Very futuristic and esoteric energy sources

Does anyone know any really esoteric energy sources, I don't mean the kind like using oranges to power iphone chargers, I mean serious "impossible" energy sources to harvest.

I don't really know of the validity of Hawking radiation, or cosmic strings, but if they are existent, they would be the kind of esoteric I mean.

Cosmic strings, because if there's a moving string, then we can have it pull Earth via gravity, and in it's wake will be lots and lots (not sure how much) of blue shifted radiation.

Also, in Asimov's book, The Gods Themselves, there's an alternate universe where Plutonium is stable and it can be sent to Earth and the radiation is harvested as energy.

And if my creativity isn't getting the better of me, would it be somehow possible to harvest gravity waves?

And just wondering about black holes, their gravity should in theory accelerate stuff past c if anything falls in.  Since that's impossible, the object should gain mass as it falls, and when it hits the center, about 5 times times as much mass is added to the black hole as was dumped in.  Hawking radiation could be harvested, and we'd get 5 times as much mass as we put in.  Convert 4/5 of it to energy via Einstein reactor, put the rest back in the black hole.  Infinite energy device, no?

I think the most "out there" energy source I've heard of was the idea of a using a black hole as the axis for an enormous generator .. the idea was to "attach" a belt of sorts to (or near) the event horizon such that the spinning motion would drive the belt .. the belt should then be attached to the giant generator in the other end.. sorta like the mechanism by which you propel a bike forward, only there you deliver the energy ...

Harvesting gravity waves sounds a very nice idea. Perhaps we should succeed in detecting them first.  They do carry a significant amount of energy away from certain astronomic objects, but this energy is spread in all directions, so you would need to be close for the energy density to be more than minute (otherwise it's a bit like using starlight as an energy source). The Earth radiates only about 200W of gravity waves due to its orbit around the sun, which would allow about 10^24 years before its orbit decayed. But a pair of neutron stars can radiate 100 times as much power as gravity waves as our Sun does as electromagnetic radiation for the last 1,000,000 years or so before they merge! See wikipedia.  But how on Earth (actually, off the Earth) do you harvest some of this energy?

Slightly less exotic ways to use a black hole as an energy source involve using them to give a mass some kinetic energy and then doing something with that. In nature, the energy is emitted largely as electromagnetic radiation from the heat of the stuff falling in.  I suppose we would theoretically build a collector sphere to gather the radiation as gas swirls into the black hole. [As for "attaching a belt to the event horizon", I am guessing the person who suggested that was not an engineer ].

No I don't think he was .. =) .. I think the idea was to "attach" it to the gravitational pull of the event horizon .. I cannot remember where I came across it .. but it was suggested to be something you could do at the point where all stars have died .. at that time who knows what would be possible.. =) .. Maybe any remaining life has jumped universe from this one to a younger universe..

Oh, they're called gravitational waves!  I tried to wikipedia gravity waves and I got something related to fluid dynamics.  The page helped a lot, but I still think there should be some way of breaking the first law of thermo.

Like if we took 2 gluons and the strong force interacts between them, more glouns appear, and if we put them close together, even more appear, ad infinitum.  I heard from somewhere gluons were the "particle of the strong force" and they they themselves exhibit a strong force.  Is this true?

I think all the things you said about gluons are true. gluons do interact with other gluons with the strong force (which means virtual gluons pass between them). But the force gets weaker the nearer two particles are to each other. "Assymptotic freedom" is weird as it means that if you knock two quarks apart, the force between them gets stronger and stronger as they get further apart, eventually having enough energy to create lots of other particles until a sort of "pass the parcel" effect eventually gives each of the quarks a partner (or two).

What about a false vacuum?  Apparently, there are around 10^100 Joules in every cubic centimeter of space, because the vacuum is like a particle whose spin, mass, charge, etc. cancel out to average at 0 energy.  Is it possible that some time in the future, vacuum energy can be harvested?  Cosmic strings in theory, are made of vacuum energy, and 1.6 km has supposedly more mass than Earth.  So if we could somehow harvest it, it could be an endless energy source, right?

