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Topic: Thoughts about the Ur-Quan... (Read 36561 times)
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Death 999
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We did. You did. Yes we can. No.
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I know. Read carefully. Nonetheless, if you were to drop it at the surface, it would begin a gradually decaying orbit of the planet, right through the middle. This is because it does not interact very strongly at first.
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thatsteveguy
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Everything addict.
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This story has been done. Read "Earth" by David Brin. It goes into great depth as to what will happen to a black hole that falls into our planet. It's a good book and worth the read.,
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Art
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I really dont think that its feasibly possible, even stretching Sci Fi to its limits, to move a black hole. You cant physically manipulate it, obviously, and the only way you can move it is with an equal or greater mass. I.E, another black hole. It's intriuging, but i prefer more conventional planetary destruction means.
Death Stars will always be the best. =p
Oh, that's not necessarily true; if you're the one who makes the black hole you can set up a medium for it to rotate in that generates a magnetic field that stabilizes its position and allows you to manipulate it. (My rough-and-ready knowledge of physics from hard sf peters out here, but I don't think it's theoretically impossible -- wildly difficult, yes, but not impossible. It's the basis for sf ideas of holding very small black holes in containment chambers so you can harness the Hawking radiation as an energy source. Ironically, some semi-canon sources claim that several of these black hole generators are the means by which the Death Star gets the ridiculously impossible levels of energy it needs to blow planets up -- more energy than is generated by the entire surface of the sun in the same amount of time, people have calculated. Oy.)
But for this particular purpose, just dropping a black hole into a planet in order to cause a long-term disaster, you don't need to manipulate it. The black hole itself is just a mass, and is affected by gravity like any other mass (it has to be; gravity is a two-way force, and it can't pull things if things don't pull it). Make it close to the planet or even on the planet's surface, then just let go of the thing and it'll sink down into the planet by itself.
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Death 999
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We did. You did. Yes we can. No.
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Yeah, too bad there are no unbreakable materials.
So, you can move a black hole around magnetically, as Art said. You can also send objects near it which will attract it gravitationally (repeated slingshots off the same side).
However, you wouldn't be able to harness it as a profitable energy source just by consuming the Hawking radiation, unless you kept dumpng matter in... and then it would be the radiation due to the acceleration and disintegration of the dropped object that would be in question.
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Art
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We still dont know anything about black holes, maybe the energy harnessed could be something like switching a lightbulb on and off extremely fast, the gravity flux moving a piston which moves a turbine to produce the hole kinetic=>electric energy.
We still just do not know enough about black holes to make any real theories on them.
Its sort of like guessing how electricity would work, when writing from the perspective of a 14th century peasant. =p
We're not quite that badly off. We do know quite a lot about how black holes interact with their environment, even if we know very little about what's going on inside of them.
The piston idea doesn't work -- the trick of using gravity to power a perpetual motion machine is a very old idea, but it doesn't work, since gravity sources only change potential energy to kinetic energy; to get energy from them there must be a net energy input. That is, you can get constant energy from water flowing downhill, but only if there's some other mechanism that puts in energy to replace the water uphill again (on Earth, that's the energy of the sun allowing water to evaporate and condense again at higher altitudes). The falling piston requires energy to move it back up to the original position before you can use it again.
But I'm cheating here -- you can't get free energy, but that doesn't mean you can't take advantage of systems where there are large amounts of stored potential energy; a waterwheel isn't a true perpetual motion machine, but it's a great way for us to harness the (for our purposes) limitless energy of the sun. So if you have a giant black hole floating in a cloud of gas, the radiation released by the gas as it spirals in will be a quite potent source of energy (which is why observable real life black holes like Cygnus X-1 glow very brightly). On a smaller if less plausible scale, sf has been written about the concept of naturally occurring miniature black holes formed during the Big Bang (the enormous pressures of inflation compressing bits of matter into black holes that normally wouldn't be large enough to collapse on their own). They're unlikely, but it'd be convenient if they were around, as they might be small enough to be manageable yet still contain enough mass that the decay of such black holes through Hawking radiation would make them viable energy sources. They'd be like big batteries where large amounts of mass/energy had been trapped in a conveniently small space by the forces of Creation and such.
