No. Because said 'phenomenal & super-massive singularity' itself would be at the center of its own galaxy. And even if it weren't, and collided with another galaxy, it wouldn't just suck the whole galaxy up. The extreme pressures caused by a matter falling into black holes (LOTS of matter trying to get into the same place at the same time) cause the falling material to form an accretion disk (and large jets of matter that get catapulted out into space). If a single giant black hole tried to swallow a whole galaxy, that would make quite a spectacular accretion disk! However, such a large black hole is highly unlikely because it would probably evaporate faster than it could suck in more matter.

And, even if somehow such a massive giant black hole were wandering around without any surrounding matter, it would still be rather hard to miss - it would cause huge-scale gravitational lensing that would be hard to miss.

It is based on many observations - the cosmic background radiation, the earliest quasars, the first mature galaxies, the rate of expansion of the universe today and past rates, collisions in particle accelerators, elemental composition of the known universe. All of these observations were combined together to put together a theory of the evolution of our universe. This theory, combined with astronomical and experimental observations such as the above, were used to calculate an age of roughly 13.7 billion years.

I like that idea. I don't know if it's right, it could be, but it needn't be. I disagree with your idea that the physics of our universe doesn't apply inside black holes. It is blatantly obvious that physics as understood by humans at this time does not apply inside them, but there is one overwhelming piece of evidence that the same physics that applies in our universe must apply to the inside of black holes - there is two-way transfer of information and matter between the inside of black holes and the rest of the universe. People often think of black holes as giant vacuums that suck everything in and keep it there forever but it's not so - black holes actually evaporate! Through the wonders of quantum mechanics, matter is actually able to escape from black holes - it's called Hawking Radiation. If physics didn't apply inside black holes, then two-way transfer of information should be impossible or at least appear nonsensical to us, but that isn't the case.

It doesn't necessarily take energy to move anything from Point A to point B. Objects follow the path of least resistance (in physics-speak, objects follow geodesics - straight lines generalized to curved spacetime). It only takes energy to move an object from A to B if A and B are not successive points on its current geodesic in spacetime. In curved space-time especially, you can't really speak about moving an object between two points in space [time] without also considering the time [space] component because the two are intricately and fundamentally connected. 

No, but we have damn good ideas about a lot of it. Such good ideas that I would actually say we do know a lot of it. Our knowledge isn't exact or complete, but we have a working knowledge about much of the world, its past, its present and its future.

Large black holes are very cold, this will make those actually absorb more energy from cosmic microwave background radiation (CMBR) than they would loose from Hawking-radiation. For small black holes the situation is the reverse. This causes supermassive black holes to be semi-permanent even with no mass to consume (evaporation will occur when the CMBR temperature drops below the temperature of the black hole, it will take a very long time before this process can even begin, hence semi-permanent). Small black holes will evaporate and disappear eventually, the smaller the faster.

None of this has been proven, it is mathematical thories. Hawking-radiation has yet to be observed (for known black holes, the radiation is so weak that CMBR drowns it out) and small black holes exist so far only on paper.

(Everyones favourite place for more info: http://en.wikipedia.org/wiki/Hawking_radiation)

As for the presence of invisible superheavy black holes out in interstellar space: highly improbable, indirect evidence (like described by pigeonpigeon) should be present.

I have a followup question to the OPs. How big is the universe?

Wikipedia has this to say: "The universe is very large and possibly infinite in volume; the observable matter is spread over a space at least 93 billion light years across." (http://en.wikipedia.org/wiki/Universe)

With the observable space, a lower limit is known. But is it possible for the universe to be finite in size if singularities are present? The existance of singularities (black holes), if they are true singularities, should strech space towards infinity but does that mean they contain an infinate volume? From the simplified reasoning below, the answer would be yes, they have an infinite volume, thus their very existance prevents the universe from ever having a finite volume. The math is tricky for me, so I simplify a lot to keep it within my limits which might hurt the outcome, possibly I also draw the wrong conclusions from the result. Anyway, here is the reasoning:

It is assumed that the universe has four dimensions, three spatial and one temporal. Next comes a guess, in order to simplify the problem one spatial dimension can be removed and it is assumed that it can be added back later without significantly changing the result. So the result for the easier three dimensional case is guessed to be comparable to that of four dimensions. The next assumption is that a Gabriel's Horn (the body obtained from rotational volume of the curve y=1/x within the boundries 1 to ∞) can be used to approximate the strech of spacetime where a singularity is present (I do not know how relativity describe singularities). (Math regarding the horn can be found at http://math.ucsb.edu/~cnowlin/Lecture%2020%207-28, example 11.0.5, page 3-7). The Gabriel's Horn suffers from a paradox which makes it have a finite volume but an infinate surface area. If the second assumption (which was a guess) holds true, we can now add another dimension but keep this result. Adding the extra dimension also means that the answers need to be increased with one extra dimension. The former volume becomes a four-dimensional object with a still finite size, while the former surface area become a three-dimensional object (which is interpreted as the real volume) that is still infinate. Space and time are intertwined and not really separable, this causes me to ponder over if the resulting interpretation really is valid. Since the singularity is given a finite four-dimensional solution, it can interact in spacetime with its surrounding and do things like trap matter. But at the same time it contains an infinate volume, most hidden below the event horizon of the singularity, which forces the universe to have an infinate volume.