Hmm.

(1) the mass does not increase. More precisely, there is no violation of the conservation of energy. [Admittedly even stating that law in general relativity is  rather involved]

(2) how were you proposing getting the mass out of the black hole, and why should it stay heavier?

2) If Hawking radiation exists, then we just put particle attractors to get the radiation from the black hole.

1) If a black hole is big enough, then once a particle passes the event horizon, it is is still falling after one second, it should be moving faster than light.  Since nothing is faster then light, the object should gain mass m=E/c^2, or something like that.  So if before it hits the event horizon and stops moving, losing its gained mass, the object first ran into the virtual antimatter particles, it would be the increased mass that is radiated out.  When it stops and its mass is back to normal, for every antimatter particle it hit along the way, it should have lost only 1/5 of the mass afterwards.  I'm probably not explaining my ideas very well...

1.  Something falls into black hole, weighs 1 kg.

2.  It can't accelerate past velocity c, so it gains mass instead on kinetic energy

3.  It has gained enough mass to be 100 kg now.

4.  It runs into 1 kg of virtual antimatter particles along the way.

5.  When it hits the event horizon, it has 100 kg, it stops, so the gained mass is lost and it now has 100/101 kg.

6.  1 kg of matter escaped the black hole by Hawking radiation, and 100/101 kg of matter is added to the singularity.  We started with only 1 kg, and almost doubled the resulting mass.

That's how I propose to break the first thermo law.  What exactly is wrong with my reasoning?

What is right with it?

Actually, the bit about the Hawking radiation is correct, except that the radiation (virtually all photons) is so weak as to be useless except for very, very small black holes, which may be impossible to make. So far, we can only be sure that it is possible to make very large black holes (multiples of the mass of our sun). There is a formula that gives the temperature of a black hole, which look like a "black body" due to Hawking radiation. This formula says that the temperature of black holes of normal size (heavier than our sun) is less than 0.0000001 K. Hence the radiation is at radio frequencies and is very weak. [Without doing the calculation, I think this probably means black holes absorb more energy from starlight than they emit as Hawking radiation, so they don't shrink until the stars go out, and then only very slowly]

If you put heavy things together, you don't end up with something heavier. In classical terms, this is because the binding energy compensates for the additional kinetic energy, just like two charged particles which approach each other, which also gain speed and relativistic mass: the electric field has negative energy to balance it out! The details of this must be more complicated in general relativity, but the result is likely to be the same, with the gravitational field having negative energy to balance the kinetic energy the bodies gain falling towards each other. [In fact, if the objects radiate gravitational waves on the way in, they will end up rather lighter than they started, if no other matter or energy gets involved. This really happens in binary neutron star systems].

The 1kg body dropping into the black hole does not gain rest mass, it gains kinetic energy. But the gravitational binding energy to the black hole (which is negative) gets more and more as it gets nearer to it. While proving that the two result in the combined gravitational field getting no stronger from our position at a distance is too technical for me, I am sure a general relativity specialist could prove this.

Experts have told me that from the point of view of the falling body when it crosses the event horizon, things seem quite normal (apart from the tidal forces ripping it to pieces unless the black hole is exceptionally big). From our point of view it seems never to quite get to the event horizon (because of gravitational time dilation), so we certainly cannot wait for it to pass to the other side - it simply never happens from the point of view of an outside observer. As the object gets nearer to the event horizon it gets redshifted until we are getting hardly any energy from it at all, as massively redshifted radio waves (that were originally light). Its speed away from us causes this as well as the gravitational time dilation.

Gravitational negative energy is a strange concept, but I guess it makes sense since gravity is stronger when mass is more concentrated at the center.  So when two objects fall together, the kinetic energy gained is canceled with the negative energy of the gravitational field?  Does this mean potential energy is really the energy of the field?

