Monster Black Holes May Lurk All Around Us (yahoo.com)

Taco Cowboy quotes a report from Yahoo News: Astronomers have stumbled upon a supermassive black hole in an unexpected corner of the Universe, implying these galactic monsters are much more common than once thought, a study said Wednesday. The giant, with an estimated mass 17 billion times that of our Sun, was discovered in a relative desert, astronomers from the University of California, Berkeley, wrote in the journal Nature. "While finding a gigantic black hole in a massive galaxy in a crowded area of the Universe is to be expected -- like running across a skyscraper in Manhattan -- it seemed less likely they could be found in the Universe's small towns," said a university statement. Big, star-rich galaxies where supermassive black holes had previously been found, are very rare. Smaller ones like the NGC 1600 galaxy housing the newly-discovered whopper, are much more common, but were not previously thought to be appropriate host. "So the question now is: 'Is this the tip of an iceberg?'" said study co-author Chung-Pei Ma. "Maybe there are a lot more monster black holes out there that don't live in a skyscraper in Manhattan, but in a tall building somewhere in the Midwestern plains." The largest supermassive black hole spotted to date tipped the scales at about 21 billion solar masses, said the study authors.

Comments

Black hole in the astronomical desert

[wevets]

Maybe the black hole they found used to be in the center of a super massive galaxy, but had already swallowed up most of the galaxy so there's not much left, leaving the impression that its a super massive black hole in the center of a not-so-massive galaxy?

Re:Black hole in the astronomical desert

[AthanasiusKircher]

As the center of gravity gains mass, formerly stable orbits become unstable and the orbiting bodies fall into the gravity well. This can result in chain reaction which seemingly acts like a giant vacuum cleaner.

One could argue the same thing about a star or even a planet. If enough stuff falls into any astronomical body, its mass could increase and orbits could destabilize.

Black holes are no different in this regard, hence the reason why it's weird to think of them as special kinds of "vacuum cleaners" that are different from other celestial bodies.

Except the proto-planets that did get sucked up in the Sun while our solar system was being formed.

Terms like "sucked up" are the problem. Suction is a specific physical thing created by a vacuum. In that case, the material that is "sucked up" is actually pushed into something else by the fluid pressure difference. It really doesn't make sense to apply this to proto-planets, since they were not pushed into the Sun by some external pressure.

Rather, they did not have sufficient orbital velocity to avoid falling into the gravity well. Using terminology like "vacuum cleaner" or "suction" is a really bad metaphor because it implies all sorts of things that aren't part of the physical scenario in question.

Re:Black hole in the astronomical desert

[slew]

You can gain a whole lot of mass but you're up against the inverse square law. That gravitational 'force' (yes it's really just a geometrical distortion of spacetime) falls away rapidly with distance. The distance is what keeps those remote objects safe.

How can it be "just" a distortion of spacetime and a " 'force' "? There needs to be some actual force to do the distorting of spacetime. You don't get to put quotation marks around "force" and parenthetically claim that gravity is not a force.

The human understanding of the physics behind gravity is not a settled science.

One popular school of thought (called general relativity), that gravity is simply a result of mysterious property of an object called "mass" distorting the fabric of space time so it only appears as a "force" with a field. With this school of thought, you can also think about the strange "force-like" dynamics (e.g, attraction or the change in momentum over time) we observe with gravity fields are really an artifact of our frame of reference (we assume that space-time is not distorted) but in the space-time, really nothing than distorted space time). There is no "force" exhibited by matter that distorts surrounding space-time, but the distortion of space-time is an emergent property of mass (and strangely energy).

However, we know that general relativity is inconsistent with our current understanding of quantum mechanics, so it is probably "wrong", so another school of thought is that analogous to other fields (e.g., electromagnetic fields), the apparently gravitationnal dynamics can be explained by the exchange of particles (or virtual particles) which have been coined as "gravitons". These gravitons would work similarly to how photons mediate the electromagnetic force (and presumably would exhibit wave particle duality like photons).

Of course that often begs the question of what is mysterious mass like property of an object? Some speculate that it is merely parts of an object interacting with a scalar "higgs-field" (it has to be scalar-like, or the "mass-effect" would be different in different directions) caused by an exchange of higgs particles.

How this might all relate back to the first school of thought is called the search for the grand unifying theory. If you figure that one out, a Nobel prize in physics awaits... ;^)