Gravity Manipulation: Can It Be Done? Research for Hard SF World

[SkepticJ]

This topic is a little "out there" but what are you thoughts on this being possible someday? I'm doing some research for my Hard SF world and don't want to use anything unplausible. If possible any guesses as to if it'd only need power to turn it on, off and change altitude, not to maintain levitation at the desired altitude? What physical mechanism would allow repulsion against gravitational fields? Could gravity be manipulated not only in the negative but create positive gravity "lasers" to tear objects apart or just pull them to you like sci-fi "tractor beams"?

Thanks for the help if you can.

 

[pervect]

I think that gravitry manipulation (artifical gravity ala Star Trek, inertial dampers that allow large acceleration, tractor beams, pressor beams, etc etc etc) is really not plausible. This has not stopped some reasonably good science fiction from being written. I'd suggest concentrating on the story, and not worrying about the fact that the idea isn't really very plausible scientifically.

There are a few plausible ideas that could be called gravity manipulation written by hard-sf authors, though. If one had hyper-dense materials, one could create regions of zero-gravity on Earth by utiliizing the gravity field of a disk of such a hyper-dense material. By hyper-dense, I'm talking about electron degenerate matter. Now, I don't personally think it's very likely that we will be able to create and stabalize electron degenerate matter, but it's on the bare side of physical possibility. Robert Forward is the author of this (see his collection "Indistinguishable from Magic", or the short story "The Singing Diamond"). I think Forward has some other semi-plausible ideas ideas in the area as well, but I don't recall the details any longer.

Gravity also plays an important role in Stephen Baxter's "Xeelee" series of stories. Here gravity manipulaiton is necessary, because the Xelee are fighting foes basically made out of "dark matter", and gravity is the only thing that will affect them. IIRC, the "dark matter" entities win in the end - they constitute the vast majority of the universe, so it was almost a forgone conclusion. Baxter wisely does not attempt to give any details of the Xeelee's gravity manipulation technology, it is simply presented as ultra-high level technology.

 

[Nenad]

Well, looking at you question, I have to ask how much do you know abut gravity. Gravity is the bending of space time. Most Scientists believe that gravity travels as a wave. A disturbance in this space time would cause a ripple in the very fabric causing a gravity wave. The only idea that I would suggest is a mechanism that would explode with such great force that it would cause a large enough gravity wave to stretch out an object. But, considering that a supernova occurring in our galaxy causes a strain of 10^-20m, then it is most likely that a weapon designed to harm somebody would be just an expensive toy. To answer your question, there is no current mechanicsm that opposes gravity that could possibly make you levitate.

Regards,

Nenad

 

[arildno]

You ought to keep in mind that a scientifically sound, but "wild" idea will usually not be a literary "cool" idea.

 

[GENIERE]

With a constant acceleration of 1G a spacecraft would need no artificial gravity. Interstellar voyages to nearby stars would take a reasonable period of time and when the halfway point is reached just thrust in the opposite direction. I’ve given the answer; someone else will have to provide the power source.

 

[Nenad]

GENIERE, you put up a good idea for interstellar travel but I don't see how it would do anything to cause a grevitational shift or wave being produced.

 

[Crosson]

You can make as gravity as strong as you want (up to and including infinite) but gravity can never be repulsive (no anti-gravity, it would have to be something else pulling you).

See, energy of any form counts as mass as far as gravity is concerned. Therefore an imaginary ultra laser would create gravitational fields whether you wanted it to or not.

 

[SkepticJ]

You can make as gravity as strong as you want (up to and including infinite) but gravity can never be repulsive (no anti-gravity, it would have to be something else pulling you).

Gravity can't be repulsive but what about something else? I seem to remember reading about the universe having some kind of force acting against the gravity in the universe. Something about it expanding faster and faster when it should only be going at a constant rate or slowing down. Anti-gravity just means against gravity. Anything that flies is anti-gravity. I'm aware of Einsteinian gravity being caused by a mass warping space-time into a dimple, like a ball of steel being placed on a membrane of thin rubber. Roll another steel ballbearing around inside this "gravity well" and it orbits the center ball. Does the same thing hold true if gravity is caused by graviton particles(or closed strings if Brane Hypothesis is correct)?