Also, neither gravitons nor photons have mass.  They don't have charge either.  So why can gravitational waves escape black holes, whereas light cannot?

And the first law of thermodynamics -- why is it called a law?  It is a theorem, conjecture, definition, etc.?  Has it been proven, or do we just accept it as true?  I still think every law has to have some exception, if we look at it from the right perspective.

http://www.concentric.net/~pvb/negmass.html says if a piece of negative mass hits the ground on Earth, that will be enough to rip a hole in the planet directly to the center.  Doesn't that violate the first law?  What if I pushed two negative mass spheres apart?  They'll move towards each other, and when they hit, what happens?

I feel like everything I've been told about physics in the past 2 years has been a supermarine part of an island, and I haven't even known that there was a giant mountain of knowledge under the water, hidden by the arrogance that the only land that exists is above the water.  The iceberg simile is an understatement.

Yes, potential energy is the energy in the field. As it is zero if the objects are infinitely far apart and decreases as the objects approach each other, it is always negative and gets more and more negative as the objects get nearer. This is basically just the same as for a positive charge and a negative charge, where the electric field has the same property.

Gravitational waves do not escape black holes - they are radiated by accelerating masses, such as any object in rotation about another. The gravitational field from a pure black hole is a static field, without any waves. More precisely, the space-time around a black hole is curved and stays that way.

The first law of thermodynamics is an empirical fact, discovered and stated in the middle of the 19th century, when physics was classical. While it is an empirical fact, and can be an axiom of physics, restricted versions of it can be derived from some formulations of quantum mechanics or general relativity (also from classical electrodynamics and Newtonian gravitational theory).

Negative mass is pure fiction, despite being on the Internet , hence I won't comment. Virtual particles may have negative energy, but they exist for such a short time that this is permitted by the uncertainty principle.

I don't know if this is even theoretically feasible, but maybe we could do some bubble nucleation and connect some wormholes to the universes we're making to farm out their energy! Let's hope we don't kill ourselves in the process.

Elroch:  But how do gravitons escape black holes to exert gravity on other stuff?  If I had this giant magnet, and it pulled in everything with a positive charge (assume gravitons are slightly positive charge), there would be an "event horizon" past which, nothing positively charged can escape, including gravity.  Thus, no gravity would be emitted.  However, gravitons are chargeless, so this situation doesn't happen.  Why should it be different with black holes?  They can emit gravity, so gravitons do escape.  Why can't photons?  Both are massless and charge-less.  Other than purpose, what makes a graviton and photon any different?

Strangequark:  (My interpretation of) the false vacuum page on wikipedia says that bubble nucleation would change cosmological constants as the bubble expands, and when it swallows Earth, everything would either be blown up, or "black-hole-ized", and bubbles expand at the speed of light.  If we could put a bubble in another universe, it does look like a good energy source, but how do we get a wormhole?  And how do we make universes?  I've yet to accomplish the first step in baking an apple pie from scratch.

@pawn_slayer666, excellent questions!

If they exist, gravitons are generated by all energy. If you imagine a black hole completely formed, with nothing remaining outside the event horizon, the question would be tough to answer, but I believe that what we "see" is a frozen image of the black hole just before this stage (due to time dilation approaching infinity at the event horizon). This very slow motion movie of the last moments before the black hole forms persist for an infinite length of time from the point of view of a distant observer. As a result there is time for all of the gravitons to come from the matter just before it falls past the event horizon.

Warning - following this reasoning has led me to believe that Hawking radiation never happens from the point of view of a remote observer, as he would never see the black hole after it had fully formed. (Things would be somewhat different for an observer falling into the black hole). This view has been disagreed with by an expert on these matters, but I have not yet been convinced. As a general rule, one would expect the specialist to be right and me to be wrong. But see an FAQ for an account which vindicates my viewpoint at first and then confuses the issue by claiming that despite the falling mass freezing for ever just above the event horizon, it has really crossed. I think there is an error here, assuming there is a single clock for all points in space. My view is that in physics solid statements can only be made about observations, not things that cannot be observed. If the photons (and gravitons) we get from the object are from it before crossing the event horizon, what observation justifies claiming it has crossed the event horizon?