edit: spelling and phrasing

There are some nice insights there. A couple of your assumptions are incorrect, but not by a whole lot. In many cases you can indeed remove one dimension from a problem and add it back in later. Unfortunately, this is not the case if you're dealing with relativity. Also, even though time and space are inseparable, time is still given special status as a dimension because of its unique properties - and the time dimension can't really add to what we normally call volume, as it isn't spatial. Basically, in this case your removal of time more or less invalidates the conclusions - you calculated the volume of a Gabriel' Horn in flat space-time, when the space near a black hole is as far from flat as you can get. To find the correct result, you would have to perform the same calculation as in that UCSB link, except in curved spacetime - even more complicated, it's a non-uniform curvature. This means that if you look at all the calculations done in that link, you'd have to replace every x and every dx with an extraordinarily complicated and unpleasant mess. That calculation was gross to begin with, and doing so in highly curved, non-uniform spacetime would make me cry - I'm not even sure I could do it.

But my guess is that it wouldn't return an infinite volume. For one, your assumption of adding in time and extrapolating the surface to become a volume and the volume to become 4 dimensional volume doesn't quite work, partially because time is not spatial and partially because it's illegal to do that in relativistic physics (except in special cases, and even then usually not with time) Another reason, though, is that if take a finite space-time and drop a black hole in it, the volume wouldn't change - it would warp and stretch and do all sorts of crazy things, but the effective 'volume' would remain unchanged.

And when i saw the topic i was hoping for a new chapter of "Age of Empire" with futuristic setting

Well... Whatever... for Universe's age i think we need ask to Liara T'Soni x'D

I'm just being facetious. Sometimes I just like to wind people up and watch them spin.

But the fact is that we can only make educated guesses.

You're right... I make educated guesses all the time. It's necessary for survival.

I just can't get my head around the numbers used in astronomy. Seriously, I wonder how capable we are of understanding the sheer size of the universe. Some think the universe is expanding. Into what? And how can we know how big it is if it is expanding?

I should have said "I have no idea." (Or better yet, I should have said nothing  ). When I hear 90 billion light years, it means nothing to me. I can understand 1,000 miles. But I have difficulty with 5.879×10^¹² miles, much less a billion times that amount. The more answers I get, the more questions I have.

Is there a way to report mind raping?

Mumblefratz done went and violated mine

You did'nt see the sarcasm.

The human mind is not evolved to handle such huge numbers. Before around 10,000 years ago, we really had no use for an innate understanding of any number above a couple hundred or so, and so visualising such numbers is very difficult. As far as how capable we are of understanding such large numbers, we just plain are incapable of understanding them. Our mathematics, however, can understand them perfectly and thus acts like a translator for us and at the very least gives us some comparisons with which to put the numbers into perspective. When you say you can understand 1000 miles, I would bet you are imagining the distance on a map, comparing the distance to other known distances, and thus mathematics is providing you with a comparison with which to base your knowledge on. Your understanding is not based on imagining the distance itself. The trick to understanding large numbers is to get a good comparison or set of comparisons with which to judge them.

Well, thats my thought process anyway!

Yes that's true. But it is possible to be able to declare that the Universe is X years old with the same confidence we have when we say, "When I step off of this roof, as long as there is no extreme gust of wind I will fall towards the ground" and "When I jump into this river, I will become wet." Those statements are as definite as possible. But yes you can always go into technicalities; I mean to carry your argument farther there's no definitive way for us to declare that the Earth isn't a giant slug and the Sun isn't just a big flashlight in the sky - but we have extraordinarily good reasons for believing otherwise.

Classical mechanics, quantum physics - THEORIES. And yet they still manage to allow us to build magnetic levitation trains, satellites, lasers, computers. They're all theories, so yes there might be things wrong with them here and there, but they've proven through use that they've gotten plenty of things right. Oh, and Strings really don't belong in your list there - strings have absolutely nothing to do with modern calculations of the age of the universe.

That has nothing to do with whether or not we can determine the age of the universe - it's just another intriguing question whose answer we'd inevitably wind up searching for.

First you say we can't, and then you say "once we do?" Can you say contradiction? And the rest of that sentence makes absolutely no sense. There is no such thing as a "fixed amount of relative years." That is an obvious attempt to sound sophisticated, when really you have no idea what you're talking about - it is a nonsensical combination of words.

First of all, everyone on these forums is ignorant about something (most things, actually). I may be a physicist and knowledgeable about that field and a handful of other things, but I'm ignorant about classical chinese literature, most of neuroscience, taxonomy, and I could keep going on and on. It is perfectly appropriate to call people ignorant when they prattle on about something they really know nothing about as if they do. Having gone to variable levels of school doesn't make you immune to ignorance - for that you need to be god.