 

[Nenad]

No, the same thing would not hold true if gravitons were discovered. General Relativity describes gravity as the process you described above. While on the opposite end of the spectrum, quantum mechanics chooses to describe gravity as an interaction of gravitons. The graviton is a particle, while general relativity describes gravity as a wave interaction, hence the name 'gravity wave'.

Now string theory or super strings are what unites general relativity and quantum mechanics. It is still to be proven but it could be a solution to today’s gravity explanation problems.

Regards,

Nenad

 

[LURCH]

You can make as gravity as strong as you want (up to and including infinite) but gravity can never be repulsive (no anti-gravity, it would have to be something else pulling you).

This is not necessarily true. Under certain conditions an exotic form of energy known as "negative energy" can be created. (I should add that negative energy has never been directly observed, and may be impossible to observe directly.) Creating these conditions in the lab, physicists have observed a phenomenon which matches the predicted properties of negative energy. By these same models, negative energy is predicted to be gravitationally repulsive. This property has never been observed, due to the extreme difficulty in detecting the gravitational influence of very small amounts of mass. However, since the observed properties so closely match those predicted by the mathematical model, it is reasonable to believe that this prediction is also accurate.

 

[GENIERE]

GENIERE, you put up a good idea for interstellar travel but I don't see how it would do anything to cause a grevitational shift or wave being produced.

Actually reading the article (link follows) and previous related articles has convinced me that ZPF may lead to the long sought field unification. If true, gravity may be a manifestation of EM. As such it may indeed be possible to create anti-gravity devices. Also fascinating is the cause of inertia, and the reason electrons, quarks… acquire mass.

The worrisome part is that I can almost understand it, dooming it to failure.

The article is in the California Institute for Physics and Astrophysics archives. Follow this link:

http://www.arxiv.org/abs/gr-qc/0209016


I believe Lurch is referring to ZPF in his post. If so, that force does exist and has been measured, originally by Lamb who demonstrated an energy shift in the hydrogen electron and later by several investigators of the Casimir effect.

 

[SkepticJ]

Actually reading the article (link follows) and previous related articles has convinced me that ZPF may lead to the long sought field unification. If true, gravity may be a manifestation of EM. As such it may indeed be possible to create anti-gravity devices. Also fascinating is the cause of inertia, and the reason electrons, quarks… acquire mass.

The worrisome part is that I can almost understand it, dooming it to failure.

The article is in the California Institute for Physics and Astrophysics archives. Follow this link:

http://www.arxiv.org/abs/gr-qc/0209016


I believe Lurch is referring to ZPF in his post. If so, that force does exist and has been measured, originally by Lamb who demonstrated an energy shift in the hydrogen electron and later by several investigators of the Casimir effect.

Very interesting. This is sort of the problem, we don't know the universe completely. Kind of hard to base a hard SF on something that could easily be wrong. It will date fast. So let's say ZPF turned out to fit the universe nicely. Does its anti gravity need energy input to maintain it or just to turn it on, off and change levitation height? Another thing. It wouldn't have an altitude limit like you see in say Star Wars where the landspeeders can't fly more than a few meters above the ground? In other words one could get to orbit for really really cheap on energy, among other things?

 

[ZapperZ]

Actually reading the article (link follows) and previous related articles has convinced me that ZPF may lead to the long sought field unification. If true, gravity may be a manifestation of EM. As such it may indeed be possible to create anti-gravity devices. Also fascinating is the cause of inertia, and the reason electrons, quarks… acquire mass.

The worrisome part is that I can almost understand it, dooming it to failure.

The article is in the California Institute for Physics and Astrophysics archives. Follow this link:

http://www.arxiv.org/abs/gr-qc/0209016


I believe Lurch is referring to ZPF in his post. If so, that force does exist and has been measured, originally by Lamb who demonstrated an energy shift in the hydrogen electron and later by several investigators of the Casimir effect.

I need to temper the "raging fire" a little bit here. I know this is all about coming up with some plausible scenario for a Si-Fi story, but let's not lose grip on reality completely here, folks.

The paper that is being cited from the e-print arxiv is based entirely on a paper published by Puthoff and company. Now I don't know about any of you, but Puthoff's ideas are not actually accepted or even uncontroversial, to say the least. Some of the stuff he's saying, if true, would mean that the universe must be OPAQUE. That's how much energy he's claiming he can extract out of the vacuum!