Exotic matter from the Big Bang is fun. One idea I'd like to see for a weapon is deploying cosmic strings over a planet and letting them writhe around and slice the planet to pieces. (Cosmic strings are superdense bodies shaped by the Big Bang such that they stay long and thin rather than collapsing into ordinary atoms. They've become a standard sf trick to explain high-tech mechanisms like wormholes and planetary engineering.)
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Art
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I have a question, if you had a perfect sphere of some type of unbreakable material, perfectly surrounding the black hole, would the sphere possess the same mass as the black hole? If you push the sphere on one side, the gravity attracting the other side of the black hole would counter it and keep it the same place.
You are aware that this and other questions you've had aren't particularly applicable to black holes, right? They'd still work the same way for any other relatively large gravity source (the Earth, the Sun, an enormous lump of cheese...)
Black holes interact with their immediate environment using the same rules of gravity as everything else. What's exotic about a black hole is its density, not its mass and its gravitation -- the cool thing about black holes is that they can be very very massive in a very small space (and that space is so small that our physics equations don't tell us how that much mass acts in that little space, making them "black").
But yes, answering your question, the material doesn't even have to be "unbreakable" (a truly unbreakable material is an impossibility anyway). If you had a sphere of matter whose mass was perfectly balanced around a gravity source, then the sphere would remain stable; no single part of the sphere would break off and begin to fall because the gravitational force acting on it is canceled out from the other side.
This is the principle that makes the concept of a Dyson sphere possible. A Dyson sphere would be an enormous feat of engineering in which some super-advanced race that wanted to maximize its energy efficiency could build an enormous sphere completely surrounding a star, soaking up all the radiation the star produces (as opposed to a planet like Earth that soaks up less than one percent of the energy the Sun produces). In theory if the sphere were perfectly uniform it would remain in a stable "orbit", rotating about the star, indefinitely; in reality even if you could get enough materials to build such a sphere (you'd have to convert everything inside of several gas giants into building materials to do it) it would have to be extremely strong and have constantly active powerful correcting mechanisms to keep random irregularities from causing bits to break off and spiral into the star and collapse the whole thing.
Larry Niven came up with the idea of a slightly more modest project in his Ringworld books, about (surprise surprise) a giant tubular ring that forms an enormous living habitat about the star. Such a world would be more feasible, but it still stretches credibility that it could last very long without constant oversight keeping the ring from slipping too far in one direction or another, losing its balance and breaking apart, half of it falling into the star and the rest flying off. (Larry Niven's imaginary engineers aren't just super-smart, they're darn near infallible.)
Either a Dyson sphere or a Ringworld or some other such ridiculously implausible enormous artificial living space would be a cool idea to see in an SC2 sequel or SC2-like game; imagine coming upon a star system that's completely dark, and as you get closer you see it's a *HUGE* sphere of some metal-like material, with doors opening and shutting... (Yeah, it was on Star Trek, I know. They didn't do that great a job with it, though the effects were super cool.)
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FalconMWC
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Yeah - Well Star trek had flames and fireworks in space - but I get your point..... 
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jabbrwock
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But yes, answering your question, the material doesn't even have to be "unbreakable" (a truly unbreakable material is an impossibility anyway). If you had a sphere of matter whose mass was perfectly balanced around a gravity source, then the sphere would remain stable; no single part of the sphere would break off and begin to fall because the gravitational force acting on it is canceled out from the other side.
Er, no. That's not how that works. A spherical shell around a black hole will exert no net gravitational force on the black hole, no matter where within the shell the black hole is located. This is not, however, a reciprocal relationship - the black hole exerts substantial net force on every individual part of the shell. Only an infinitely rigid substance can be realistically considered a single object when subjected to a gravity source sufficiently intense that simple tidal effects can rip atomic nuclei apart. Up until the shell breaks, however, you are correct - the shell will exert the same, zero, net gravitational effect on the black hole no matter where within ths shell the black hole is located, and the black hole will not perturb the shell until and unless it subjects the shell to sufficient gravitational force to break it.
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Art
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Yeesh, jabbrwock is right and I'm wrong. My apologies. (I'm a history major who reads science fiction, so at least it doesn't reflect on my professionalism.  )
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