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  #1  
Old 07-12-2002, 01:49 PM
Nars Glinley Nars Glinley is offline
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a teaspoon of black hole

It seems that whenever the mainstream news sites have an article that deals with black holes or some other amazingly dense material, they always tell how much a teaspoon of it would weigh. OK, I'm holding a teaspoon out at arm's length and Scotty beams it full of black hole.

What happens next?
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  #2  
Old 07-12-2002, 01:52 PM
Podkayne Podkayne is offline
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First, you'd drop the teaspoon.

I think you're thinking about neutron star, not black holes. You couldn't get a teaspoon-full of black hole--they're stranger critters than that. But a teaspoon-sized black hole would weight about as much as a planet.
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  #3  
Old 07-12-2002, 02:13 PM
Chronos Chronos is offline
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Of course, even with a neutron star, you couldn't get a teaspoonful by itself. Neutronium (the stuff of which neutron stars are made) is stable only under the extreme pressures found in a neutron star. If you tried to isolate a spoonful of it, that spoonful would explosively expand to some more reasonable density, and you'd end up burried under a mountain of (probably) iron.
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  #4  
Old 07-12-2002, 02:57 PM
AndrewL AndrewL is online now
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Unless I'm mistaken, the singularity of the black hole is essentially a one-dimensional object. It's infinitly small - so any size black hole would fit in a teaspoon. The event horizon of the black hole can be much, much larger, and that's what's being referred to when someone speaks of a black hole's size, but that's a mathematical result of the black hole's gravity, not a substance with weight.
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  #5  
Old 07-12-2002, 04:39 PM
kanicbird kanicbird is offline
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Quote:
that spoonful would explosively expand to some more reasonable density, and you'd end up burried under a mountain of (probably) iron
I always wanted to know what would happen if I scooped up a teaspoon of this stuff but mother always said to just let those neutron be, they're just trouble.
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  #6  
Old 07-12-2002, 04:54 PM
The Bad Astronomer The Bad Astronomer is offline
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A cubic centimeter of neutronium is about 10^14 grams = 100 million tons. Don't try this at home. If I figured correctly, that's equavalent to a conical pile of rock 200 meters high by almost 500 meters at the base. Not exactly a mountain, but a fair-sized hill.

As has been pointed out, you can't really have a teaspoon of black hole. I suppose you ould try to mess with the units, such that you have a black hole whose event horizon has the same volume as one teaspoon. A teaspoon is about 5 ccs. A sphere with volume = 5cc has a radius of just over 1 cm.

Interestingly, the mass needed to give you a black hole of one centimeter radius is about 6 x 10^27 grams, which is the mass of the Earth. So, if you squeeze the Earth into a teaspoon, you get a black hole. Kewl.
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  #7  
Old 07-12-2002, 08:11 PM
Nars Glinley Nars Glinley is offline
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OK. Having miraculously survived the neutronium explosion, I whip out my communicator and tell Scotty to try again, only this time, to be sure a put a force field around the teaspoon of neutron star matter. Scotty makes some wiseass comment about me not knowing the difference between a black hole and a neutron star. I make a rebuttal about his drinking problems and we both have a good laugh. He beams another teaspoon of neutronium to me with a properly configured force field.

Now what happens?
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  #8  
Old 07-12-2002, 09:30 PM
kanicbird kanicbird is offline
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NO I want to know waht happens w/o a force field. Will I get a lump of iron or a big hostess ho-ho?
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  #9  
Old 07-12-2002, 11:12 PM
g8rguy g8rguy is offline
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Now you break your wrist trying to hold the teaspoon?
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  #10  
Old 07-12-2002, 11:27 PM
douglips douglips is offline
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This reminds me of neutrinos and black holes in which it turns out that a chunk of neutronium 85 meters thick has the same mass as a chunk of lead 1 light year thick (assuming the other two dimensions are equal, e.g. 85 m x 1 m x 1 m neutronium = 1ly x 1m x 1m Pb)