I suggest reading a few dessenting voices to this to balance out the perspective here. I do not want anyone not familiar with this particular field of study to go away thinking everything is fine and dandy. They are not!

http://www.aps.org/WN/WN94/wn031194.cfm
http://www.aps.org/WN/WN02/wn081602.cfm
http://www.aps.org/WN/WN02/wn080202.cfm

Zz.

 

[SkepticJ]

I need to temper the "raging fire" a little bit here. I know this is all about coming up with some plausible scenario for a Si-Fi story, but let's not lose grip on reality completely here, folks.

The paper that is being cited from the e-print arxiv is based entirely on a paper published by Puthoff and company. Now I don't know about any of you, but Puthoff's ideas are not actually accepted or even uncontroversial, to say the least. Some of the stuff he's saying, if true, would mean that the universe must be OPAQUE. That's how much energy he's claiming he can extract out of the vacuum!

I suggest reading a few dessenting voices to this to balance out the perspective here. I do not want anyone not familiar with this particular field of study to go away thinking everything is fine and dandy. They are not!

http://www.aps.org/WN/WN94/wn031194.cfm
http://www.aps.org/WN/WN02/wn081602.cfm
http://www.aps.org/WN/WN02/wn080202.cfm

Zz.

From you're links that man is a nut. Uri Geller, Mercury "mind flight", oh man...

 

[SkepticJ]

So who is this Lamb guy and the people who studied the Casimir Effect? Just because the Puthoff guy is crazy doesn't mean everything he based his hypothesis on is bunk.
If gravitation is caused by gravitons(either particles, closed strings...whatever) does this open the door to possible anti grav unlike say with Einsteinian gravitation?

 

[ZapperZ]

So who is this Lamb guy and the people who studied the Casimir Effect? Just because the Puthoff guy is crazy doesn't mean everything he based his hypothesis on is bunk.
If gravitation is caused by gravitons(either particles, closed strings...whatever) does this open the door to possible anti grav unlike say with Einsteinian gravitation?

The Lamb shift and the Casimir effect are NOT "bunk". None of the links I gave indicated that, and none of what I said even remotely infer that.

But as a bumper sticker that I once read said "Dear God, please save me from your believers", it is the people who took these phenomena and decided to make wild extrapolations to it.

Look, there is a very obvious test for you to check for yourself to know if so-and-so claim is valid - find CONSISTENT and REPRODUCIBLE experimental evidence in peer-reviewed journals. It is THAT simple! And if we apply this test, you'll automatically realize why you should not build any kind of understanding that depends on the existence of "gravitons".

Zz.

 

[RoboSapien]

For creating AntiGravity U need to look at the repulsive forces that exist in nature. One is Magnetic North North pole repulsion, Can U guess the other one ?

I will tell U only if U insist.

 

[Mk]

You can make as gravity as strong as you want (up to and including infinite) but gravity can never be repulsive (no anti-gravity, it would have to be something else pulling you).

See, energy of any form counts as mass as far as gravity is concerned. Therefore an imaginary ultra laser would create gravitational fields whether you wanted it to or not.

Of course the theoretical "exotic matter," not just an exotic matter, but the exotic matter, is like negative mass, and repels normal matter. So to say, a hill on the fabric of space time-rubber sheet analogy.

 

[Icebreaker]

For creating AntiGravity U need to look at the repulsive forces that exist in nature. One is Magnetic North North pole repulsion, Can U guess the other one ?

I will tell U only if U insist.

If antigravity did exist, would it violate the conservation of energy?

 

[SkepticJ]

The Lamb shift and the Casimir effect are NOT "bunk". None of the links I gave indicated that, and none of what I said even remotely infer that.

But as a bumper sticker that I once read said "Dear God, please save me from your believers", it is the people who took these phenomena and decided to make wild extrapolations to it.

Look, there is a very obvious test for you to check for yourself to know if so-and-so claim is valid - find CONSISTENT and REPRODUCIBLE experimental evidence in peer-reviewed journals. It is THAT simple! And if we apply this test, you'll automatically realize why you should not build any kind of understanding that depends on the existence of "gravitons".

Zz.

You don't have to get rough and bite my head off. Yes or no, am I remembering correctly about the universe expanding faster and faster. If I'm remembering correctly they said something like negative energy(whatever this is) could be the cause. Sorry I can't remember the magazine. It was Scientific American, Popular Science, something like that... If negative energy fights against gravity it stands to reason maybe anti-gravity could work.

