If you have 2 similar Black Holes (BHs) side by side, there will be a point of null gravity.  This intern creates an imbalance in the stress/surface tensions of the BHs.  Yes, in the end, you should have one of greater mass than the 2 individuals, but could some mass/energy escape from the total system.  (mass of 2 BHs > mass of 1 super BH?) \n\nCould energy/mass escape in the pop?  I've wondered this for many years. I'd tend to say yes, but don't have the time or math background.  It could negate the big bang theory.
126661
An event horizon (EH) is actually a probability density function, that just happens to be spherical in the absence of other bodies influence. If however, other bodies are exerting influence, the event horizon is hybridized like an electronic orbital near a foreign positive charge like another nucleus. \n\nBasically, what I am trying to say is that two BH's near each other would influence each other, so the EH for each would no longer be spherical, and as someone pointed out, the EH's could actually overlap. Even if the two BH's were in a stable binary orbit, the EH could be joined, or even be a completely inclusive convex shell.
568822
black holes happen when stars colapse.  Stars are massive fusion engines.  Their mass alone should make them colapse on themselves due to gravity but the nuclear fusion reactions going on in them where hydrogen atoms are being smashed together and forming helium atoms create huge constant explosive energy forcing the gasses in a star outward.  Eventualy the hydrogen gets used up.  The fuel for the star is gone and the star has nothing to keep it's mass from collapsing on itself.  All the star's gas molecules attract each other toward the center through the force of gravity and finaly all that mass which had taken up the space of thousands of planets is contained in the space of, ooohhhh I don't know a bowling ball.\n\nThat small ball of used up star has a huge density.  Density is mass divided by volume.  For example,  A nerf ball and a small marble may both weigh the same, but the nerf ball has a larger volume so the density is smaller and therefore the nerf ball is softer and if it has a density less than 1g/cc it will float while the marble will sink.\n\nSee when the the mass is in the numerator and the volume is in the denomenator is the volume.  As the volume (denomenator) gets bigger while the mass (in the numerator) stays the same the whole number gets bigger. \n\nThis is what happens in a black hole as it collapses.  It has the same number of gas molecules as it collapses but they get closer together and the volume gets smaller.  Let's say the mass of the star is 1 and watch what happens to the density as you divide it by a smaller and smaller number.\n\n1/10 = .1\n\n1/1 = 1\n \n1/.01 = 10\n\n1/.001 = 100\n\n1/.000 1 = 1000\n\n1/.000 01 = 10 000\n\nSee as the mass stays the same and the volume decreases the density gets bigger.  It quickly approaches infinity.  Math doesn't handle infinity well and we can't predict what happens at this point.  We call a point of infinite density a singularity.  \n\nThis singularity in a black hole has a huge density and huge gravity so nothing can get out, not even light, hence the name BLACK HOLE.  \n\nSo how do we know they're there?  We can see the efects of the black hole on other stars and Stephen Hawkins predicted that the black holes would actualy emit radiation which was detected proving him right and proving black holes.
363703
They have energy, and gravity depends on stress-energy not simply mass. However, the gravitational interaction would be exceedingly week.\n\nThey also polarise the vacuum state and so can scatter via the electrostatic interaction. This again would be a very tiny effect and has never been detected, though proposals for experiments exist - see link.
338767
First of all, since E = mc^2, you cannot have two massive, energyless bodies.  Secondly, by definition, they have a potential energy of \n.. R\n ∫(-GM1M2/R^2)dR, or GM1M2/R\n. 0\nwith respect to each other, so, again, they cannot be energyless.
530108
As you probably already know, you just can't get a black hole without a certain amount of mass.\n\nBut if this is science fiction, and you wanted to just posit that you could make a moon-massed black hole, then for the most part, the moon would act the same.  If you were, say, navigating around a black hole, you wouldn't treat it any differntly from a star of the same mass.  Things only get wonky one you break the event horizon.  But outside of that, your moon hole would just act like a dark moon-massed object.\n\nAs far as Hawking radiation, if I remember correctly, Hawking suggested that it might be possible for mini-black holes to have formed in the beginning of the universe, and they might have masses less than a standard black hole.  And I think he did suggest that the smaller the black hole is, the faster it evaporates due to Hawking radiation.  So it would not be a huge stretch to say that your moon-sized black whole could dissipate quickly.