Imagine the scattering cross-section on that baby!
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  #11  
Old 07-13-2002, 01:29 AM
JonScribe JonScribe is offline
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Wouldn't you rather have a little nondairy creamer with your coffee? It's less fattening than neutronium.
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  #12  
Old 07-13-2002, 01:58 AM
barking frog barking frog is offline
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Quote:
Originally posted by AndrewL
Unless I'm mistaken, the singularity of the black hole is essentially a one-dimensional object. It's infinitly small - so any size black hole would fit in a teaspoon.
I admit I slept through geometry, but if it's infinitely small isn't it zero-dimensional? I thought lines were 1-dimensional.
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  #13  
Old 07-13-2002, 08:23 AM
Joey P Joey P is online now
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It sounds like if someone had a teaspoon of black hole, it would throw the earth out of orbit. Then we'd have to have a law against posession of black hole. ("But officer, I only had a little bit")
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  #14  
Old 07-13-2002, 03:03 PM
AndrewL AndrewL is online now
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Quote:
Originally posted by KRM
OK. Having miraculously survived the neutronium explosion, I whip out my communicator and tell Scotty to try again, only this time, to be sure a put a force field around the teaspoon of neutron star matter. Scotty makes some wiseass comment about me not knowing the difference between a black hole and a neutron star. I make a rebuttal about his drinking problems and we both have a good laugh. He beams another teaspoon of neutronium to me with a properly configured force field.

Now what happens?
Depends on the properties of the force field. To keep the neutronium in it's dense state, we assume it's applying the same force to the sphere that the neutronium was under in its natural location. The first question is - does the force field holding it together also prevent outside matter from interacting with it?

The second question is, what's holding it up? If the force-field is also holding it in place, you've got a solid sphere of neutronium floating in the air near you.


Quote:
Originally posted by k2dave
NO I want to know waht happens w/o a force field. Will I get a lump of iron or a big hostess ho-ho?
I've never tried the experiment, but I'd think that the matter would come out in the form of super-hot plasma and disassociated elementary plasma. Think of it - you have a 100 million tons of matter squeezed into the size of a teaspoon. The only thing holding it stable is the tremendous gravitational pressure it's under. When you remove that gravitational pressure, the matter will rebound outwards with a force equal to the pressure that was holding it in. Boom.
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  #15  
Old 07-13-2002, 03:10 PM
AndrewL AndrewL is online now
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Quote:
Originally posted by KRM
OK. Having miraculously survived the neutronium explosion, I whip out my communicator and tell Scotty to try again, only this time, to be sure a put a force field around the teaspoon of neutron star matter. Scotty makes some wiseass comment about me not knowing the difference between a black hole and a neutron star. I make a rebuttal about his drinking problems and we both have a good laugh. He beams another teaspoon of neutronium to me with a properly configured force field.

Now what happens?
Depends on the properties of the force field. To keep the neutronium in it's dense state, we assume it's applying the same force to the sphere that the neutronium was under in its natural location. The first question is - does the force field holding it together also prevent outside matter from interacting with it? If not, air molecules around it will wander into the force field and be crushed into the surface, addind to the neutronium mass. If the forcefield grows with the mass, the neutronium lump will slowly grow in size as all the nearby air is sucked into it. I suspect that the gravitational force of the lump will be nowhere near great enough to pull nearby objects into it, so it'll just act like a vacume sucking in air. Don't touch it, and you should be safe.

If the force-field contains matter in both directions, nothing in particular will happen. While contained, neutronium won't emit radiation or do anything else particuarily dangerous.

The second question is, what's holding it up? If the force-field is also holding it in place, you've got a solid sphere of neutronium floating in the air near you. If the force-field doesn't support it, the neutronium will fall. Your teaspoon won't even slow it down, nor will the ground under you - normal matter is a thin fog compared to neutronium, trying to hold onto it would be like trying to support a cannonball with a cloudbank. It'll fall right through the earth, crushing or absorbing anything in its path.

Quote:
Originally posted by k2dave
NO I want to know waht happens w/o a force field. Will I get a lump of iron or a big hostess ho-ho?
I've never tried the experiment, but I'd think that the matter would come out in the form of super-hot plasma and disassociated elementary plasma. Think of it - you have a 100 million tons of matter squeezed into the size of a teaspoon. The only thing holding it stable is the tremendous gravitational pressure it's under. When you remove that gravitational pressure, the matter will rebound outwards with a force equal to the pressure that was holding it in. So you really, really don't want to be standing nearby when the force field drops.