 

[pervect]

If you somehow had "solid lumps" of exotic matter, they would fall down, just like ordinary matter. The reason is the equivalence principle - with a negative gravitational mass, exotic matter would also have a negative inertial mass. Thus exotic matter would be repelled by the Earth's gravitational field, and hence fall towards the Earth.

But not all is lost. While you couldn't make anything actually "fall up", if you could safely handle exotic matter, you could make a heavy object lighter (lower mass) by adding exotic matter to it, to reduce the total mass of your spaceship/plane/whatever.

By putting together two large masses , one of exotic matter, and one of normal matter, you can even build something that would accelerate indefinitely. There will be a repulsive gravitational force between the two masses - but the normal matter will move in the direction of the force, while the exotic matter will move away from the force. If the two masses are EXACTLY equal, they will maintain a constant separation, and accelerate indefinietly. If gravity does not provide enough force, some sort of spring could be used to generate the force, or they could be charged to generate the force. Probably some sort of active triming will be needed to keep the two masses exactly equal - otherwise the separation between masses will not remain constant, and one will "pull away" from the other.

Unfortunately, exotic matter if it existed in bulk form would probably not be able to be handled safely. One of the other interesting features it would have would be a negative temperature. This means that if one had a lump of exotic matter that acted thermally with normal matter, one would have a run-away heat transfer. The kinetic energy of the exotic matter due to molecular motion (assuming it has molecules or something roughly equivalent, since we are assuming it occurs in a "lump") would become more and more negative. The kinetic energy of the normal matter would become more and more positve. The total energy would remain at zero, of course. The result would be fun as long as it lasted, but eventually the negative energy level of the exotic matter would become so high that it would implode any possible sort of container. Then this exotic matter would continue to exchange energy with its surroundings, until eventually it got a high enough velocity to escape the Earth's gravitational field.

This totally bizare behavior is so unphysical that I personally don't think bulk lumps of exotic matter are likely to exist.

 

[ZapperZ]

You don't have to get rough and bite my head off. Yes or no, am I remembering correctly about the universe expanding faster and faster. If I'm remembering correctly they said something like negative energy(whatever this is) could be the cause. Sorry I can't remember the magazine. It was Scientific American, Popular Science, something like that... If negative energy fights against gravity it stands to reason maybe anti-gravity could work.

Too bad that I only read about the expanding universe and dark energy from papers in physics journals (and not Sci Am) and from speakers like Scott Dodelson (google him and see if he's anybody special).

I would suggest you look up the definition of "dark energy" as we know it today, and figure out if this is "negative energy". Next, figure out what is the General Relativity scaling factor, because THIS is the quantity that is "expanding". After you discover the flaw in your understanding there, then see if your assumption of a direct connection between that this so-called dark energy that is causing such expansion, and "anti-gravity" makes any logical sense.

I am still, continously amazed that one can make such wild leap of speculation based on flimsy, even faulty understanding of what one is trying to talk about. I see nothing that "stands to reason" about such endeavor.

Zz.

 

[SkepticJ]

Too bad that I only read about the expanding universe and dark energy from papers in physics journals (and not Sci Am) and from speakers like Scott Dodelson (google him and see if he's anybody special).

I would suggest you look up the definition of "dark energy" as we know it today, and figure out if this is "negative energy". Next, figure out what is the General Relativity scaling factor, because THIS is the quantity that is "expanding". After you discover the flaw in your understanding there, then see if your assumption of a direct connection between that this so-called dark energy that is causing such expansion, and "anti-gravity" makes any logical sense.

I am still, continously amazed that one can make such wild leap of speculation based on flimsy, even faulty understanding of what one is trying to talk about. I see nothing that "stands to reason" about such endeavor.

Zz.

I come here asking for help and all I get strong rudeness. I can't know everything Mr. Smarter Than Thou, that's why I'm asking about what I don't know. Don't worry, I won't be bothering anyone else with my silly questions, jacka$$.[flips the bird and walks out]

 

[RoboSapien]

Antigravity ?

If antigravity did exist, would it violate the conservation of energy?

Or will it form a balance ?