362238
From far away, a black hole basically acts like a dark star. It could even have planets orbiting it, though they would be very cold.\n\nWhen you get really close to a typical black hole (less than the diameter of a star), or maybe not so close to it, for massive blackholes like those predicted at the centers of galaxy, then things get weird.\n\nIf you got too close to it, the gravity gradient would be very high, so the tidal forces would tear any matter apart. But assuming you could somehow survive those forces, you would be accelerated towards it and eventually collapsed into neutrons and then when the neutrons collapse, who knows. There could be some pile of quarks at the center, or maybe an actual singularity -- there isn't much knowledge about what forces might exist within subatomic particles. A black hole is the universe's most powerful trash-compactor. There really isn't another 'side'. For you, this collapse would happen pretty quickly. From the viewpoint of an outside observer, it would take forever. This is because time is relative and as you approach light-speed, paradoxically, everything would seem to slow down to the guy watching you. That is, until you cross the event horizon (where light can no longer escape), and so he cannot watch you at all ;-).\n\nConcerning earth, a black hole traveling through our solar system would be much more likely to snag earth in its orbit and pull us out of our orbit with the sun than to actually collide with and consume the Earth. Not that this is much better. Without the sun, life can't survive on earth.
574289
there are problems in your theory... first what can be considered FIXED in the universe. nothing is fixed... its a relative term in this situation.  Also an unbreakable string is an impossibility. There is no such situation where something is completely unbreakable. Even the smallest particle can be broken by enough outside force. \n\n I would like to take your idea to a different level. Lets say it was possible to have an unbreakable string.  Send the ends of this string into 2 different black holes.  Visualize 2 black holes connect by a string.  To answer your first question about seeing the string... You would able to see it until it got to the point where the light wouldn't be able to escape the gravitational pull of the black hole... In theory if the string is unbreakable then it will be impervious to heat and pressure... so it wont melt and crush... Eventually the constant pressure on the string would bring the 2 black holes together. Until the combined gravitational pull of both black holes on each other cause a cataclysmic event where the combined speed and pull of the black holes would cause the entire universe to collapse on itself... and everything as we know it would cease to exist
664758
Not possible. The one which contains more mass may be able to leach matter from the smaller one if it is close enough. All of the matter from the smaller one must pass the EVENT HORIZON of the larger one. No two stars ever actually touch, but may rob matter from one of smaller mass.
358611
It is possible that black holes are the catalyst behind the big crunch, which is the end version of the big bang. Once all of the black holes in existence collect enough matter and energy, they could combine gravitationaly to create one massive black hole that simply repeats the big bang over and over.\n\nBlack holes do not reflect anything, so I don't believe the ignition of the sun was caused by a black hole. \nBlack Hole Info:\n1.They represent matter/energy in its purest form. (All matter and energy is coalesced into one single state of energy)\n\n2.They represent the possible end of our universe.(big crunch)\n\n3.They are the single largest gravitational entity theorized to exist.\n\n4.They are one of the few places that prohibit the propagation of light, so no reflection.\n\n5.The laws of nature at a black hole are completely different from anywhere else in the universe.
303369
Black holes aren't holes in the sense that you're thinking of. A black hole is a region of spacetime (it has 3+1 dimensions like everything else) that has an event horizon (a spherical region) that nothing can escape from.\nTaking the rubber sheet analogy (this is 2+1 dimensional, two spatial dimensions, 1 time dimension), suppose there is a spherical mass placed on the stretched sheet. Depending on how massive that mass is, the sheet around the mass will be circularly distorted, creating a potential energy well. You can roll smaller masses by it. If you roll the smaller mass with too little tangent velocity, it will spiral into the larger mass. If you roll it with a great enough tangential velocity, it may change direction, but it will go right through the potential energy well.\nA black hole has a certain region of its potential energy well (the region inside the event horizon) where no velocity you give a particle will be enough to get it back out of the energy well; all particles entering the event horizon will spiral into the singularity at the center. Part of the reason for this is the limit placed on massive particle accelerations of only being able to accelerate up to the speed of light in vacuum. It is interesting to note that outside the event horizon (assuming a non-spinning black hole), gravity behaves classically. Ie., if the Sun were to collapse into a black hole (which it doesn't have the mass to do), the radius of its event horizon would be less than the current radius of the Sun, so the solar system would continue as usual; the gravitational field outside the event horizon is unchanged.\nAlso, a black hole need not be caused by the death of a star. Primordial black holes are hypothesized to be black holes that formed during the chaotic spacetime of the early universe.
