Void Where Prohibited

So apparently scientists have discovered a void in space that is considerably larger than any void they would expect (presumably based on statistical models for the distribution of matter throughout the universe?) -- on the scale of "a billion trillion miles" . But is it really a void after all?

A common theme in science fiction is interstellar war. Often, some upstart, newly advanced race will set out to conquer the universe with fearsome weapons of war, rolling over older, more mature races in its path (Kevin Anderson's "Empire of the Sun" series concerns this theme, as does Peter Hamilton's excellent "Night's Dawn" trilogy -- if you consider the souls of deceased human beings possessing the living to be an "upstart race"). Similarly, new races may face ancient perils in the form of leftover "doomsday" technology -- Alastair Reynolds' Revelation Space is a prime example of this, as are a handful of old Star Trek episodes. Under the very reasonable assumption that we are not the first in this universe, then, it becomes very reasonable to assume that, throughout the existence of our universe, many races have existed, and have reached a point in their technological development that they are able to interact with other races. And if you'll allow me to anthropomorphize a bit here, I think we may also assume that belligerence could have erupted, on occasion, among those races. If not, at least the expectation of belligerence could be very real.

Back to the void: if it is indeed a statistical anomaly as the article indicates, then it may be a "man"-made phenomenon. This could be the result of one of at least two (presumably very many, though) root causes. First, that some sort of weapon of destruction on a scale unimaginable by human beings had been unleashed at some point in the past, completely annihilating all matter within a certain, very large region. For example, nanotechnology could be exploited to cause this without any remaining trace if the underlying "nano-intelligence" were pre-programmed to be self-terminating after a certain amount of time and operated in such a manner as to remove all matter in an radially increasing fashion from some central point, yielding an area completely devoid of all matter and energy.

Second, though -- perhaps the expectation of belligerence has caused some large civilization simply to hide itself. I don't think it would be particularly daunting for a sufficiently advanced civilization to accomplish this, either: some sort of sustained field or effect surrounding one's entire interstellar civilization with would cause all electromagnetic energy passing through this barrier to return to its source in such a way as to indicate nothing was contained therein. On vastly smaller scales, we already do this ourselves (stealth technology for flying vehicles, echo-repeating technology underwater, etc.). With hyper-advanced automation and access virtually unlimited construction materials, what's to stop a paranoid race from hiding themselves in a similar manner?

I think this has considerable merit, if we look at it from our own humanistic point of view. Our current approach has been one of (very) limited manned, physical exploration combined with lots of remote sensing (think Hubble). Consider then our own reaction, as a species, if this remote sensing discovered irrefutable proof of other intelligent life "out there" -- would not our own insatiable curiously compel us to somehow establish contact with this race by expending great materiel and effort (think the Space Race on steroids)? Suppose, then, that our alien counterparts developed, a long long time ago in a galaxy far far away, in an analogous manner. If we impute to them the same qualities we humans have, along with a healthy dose of paranoia, the end result might be a race determined to proactively hide itself from the prying eyes and ears of fledgling civilizations. And what could be less interesting to our curious sense of exploration than a vast expanse of nothing?

Maybe our statistical models are wrong. Maybe our assumptions of what constitutes "nothing" are also wrong (we can't detect "dark matter", after all, even though scientists believe the bulk of the universe is composed of it, so what's to say that dark matter isn't exactly what we think it is, and this void is actually quite full?). But maybe this void really is anomalous, and anomalies are always worth inspecting a bit closer -- particularly anomalies on the scale of quintillions of miles.