 

[SkepticJ]

If you somehow had "solid lumps" of exotic matter, they would fall down, just like ordinary matter. The reason is the equivalence principle - with a negative gravitational mass, exotic matter would also have a negative inertial mass. Thus exotic matter would be repelled by the Earth's gravitational field, and hence fall towards the Earth.

But not all is lost. While you couldn't make anything actually "fall up", if you could safely handle exotic matter, you could make a heavy object lighter (lower mass) by adding exotic matter to it, to reduce the total mass of your spaceship/plane/whatever.

By putting together two large masses , one of exotic matter, and one of normal matter, you can even build something that would accelerate indefinitely. There will be a repulsive gravitational force between the two masses - but the normal matter will move in the direction of the force, while the exotic matter will move away from the force. If the two masses are EXACTLY equal, they will maintain a constant separation, and accelerate indefinietly. If gravity does not provide enough force, some sort of spring could be used to generate the force, or they could be charged to generate the force. Probably some sort of active triming will be needed to keep the two masses exactly equal - otherwise the separation between masses will not remain constant, and one will "pull away" from the other.

Unfortunately, exotic matter if it existed in bulk form would probably not be able to be handled safely. One of the other interesting features it would have would be a negative temperature. This means that if one had a lump of exotic matter that acted thermally with normal matter, one would have a run-away heat transfer. The kinetic energy of the exotic matter due to molecular motion (assuming it has molecules or something roughly equivalent, since we are assuming it occurs in a "lump") would become more and more negative. The kinetic energy of the normal matter would become more and more positve. The total energy would remain at zero, of course. The result would be fun as long as it lasted, but eventually the negative energy level of the exotic matter would become so high that it would implode any possible sort of container. Then this exotic matter would continue to exchange energy with its surroundings, until eventually it got a high enough velocity to escape the Earth's gravitational field.

This totally bizare behavior is so unphysical that I personally don't think bulk lumps of exotic matter are likely to exist.

Eh, I'm back. I'm sorry for calling you a jacka$$ Z, but why were you so mean?

I've never heard of exotic matter. What is it exactly? Why couldn't it be held in a magnetic bottle to keep it from touching normal matter and exchanging energy? Would this keep the weird event you described from happening? Somebody gave me a link to something, is this what you're talking about?--> http://www.daviddarling.info/encyclopedia/N/negative_mass_propulsion.html

If possible in real life this would be just what I need. The weight of the flying machines/buildings would be exactly equal to the thrust from these devices, so they neither fall nor go into space. Plus it'd make a great engine for spacecraft within a system, and getting to orbit for really cheap on energy. This site does have something that makes my BS meter go off strongly though--> http://www.daviddarling.info/encyclopedia/Z/ZPE.html
ZPE is real, but not even close to this amount, in mainstream science(real science) so far anyway. One problem with these thrusters though, what keeps them from being used to spin a shaft connected to a generator. This would be a free energy machine; they are impossible.

 

[K.J.Healey]

I have a question that might fall into this topic. Unfortunately it sort of requires something that's not specifically realistic.

Assume a large mass vanishes, just vanishes. Does the manifold of spacetime have restorative forces that could oscillate, or evn just revert too quickly and create an area of the appearance of negative mass?

If we look at space as a 3D "sheet" of rubber, or rather let's make ti 2D or 1D for the sake of visualization, and you take a mass off of it quite quickly (almost like plucking) would the deformation overcompensate? Does the fabric of space have a momentum in the super-dimension of gravity?

Do you see what I'm asking? Of course we don't know for sure, but does our mathematics incorporate this in any way?

I ask this because quickly moving masses would have a similar effect of leaving an impression and removing it right after. I know the "effect" of gravity travels at c, bout would the restoration be linear?

the experiment to validate assuming we could remove masses instantly would be to shine light through the mass, and once vanished , measure its bending(from the other side) as a function of time.
Would the indentation go back to planar uniformly?

Any answers/speculation to these questions?

 

[Danger]

Hi, folks;
Think I'll go check out those links. If the guy thinks that Uri Gellar was anything more than a good sleight-of-hand artist, he's for sure nuts. One thing to mention: the expansion of the universe has nothing to do with gravity. It's the space-time itself that's expanding, not the stuff in it. The regions of space that contain the stars and galaxies are moving away from each other uniformly, but the bodies are not separating within them. They remain gravitationally bound. The molecules in a chocolate chip don't move apart just because the chips themselves mutually recede during baking.

