I’m hoping for further information on this topic raised by Chronos here.
Also could this be a way to collect negative mass? Seems like if the black hole is eating virtual particles and emit Hawking radiation, then it should be a 50/50 shot whether it emits positive or negative mass.
Assuming you can somehow contain it without it sinking out of reach into the center of the earth?
You could throw things (literally anything) into it and harness the hawking radiation that comes out. Free mass to energy conversion, hooray!
The Tao’s Revenge - it’s my understanding the negative energy particles always fall into the black hole, which makes everything balance out. I’m not a physicist or anything and, to be honest, I’m not sure I totally understand it so take that with a grain of salt.
I should have added at the end: So far as I’m aware, there’s never a free lunch in anything. Is there any reason to think that the power necessary to create a black hole would be small enough that you would able to get back more energy production within any sort of human time scale (within 100 years say)?
It’s not just Hawking radiation; stuff that gets squeezed as it gets sucked into the hole, stuff that orbits the hole at high speeds as it gets pulled in will put out lots of energy. That’s what you see when you see astronomical pictures of active black holes; Hawking radiation is so tiny with those massive holes that it barely exists. The spectacular effects are all due to the hole’s effect on matter as it falls in.
Basically, as you say if you want energy from a black hole you just have to toss stuff in.
It would depend on the process used. But remember; a hole isn’t limited to the energy you put into it at its creation. You can keep feeding more matter to it and extracting energy from that matter indefinitely.
There are three basic methods. First and most straightforward, there’s the gravitational potential energy. You can get usable energy out of things falling downhill. Well, a black hole is pretty much the ultimate downhill. This method can be used with any black hole whatsoever, and gives you energy equivalent to up to half of the amount of mass you toss in. This process is also what powers quasars, as Der Trihs mentioned.
Second, there’s Hawking radiation. It’s negligible for a large black hole (like, one formed from a star), but for a smaller hole (like one we might hope to form in a laboratory), it can be quite significant. Left to its own devices, a small black hole would evaporate away to nothing, but if you can continually feed it normal matter at the same rate that it’s radiating, you’ve effectively got 100% conversion of matter to energy. Unfortunately, a significant portion of the energy output would be in neutrinos, which we can’t harness, and you’d have to maintain a balancing act to feed the hole just the right amount: Get it too big, and it cools off and doesn’t produce as much radiation any more, and get it too small, and it’ll shrink away out of control and you lose your hole.
Finally, black holes can in principle be magnetic monopoles, and if we have the capability to make them from scratch in a particle accelerator, then we can probably make the monopole kind as well. According to the grand unified theories that combine the strong and electroweak forces, the proton is unstable, and eventually decays into lighter particles. Ordinarily, the proton’s lifetime is exceedingly long (far, far longer than the lifetime of the Universe), but in the presence of a magnetic monopole, the decay should occur much more rapidly. So putting a monopole (including a monopolar black hole) in with normal matter should cause the protons in the matter to decay, effectively converting matter to energy. This method would probably also waste some energy in neutrinos, though how much we can’t say yet without knowing the exact decay process. It might have a greater non-neutrino efficiency than the Hawking radiation process, and you don’t need to worry about ruining your engine: A magnetically-charged black hole would be absolutely stable, unless it meets another one of the opposite charge, so once you get the pair separated they’ll last forever.
Nope.
The particle that falls into the Black Hole has to have negative energy. The rest of the Universe gets the now real particle.
Excerpted from the Alpha Quadrant Institute of Technology (my website, which I just learned is going to shut down when Yahoo deep-sixes Geocities – if you want to download anything from the site, now’s the time). While a work of fiction, I did look into the actual science and tried to be as correct as my feeble mind could muster. Note that references to “evaporation” of a black hole refer to the theory that a black hole loses mass over time due to (very slight) imbalances in the annihilation of virtual matter at the event horizon.
Couldn’t we just make a ridiculously long cable, wind it up on a drum connected to a generator, connect the end of the cable to a mass and throw it in the black hole? Obviously I know the logistics seem a bit off but at least it seems theoretically feasible…
You can also take a spinning kerr-newman black hole and kick some particles through the ergosphere of the hole, and then part of them will come out with more energy than the mass+energy put in.
It’s called the Penrose process. Basically, think of the hole as a giant flywheel (most black holes should be spinning) – you can add or subtract angular momentum from the hole.
As far as using black holes as energy sources, this should be the most efficient method if it works.
Not sure why you’d even need a black hole for this.
Jupiter has a pretty impressive magnetic field.
What’s Jupiter’s magnetic field have to do with anything? What BrandonR is proposing is one possible way to use the gravitational potential energy method. I’m no engineer, so I can’t say if that would be the most practical way to do it, but sure, it would work.
And the Penrose process can only extract that portion of the energy which is stored in the hole’s rotation. Eventually, once you’ve extracted all of the rotational energy the hole started with, you’ve got a non-spinning black hole that can no longer be used for the Penrose process, and no cheap way to spin it back up again. Basically, you’re using the black hole itself as a fuel, rather than the hole enabling you to use some other sort of matter as fuel.
Yes, well, harnessing the freely available angular momentum of a super-stellar sized mass seems a lot more effective, cheap, and efficient way of collecting usable energy than just tossing stuff in like its a campfire, and seems to meet the OP’s lack of criteria just fine.
And hey, when you finally have a schwarschild black hole, then you can just throw things in it if you want.
I guess that depends on whether we get the technology for cheap, deep interstellar travel first, or the technology for laboratory-scale manufactured black holes.
I’m guessing maybe Whack-a-Mole meant to refer to Jupiter’s gravitational field.
Err…yeah. :smack:
Eh, Jupiter’s gravity well isn’t all that useful, since to get down into Jupiter’s well, you first have to get up out of Earth’s well, as well as further up away from the Sun. The surface of the Earth is probably at a lower total gravitational potential than Jupiter. But in any event, none of them are at all even remotely significant compared to the gravity well of a black hole.
A “laboratory sized” black hole will not have significant gravity above the nano-scale event horizon. How would this provide energy?
Is this monopole-induced proton decay a generic feature of all GUTs? Or would it depend on how the forces are unified?