What is the 'singularity' in a black hole?

[JavaProphet]

So, I was thinking about it earlier, and I came up with an idea. What if it was just one massive particle? Why that? If a neutron star just kept collapsing, wouldn't all the neutrons just fuse into one big mega-neutron (perhaps the quarks are bonding, or becoming neutron-star like)? I, by no means, have any idea if that is possible, but I wanted to get your guys' thoughts on it.

[Rakaydos]

So, I was thinking about it earlier, and I came up with an idea. What if it was just one massive particle? Why that? If a neutron star just kept collapsing, wouldn't all the neutrons just fuse into one big mega-neutron (perhaps the quarks are bonding, or becoming neutron-star like)? I, by no means, have any idea if that is possible, but I wanted to get your guys' thoughts on it.

A singularity is a mathematical concept. Dividing by 0 is a singularity, as it simotanously generates an answer of infinity and negative infinity. What happens to mass that is so dence it overcomes it;s own resistance to becoming denser is a singlarity.

However, there's a few theories that present alternatives. For instance, the theory that quarks break down into their compoent strings (in string theory) and become a single string-ball.

[PakledHostage]

For instance, the theory that quarks break down into their compoent strings (in string theory) and become a single string-ball.

My cat has one of those!

[K^2]

Black hole is as single particle from just about any perspective, yes.

Neutron stars aren't just a bunch of neutrons, either. There is still some discussion on what exactly the core of the neutron star is like, but the models that treat it as continuous stuff work better than these that try to treat it entirely as neutron matter. It seems that there are several different phases of matter involved, with neutron matter being just the outer crust.

[Lukaszenko]

But I think the point is that no one really knows. It's where our theories break down, both mathematically and otherwise.

A little layman's background on the topic which you probably already know:

Relativity deals everyday objects all the way up to astronomically large and heavy ones. It deals with gravity. It is very successful in describing how these things behave.

Quantum physics deals with very small things, atomic level and below. It deals with atomic forces and also electromagnetism. It is also very successful in describing how these things behave. However, these two theories have practically nothing to do with each other. Relativity is hard to understand, and Quantum physics...well, you just can't understand it. Somehow unifying these two theories into one theory that encompasses everything is the holy grail of physics, but is so far elusive: The Theory of Everything.

A black hole is a very heavy object (relativity) squeezed into a sub atomically small (quantum physics) space.

The point is that basically, if we know what happens in a black hole, we know everything (or vice versa, whichever comes first).

[ZetaX]

A singularity is a mathematical concept.

While it _also_ is a mathematical one, the general meaning is different: it is when known rules break down (another non-mathematical one: the proposed AI singularity).

Dividing by 0 is a singularity, as it simotanously generates an answer of infinity and negative infinity.

Dividing by zero simply does not provide any answer. Some limits are infinities, and that is what comprises a singularity of a function.

Regardless, the "singularity" would not be that we get both signs; indeed, singularities in complex analysis are what one might informally call "points where the function's value is infinity" (and there is only one infinity in this setup). Even in the real setting it is often convenient to identify +ifinity with -infinity.

[-Velocity-]

Regardless of whether or not they are infinitely small points or some tiny but finite-sized object, I don't believe that singularities even exist from our reference frame; "time stops" on the event horizon due to gravitational time dilation. So the singularity itself, regardless of its true nature, is fundamentally unobservable and maybe even non-existent from our frame of reference. Is there any reference frame at all that exists outside of the singularity where the singularity can actually be observed? Even once you're inside the event horizon, isn't any motion away from the singularity impossible? So you could never perceive or measure anything about the singularity until you reached it.... right?

Anyway... if there is some physical law that keeps it from being an infinitely small point, does that mean that there thus must be a limit on the minimum mass of a black hole? If the singularity is to have a fixed, finite size (and thus not be a singularity), would that mean that the least massive black hole would be one that has an event horizon the same size of the finite-sized, not-singularity?

Edited May 13, 2015 by |Velocity|