 

[pervect]

Eh, I'm back. I'm sorry for calling you a jacka$$ Z, but why were you so mean?

I've never heard of exotic matter. What is it exactly?

You can think of it as matter with a "negative mass" (what we've been talking about) - see for instance the wikipedia entry

http://en.wikipedia.org/wiki/Exotic_matter

Why couldn't it be held in a magnetic bottle to keep it from touching normal matter and exchanging energy? Would this keep the weird event you described from happening? Somebody gave me a link to something, is this what you're talking about?-->


http://www.daviddarling.info/encyclopedia/N/negative_mass_propulsion.html

That's one of the things I was talking about.

If possible in real life this would be just what I need. The weight of the flying machines/buildings would be exactly equal to the thrust from these devices, so they neither fall nor go into space. Plus it'd make a great engine for spacecraft within a system, and getting to orbit for really cheap on energy. This site does have something that makes my BS meter go off strongly though--> http://www.daviddarling.info/encyclopedia/Z/ZPE.html
ZPE is real, but not even close to this amount, in mainstream science(real science) so far anyway. One problem with these thrusters though, what keeps them from being used to spin a shaft connected to a generator. This would be a free energy machine; they are impossible.

Exotic matter (lumps of matter with a negative mass) are at least as speculative as ZPE. I'm just trying to outline some of the undesirable consequences of negative mass. It's basically naturally unstable in its interaction with positive mass. Think about pushing on something that pushes back, and pushes back harder the more you push on it, for instance. That's just the sort of paradoxical stuff I'm talking about. Even for the purposes of writing a story, it's important to think about the qualities of what one would be writing about.

You could in some sense get "free energy" from even a small amount of bulk exotic matter just by letting it interact thermally with normal matter to heat the normal matter up, and (for instance) drive a turbine. That's one of the reasons I don't like it. Note that this doesn't (quite!) violate the actual second law of thermodynamics.

 

[SkepticJ]

You could in some sense get "free energy" from even a small amount of bulk exotic matter just by letting it interact thermally with normal matter to heat the normal matter up, and (for instance) drive a turbine. That's one of the reasons I don't like it. Note that this doesn't (quite!) violate the actual second law of thermodynamics.

Well if it were possible what's not to like? It'd blow fusion out of the water for geting energy, at least in levels low enough to run a city. Not talking about fusion drive 100km long "space ark" power level. How does it not violate the Second Law though?


The article said accelerate. Accelerate means getting faster all the time. Does this mean that the craft could only go faster, not maintain a constant speed? Could the thrust be varied with this kind of thing; that way my atmospheric craft could gain altitude then just hover without going up or down? I've been thinking of how these devices would be mounted to the flying craft. They'd be inside balls that are in spherical containers, kind of like a mouse ball. They can be rolled into any direction around inside by rollers, or maybe electromagnets so that they can point the thrust in any direction. For a truck-like vehicle they'd have these thruster spheres spaced at each corner so the vehicle doesn't tip over. Would these things even produce enough thrust to win against gravity in a planet's gravity well? What kind of thrust levels are we looking at here for a thruster sphere the size of a basket ball? Thrusters in space don't need to push very much at all, Deep Space One comes to mind. DSO wouldn't move any on Earth, unless it was on a magnetic levitation track and in a vacuum chamber.


Would a magnetic bottle contain exotic matter so that freaky event wouldn't happen with the thermal transfer? Do magnetic bottles have to use electromagnets? Permanent magnets if they'd work for a magnetic bottle is what I'd use. I need an arrangement that would let these flying machines, buildings etc. levitate km above the surface of Thebann for millions of years; just blowing around with the wind. They'd be high enough that they wouldn't ever bump into mountain ranges. Flying derelicts maintained from wearing away from sand etc. abrasion by nanites basically. Plants and animals have even speciated to live on these flying "islands", platforms and machines left by the Thebannese when they moved off into space.

 

[pervect]

Re: your magnetic bottle question

There are two main possiblities that I see - either the particles of the exotic matter are charged or uncharged. If they are uncharged, then they won't be affected by a magnetic field.

IF they are charged, the particles will curve when they enter the magnetic field - the "magnetic mirror" effect. But, an accelerating charge will radiate away energy. With normal matter, this means that the matter loses speed. With exotic matter, this means the matter gains speed.

