originally Posted by koshea
technically a black hole with the mass 3 million times that of the sun isnt possible becuase black holes are the absense of matter in the universe, they crush so much mass togeather and destroy it they defy the law of conservation of mass and energy
Completely and utterly wrong. Black holes are NOT an absence of matter, they are the result of the cumulative force of gravity overwhelming all other forces. Ultimately, as the mass of an object increases, the force of gravity becomes stronger than those forces, such as the strong nuclear force, which tend to keep particles of matter separated. Eventually, even the Pauli Exclusion Principle is insufficient to keep mass from collapsing into itself. The mass of the hole itself doesn't impinge on the universe, and cannot be observed directly. What we "see" is merely the event horizon - that region of space surrounding the black hole where the escape velocity exceeds the speed of light, c. How far the event horizon extends beyond the singularity is measured by the Swartzchild radius, which is calculated by r = mG/c², where r is the Swartzchild radius, m is the mass of the black hole, G is the universal gravitational constant, and c is the speed of light in a vacuum.

However, contrary to the OP, the mergence of two supermassive black holes would most likely be a rather dull event. Since all the action occurs within the event horizon, we basically observe nothing. It is believed that most galactic centers harbor supermassive holes >1 million solar masses, but for the most part, these are isolated having long ago swallowed any matter in their vicinity. Large black holes only appear to emit radiation when significant amounts of matter fall into the event horizon, resulting in huge releases of energy, primarily in the x-ray. In the absence of such associated matter, the collision between two black holes is spectacularly unspectacular.