So my answer is all the gravitons come from the mass (and other energy) outside the event horizon.

But just as light from a black hole is red shifted and dimmed, shouldn't gravity as well get weaker, and get "red-shifted", whatever that means for gravity.

Its only the forces emitted from the mass before falling in that reaches us.  Even though from our point of view, nothing ever gets inside the black hole, isn't that just an afterimage, and whatever had fallen in would be well on its way to the singularity, just no longer capable of making its existence known to us?  So why does the gravity of a black hole fail to diminish?  Is it because gravity is already really weak, so it gets weaker significantly slower than electromagnetism, and we simply don't notice the decay of gravity?

Two questions that may be a little off topic:

Are there any speculations on how a singularity would look like on a string scale?  Would the strings be tangled, arrayed, joined, etc.?  And does a singularity have a particle cloud, i.e. if we did the double slit experiment with black holes (assume infinite density, no spinning), would there be a diffraction pattern?

And have you heard of that phrase, "A black hole is when nature divides by zero."?  That's is usually how I think of them -- nature is just a big calculator.  The Planck time is the "dt" of the system, and time flows based on how quickly the universe can calculate the next frame.  However, computers have bugs (too many on my vista), as does nature.  Sometimes, when a star collapses on itself, it gets the stack overflow error, or div 0 error.  So time is essentially paused there as it tries to sort everything out there.  Slowly, it organizes the particles, but there are too many inside the black hole, so it kicks them out, that's Hawking radiation.  Other than that, nothing gets in, nothing gets out.  Nothing out due to gravity, nothing in, because if you tried to jump in, you'd bounce off the wall of photons and gravitons struggling against gravity at the event horizon.  Without doubt wrong, but ... interesting?

In answer to your first question, the things falling into the black hole gain kinetic energy which means that they produce a stronger gravitational field, but this field gets "red-shifted" due to the gravitational time dilation. The net result is that the gravitational field from a distance is the same as one would expect from the original stationary mass. This is different to light, as there is no analogous process making the light source more powerful as it falls into the black hole.

As I mentioned in my previous post, I am not entirely convinced by the view expressed in the FAQ about what the mass is "really" doing "now". The reason is because this is a question that is not related to any measurements. I am happy with having a full knowledge about what we can observe (by light or gravitational influence). This knowledge is as far as I can see all about the slowed down view of the mass as it approaches the event horizon. While we can in special relativity define a global "now" allowing for all delays due to the distances of objects, this seems inappropriate when the delay would be infinite (from our point of view). It also happens to be not possible in general relativity when there are two possible light paths from an object to us, so I view the global "now" as a flawed concept.

Your "off topic" questions get very deep indeed. I'll pass! Except to say there is nothing stopping you falling into a black hole. Remember real-sized black holes radiate weakly compared to a mobile phone, and exert stupendous gravitational force when you get near to them.

"nothing gets out"-Well I'm not too sure about this yet!

An interesting question is whether this strict observation based viewpoint can be used to derive the thermodynamics of black holes. Simplistically, the forming black hole would appear darker and darker as the matter that was forming it seemed to crawl towards the event horizon. But would we want it to end up looking more like a black body with the correct temperature, a la Hawking? I am not sure if there is a way to arrive at this (can't see why at first thought). Maybe it is not necessary, since what we are seeing is never more than a shrinking ball of matter, slowed down by gravitational time dilation.

What of the matter that was already inside the black hole?  When the star collapses, some matter is already inside the event-horizon-to-be.  That should put at least some mass inside the black hole, even from our perspective, for Hawking radiation to happen.  Does time dilation make this matter move backwards in time, or through imaginary time?  I recall an Einstein equation that gave an imaginary answer for time dilation if something were to move faster than light.