(Sorry about the double-post - the board software decided to post the message when I was only half done writing it.)
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  #16  
Old 07-13-2002, 05:20 PM
Chronos Chronos is offline
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I've never tried the experiment, but I'd think that the matter would come out in the form of super-hot plasma and disassociated elementary plasma.
I suspect that very few people indeed have done the experiment. I agree that it'd be some sort of plasma at first, but it's not going to stay that way forever. What do you have when it cools down? My money's on either hydrogen or iron, and I suspect iron.
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  #17  
Old 07-13-2002, 05:33 PM
g8rguy g8rguy is offline
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Why iron, Chronos? I would think you'll get hydrogen at first, but will the density be sufficient to fuse?
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  #18  
Old 07-13-2002, 08:15 PM
Animal Animal is offline
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Yes Ian Fan, a single point in space has no dimension.

Geez, do they really expect us to believe that matter can be condensed into an infinite volume point singularity? How dumb do these scientist think we are?

Infinite volume, hah!
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  #19  
Old 07-13-2002, 08:18 PM
Animal Animal is offline
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Woops, that's infinite density, not infinite volume.

Either way, hah!
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  #20  
Old 07-14-2002, 12:41 AM
Triskadecamus Triskadecamus is offline
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Not to pick a nit, but,

a teaspoon is five cubic centimeters.

The cube root of five is 1.7099

That doesn't round off to one centimeter in diameter. Your black hole is a lot more massive than the earth. Five times as massive, in fact.

Doesn't the prediction of the ratio of Hawking radiation to radius predict that such a black hole would "sublime" into hard gamma radiation rather quickly? Hours, I think I remember, or at the very most within a year.

Tris
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  #21  
Old 07-14-2002, 06:13 AM
SPOOFE SPOOFE is offline
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If the force-field is also holding it in place, you've got a solid sphere of neutronium floating in the air near you. If the force-field doesn't support it, the neutronium will fall. Your teaspoon won't even slow it down, nor will the ground under you - normal matter is a thin fog compared to neutronium, trying to hold onto it would be like trying to support a cannonball with a cloudbank. It'll fall right through the earth, crushing or absorbing anything in its path.
Hot-damn... that outta be cool...
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  #22  
Old 07-14-2002, 06:52 AM
Coriolanus Coriolanus is online now
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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?
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  #23  
Old 07-14-2002, 01:43 PM
Wearia Wearia is offline
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Is it just me or is this the coolest hypothetical thread ever?

I needs to get me some neutronium. Mwahahahhahahahaha!
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  #24  
Old 07-14-2002, 03:38 PM
Qis Qis is offline
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but then it wouldn't be a hypothetical thread
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  #25  
Old 07-14-2002, 03:42 PM
dirty1 dirty1 is offline
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And now I weigh 1200 pounds.

Thanks a lot.
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  #26  
Old 07-15-2002, 12:10 AM
Triskadecamus Triskadecamus is offline
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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
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  #27  
Old 07-15-2002, 01:26 AM
Wearia Wearia is offline
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Quote:
Originally posted by Qis
but then it wouldn't be a hypothetical thread
Shhhhhh. Your getting in the way of my evil plans. Mwahah-ahahah-hahahah-*cough cough cough*

*loses train of thought and stumbles off*
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  #28  
Old 07-15-2002, 02:42 AM
dirty1 dirty1 is offline
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TBA was entirely correct 1.0606 is, just as he said, a bit over one centimeter. Sorry.
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
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  #29  
Old 07-15-2002, 05:50 AM
SPOOFE SPOOFE is offline
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Is it just me or is this the coolest hypothetical thread ever?
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...
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  #30  
Old 07-15-2002, 07:25 AM
Shade Shade is offline
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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?
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  #31  
Old 07-15-2002, 07:35 AM
Achernar Achernar is offline
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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.
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  #32  
Old 07-15-2002, 08:34 AM
Pleonast Pleonast is offline
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Quote:
AndrewL: I've never tried the experiment, but I'd think that the matter would come out in the form of super-hot plasma and disassociated elementary plasma.
Quote:
Chronos: I suspect that very few people indeed have done the experiment. I agree that it'd be some sort of plasma at first, but it's not going to stay that way forever. What do you have when it cools down? My money's on either hydrogen or iron, and I suspect iron.
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.
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  #33  
Old 07-15-2002, 03:44 PM
Chronos Chronos is offline
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Quote:
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.
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?).
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  #34  
Old 07-15-2002, 04:28 PM
Wearia Wearia is offline
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*clubs SPOOFE and patents his idea*

Dum dee dum dum... What are you all looking at? You want some of this? huh?
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  #35  
Old 07-16-2002, 11:54 PM
Coriolanus Coriolanus is online now
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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
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