303300
Just one doubt about your  theory,how do you know that only one big bang has taken place as you say that a second one is coming up???And tell me how you would accelerate something to the speed of light as the mass would become infinite.\nAnd according to your theory the total energy in the universe will go on increasing.You are stuck in a viscious circle!!!
161900
As per the current observations and information SMBH (super-mass-...-...) reside in the center of galaxies. Most (not all) of the observable galaxies have a SMBH. There is still an open question that did galaxies form first & then they harboured a SMBH over time OR did the black holes got created first & they pulled over stuff from around & created the galaxy/galaxies, its like a chicken and the egg problem :)
116228
It is an interesting idea, but for the moment, only an idea. The cosmology behind black holes is pretty sound, and they have been observed now, such as in Cygnus x-1.
425614
You have gotten some great answers up to this point.  I'd like to add yet another one...the pre big bang scenario re string/M theory.\n\nOne spin off of string/M theory is that parallel null universes are feasible.  Brian Greene pictures them as slices of bread in a cosmic, N-dimensional loaf of bread. [See source.]\n\nThese are "null" universes because, as far as we are concerned, from our myopic four dimensional world (the metric, observable universe one answerer talked about), these universes exist only in higher dimensions and cannot be observed in 4D.\n\nAccording to one hypothesis, based on string/M theory, two of these slices of bread collided.  That collision point is called the singularity where the big bang originated.  The energy such a collision could generate is one way to account for all the mass-energy postulated for our own known universe.\n\nOf course, as pointed out by other answerers, time and other physics phenomena in null universes may not exist as we know them in metric space.  Null universes are beyond our ken to understand and explain...now.  But who knows, with people like Hawkings, Witten, and others attacking the cosmos and its mysteries, we might just yet unlock the nature and existence of null universes and our own.\n\nPS:  Not all explosions are chemical explosions requiring air (oxygen) to work.  The atomic bomb, for example, does a really nice explosion by simply splitting atoms.   The sun makes spectacular explosions by fusing (putting them together) atoms.  Bottom line, the big bang is not a chemical explosion requiring oxygen.
221746
Assuming this is possible the end positioned inside the event horizon would be broken down into it's individual atoms and would cease to exist.  However some scientists (me being one of them) think black holes are only one end of a worm hole and that when you reach the event horizon you are expelled out of a white hole into another universe.  Think of a white hole as the polar opposite of a black hole, instead of consuming every thing it expels everything
113134
The defining factor of a black hole is that the escape velocity is higher than the speed of light.  This is a function of density and not total mass.  It's possible to have very small black holes.  They can even have masses smaller than that of an atom.  The LHC at CERN, which is expected to come online in 2007, may be capable of producing such microsingularities.  \n\nAs for our universe being a black hole...  from inside it's certainly not.  But, from "outside", if you can define such a thing, maybe it does appear as such, since light cannot escape out universe.  This assumes, however, that there is an outside from which this can be considered, and there's no proof, and perhaps no way to prove, whether or not there is.
99203
First, you it is better to say that the two black holes have the same mass. in such case (or in other cases also) they will begin to gravitate each other by the power of gravity, because according to Isaac Newton any mass is affected by any other mass in the universe.\nwhen they gravitate each other, they begin to orbit each other in a complex way untill they merge with each other forming a new black hole with an event horizon more then the combined primitive two (according to Stephen Hawking).