That is logical, though since, apparently, no one was looking for stuff like this, an orphaned black hole could be barreling down on us as it has throughout human history, with us oblivious to oncoming oblivion. Again, it is a bit like the risk of asteroid collision: An unpredictable but deterministic disaster. That astronomers do not constantly spot heavily distorted regions with no visible cause suggests events like this one are relatively uncommon. That said, the logic cuts both ways, and some or even most things we take for granted as norms might actually be exceptionally rare and hard to detect phenomena that just happen occur very near us.

I honestly do not expect to ever see any terrestrial black hole threat, simply because of the magnitude of astronomical distance and time scales. I just could not resist the imagery conjured by the spectacle of two galaxies ripping out each others singularity hearts and sending them marauding through the universe. I suppose that means I perpetuated the problem with sensationalizing science (sorry. ' />)


*shrugs* If antigravity is plausible gravitational drives are a logical consequence, and it is hard to conceive any kind of recoil not caused by repulsive force. Would balls bounce off the ground if electrons orbiting atoms in each were not both negatively charged? That is what perplexes me: As you note, gravity does not admit such bouncing, because it is exlusively attractive.

What you say makes it sound like Merger Recoil is a misnomer, that singularities do not truly "bounce" off each other any more than they truly "emit" Hawking radiation: They extend gravitational waves, whose direction and intensity fluctuate wildly as they approach, altering their attraction to/of more distant matter. They do not (if I understood you correctly) kick off each other, but matter farther out in (and, theoretically, beyond) their galaxies; that is simply enabled by the singularities proximity affecting its mechanism. Unsurpisingly, that is more plausible than antigravity.

I thought of Hawking Radiation when posting, btw, but unless I badly and fundamentally misunderstand it, even that is not something escaping, but rather entering, an event horizon, preventing recombination with its counterpart. When we get right down to it, and remembering that gravity has an infinite, though weak, range, it is difficult to see galaxies themselves as anything but black holes with expansive accretion disks. Why does the sun not fall into the Milky Ways black hole core? Because it has considerable inertia also, but entropy is imperceptibly yet inexorably wearing on that gyroscope as it does every other, and our sun has no more chance of escaping its black hole than Maximillian did. In a very real sense, Sol does not enter the Milky Ways central singularity because it never left.


My ignorance is not complete, merely non-professional. A little knowledge may be a dangerous thing, but does not equal NONE. Perhaps I oversimplified my suspicions a bit though; all I meant was that

1) The difficulty of unifying gravity with the other fundamental forces, even to the limited degree of reconciling with quantum mechanics,

2) the extent to which the others have been unified and

3) gravitys lack of any polarity

are all highly suggestive of it opposing that force (if any) underlying and unifying all others. I concede a lot of that is my philosophical bias toward the dialectic as "fundamental," but many things would make much more sense if it were true (e.g. a universal singularity "banging" when gravitational attraction was maximal.)