Hot-damn… that outta be cool…
All I ever wanted to know about dropping Black Holes/Neutron Stars I learned from Carl Sagan.
(My copy of Cosmos is frozen in liquid nitrogen - so I’ll just paraphrase)
If you drop some-such object with lots of mass and ~nil volume, it will instantly shoot through Earth - punching a hole through the Earth’s crust, and the liquidish-magma too (though that will ‘heal’ itself).
That object will pop out the other side of Earth (in the Indian Ocean if it was dropped in the USA) and would keep plummeting through the earth hundreds of times - it’s movement only slowed by the friction of the earth’s solids and the insignificant attraction of earth’s gravity. Of course, as Earth rotated beneath it, our planet would continually be perforated - at least temporarily - and when things finally settled down - Sun might be orbiting Earth?
Is it just me or is this the coolest hypothetical thread ever?
I needs to get me some neutronium. Mwahahahhahahahaha!
but then it wouldn’t be a hypothetical thread 
And now I weigh 1200 pounds.
Thanks a lot.
I can’t leave that dumb nit statement uncorrected.
Four thirds pi times the cube of the radius equals 5 cc.
I just forgot how to figure the radius of a sphere of a given volume. TBA was entirely correct 1.0606 is, just as he said, a bit over one centimeter. Sorry.
Tris
Shhhhhh. Your getting in the way of my evil plans. Mwahah-ahahah-hahahah-cough cough cough
loses train of thought and stumbles off
Well now since I don’t want anybody to think I already weigh 600 pounds I have to correct my statement too. 
On the new double-mass earth I would weigh 380 pounds. That will still suck though 
I’m already planning a sci-fi story in which a character uses about two dozen cubic centimeters of neutronium, locked in a control field, as a terrorist weapon (“Give me what I want or I instantly bury us all in a kilometer-wide pile of roiling plasma!”).
Or maybe I’ll have him construct a self-contained ball of neutronium, about the size of your fist, with the containment field generator is at the center of the ball. Then he just drops a few hundred of 'em on a planet and watches the carnage…
As I understand it when something gets very dense there’s two effects. Light falls into it, so it is ‘black’ and it’s compressed by its own gravity to a point.
Does anyone know if these happen at the same time? Which makes it a black hole?
A black hole is defined by the first effect. If an object (which we will assume is round) has an escape speed greater than c, the speed of light, it is called a black hole, and no light radiates from it in the normal sense.
However, it’s interesting that there is not such a thing as “black-hole density”. That is, not all black holes will be equally dense. The larger an object, the less dense it has to be in order to be a black hole.
A lot of people will say that black holes possess at their centers singularities of mass, that all the mass is concentrated at a zero-volume point in the center. I don’t know if this what is actually predicted by physics, or if it’s just a simple way of visualizing it. I do know that observing a black hole, though, we can’t tell what its mass distribution is within the event horizon.
I think the answer will depend on how quickly the neutronium is allowed to expand. Switch off the force field quickly: explosion! You’ll probably mostly get high-energy protons, neutrons, electrons (not to mention plenty of neutrinos and photons). I expect they’ll be too widely scattered to form heavier elements. Now that I’m thinking about it, this experiment might be a good approximation of the Big Bang. Call it a Little Bang.
If you slowly let the force field expand, I think Chronos is right that mostly iron will form. But it will need to be slow enough to allow the nucleons find that lowest energy state.
Really, we can only make physical predictions about the region outside the event horizon. Inside the horizon is pure speculation. The simplest speculation is to just analytically extend the Schwartzschild geometry to the inside: That is to say, assume that the equations describing the geometry have the same form inside as outside. If you do this, then you end up with a singularity at the center. It’s probable, though, that quantum effects become significant at some point, so the equations change close to the center. This would mean that the “singularity” would actually have some small, but nonzero, size (the Planck length, perhaps?).
clubs SPOOFE and patents his idea
Dum dee dum dum… What are you all looking at? You want some of this? huh?
So Spoofe and/or Wearia posess a ‘Space-Payloader’ - a device that can mine and carry Neutron Star matter.
Yet firstly, even if you could pull a Space-Payloader up to a neutron star and pry a ‘teaspoonful’ from it - that teaspoonful would obviously have to have enough mass to hold together with gravity - else it’ll explode with all the re-combined trash of the previously annhilated civilization - or even worse - deadly neutrons.
{ In Star Trek - Romulan ships were driven by ‘Black Holes’ (singularities) so I reckon even Steven Hawking has explained how that might be done }
My point is - if you can already manipulate gravity (the weakest force) - with a ‘Space-Payloader’ - you already can wreak havoc by steering less massive, ‘Sun-sized’ stars at eachother. Perhaps your youth would have been spent re-directing asteroids at un-suspecting M-class worlds.
And that can be done today. Just ask Spoofe 