So the magnetic bottle won't contain exotic matter, as near as I can tell, because the exotic matter particles will keep radiating away energy until they have so high a velocity and so much momentum the magnetic field can't contain them anymore. I think the instability problems with negative mass are fundamental. Possibly someone with a better grasp on QFT could say more - I believe tachyons have similar stability issues.

 

[vcc]

actually I have an idea to produce artifical gravity. Fill a container in space full of water, and pump the water whatever direction that someone would intend your "artificial gravity" to be pulling. That would provide quite a natural environment would it not?

Then again, this has nothing to do with the original topic. Just one of those ideas that I come up with every now-and-then.

*edit* after reading the rest of the post about antimatter, and negative mass, I realize how off-topic I am.. for this, I apologize.

 

[SkepticJ]

There are two main possiblities that I see - either the particles of the exotic matter are charged or uncharged. If they are uncharged, then they won't be affected by a magnetic field.

IF they are charged, the particles will curve when they enter the magnetic field - the "magnetic mirror" effect. But, an accelerating charge will radiate away energy. With normal matter, this means that the matter loses speed. With exotic matter, this means the matter gains speed.

So the magnetic bottle won't contain exotic matter, as near as I can tell, because the exotic matter particles will keep radiating away energy until they have so high a velocity and so much momentum the magnetic field can't contain them anymore. I think the instability problems with negative mass are fundamental. Possibly someone with a better grasp on QFT could say more - I believe tachyons have similar stability issues.

That's some weird stuff. Even if it could be contained it still wouldn't support machines in the sky above an Earth sized and massed world would it? Would negative mass thrusters push much more than their own weight?


Since this NM stuff doesn't seem to be working out is there anything else that might work? Some sort of use of the Magnetic, Strong or Weak forces?

 

[pervect]

That's some weird stuff. Even if it could be contained it still wouldn't support machines in the sky above an Earth sized and massed world would it? Would negative mass thrusters push much more than their own weight?


Since this NM stuff doesn't seem to be working out is there anything else that might work? Some sort of use of the Magnetic, Strong or Weak forces?

Negative mass wouldn't directly support a city in the sky, but if there were some way to contain or stabilize it, it could reduce the mass of the structure enough to allow it to "float" due to buoyant forces from the displaced air.

 

[SkepticJ]

Negative mass wouldn't directly support a city in the sky, but if there were some way to contain or stabilize it, it could reduce the mass of the structure enough to allow it to "float" due to buoyant forces from the displaced air.

If that's all then vacuum sphere balloons made from Higgsinium could be used. Speaking of higgsinium, would a few mountain masses of this along with exmohsium(matter I made up; super dense and has negative mass and inertia close to that of higgsinium's positive) get around this? If matter can't touch exotic matter without doing freaky stuff, and magnetic bottles can't hold it, then how in the universe can one contain it? And I though anti-matter was a pain to deal with.

 

[pervect]

That's a cool link!

I'm afraid I really can't see any way to make negative masses act in a stable manner, but it's always possible I might be missing something.

The instability issues have some interesting and perhaps unfortunate implications for wormholes, which by the articles I've seen naturally tend to have one end acquire a negative mass. So negative mass is not only needed to build wormholes, but is a natural consequence of having them around - just put large quantites of matter through a wormhole, and one end should become more massive, the other less massive, up to and including one end acquiring a negative mass. For instace, see the following link.

http://www.sff.net/people/Geoffrey.Landis/wormholes.htp

Wormholes provide one possible way to create astronomical objects of negative mass, according to theoretical calculations by Matt Visser, professor of physics at Washington University in St. Louis, a co-author of the article. A key element of the theory is the finding that, as matter passes through the wormhole, the "entrance" and "exit" mouths of the hole gain and lose mass.

"According to theory, either end of a wormhole can swallow mass, ejecting it out the other end," said Benford. "But a wormhole mouth in a dense region of matter swallows mass faster than its other end, if that end is in a sparse region. Mass emerging from an end curves space-time oppositely. It's as though the end loses mass, finally reducing to zero mass and then to negative. Gravitationally, that negative end looks like a negative mass, maybe even a large, stable one."

Unfortunately I don't see any way for a negative mass wormhole mouth interacting gravitationally with the rest of the galaxy to avoid the stability issues we've already talked about.