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PowerPedia:Anti-gravity

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Anti-gravity, if attained, would allow means of countering or otherwise modifying the effects of gravity, typically in the context of spacecraft propulsion. Historically, such systems are limited to the realm of science fiction. In spite of the current paradigm of our understanding of gravity, legions of researchers and amateurs have investigated the phenonomena. It is also refered as gravity control and, in slang, as Anti-Grav.

Contents

"Mainstream" gravity and artificial gravity

In physics, gravitation or gravity is the tendency of objects with mass to accelerate toward each other. Gravitation is one of the four fundamental interactions in nature, the other three being the electromagnetic force, the weak nuclear force, and the strong nuclear force. Gravitation is the weakest of these interactions, but acts over great distances and is always attractive. In classical mechanics, gravitation arises out of the force of gravity (which is often used as a synonym for gravitation). In general relativity, gravitation arises out of spacetime being curved by the presence of mass, and is not a force. In quantum gravity theories, either the graviton is the postulated carrier of the gravitational force, or time-space itself is envisioned as discrete in nature, or both.

The gravitational attraction of the Earth endows objects with weight and causes them to fall to the ground when dropped (the earth also moves toward the object, but this is so small the effects are negligible at best). Moreover, gravitation is the reason for the very existence of the earth, the sun and other celestial bodies; without it matter would not have coalesced into these bodies and life as we know it would not exist. Gravitation is also responsible for keeping the earth and the other planets in their orbits around the sun, the moon in its orbit around the earth, for the formation of tides, and for various other natural phenomena that we observe.

Newton's Law of Gravitation considered gravity to be a force between two objects, causing attraction in proportion to the objects' mass. In 1687 Newton published his work on the universal law of gravity in his Mathematical Principles of Natural Philosophy. Newton’s law of gravitation states that: every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

If the particles have masses m1 and m2 are separated by a distance r (from their centers of gravity), the magnitude of this gravitational force is:

F = -G \frac{m_1 m_2}{r^2}

where:

F\, is the magnitude of the (repulsive) gravitational force between the two point masses
G\, is the gravitational constant
m_1\, is the mass of the first point mass
m_2\, is the mass of the second point mass
r\, is the distance between the two point masses

This leads to the equation for gravitational potential energy:

U_g = - {G m_1 m_2 \over r}

This leads to the equation for potential energy. The gravitational potential energy is seen when masses are moved apart (such as when a crate is lifted ), or when masses move together (as when a meteorite falls to Earth). If the masses of the objects are considered point masses, gravitational potential energy is equal to U_g = E_{pG} = - {GmM \over r} where  m\, and  M\, are the two masses in question,  r\, is the distance between them, and G\, is the Gravitational constant.

Under the gravitational force magnitude interpretation, an object with negative mass would repel ordinary matter, and could be used to produce an anti-gravity effect. Alternatively, depending on the mechanism assumed to underlie the gravitational force, it may seem reasonable to postulate a material that shields against gravity or otherwise interferes with the force. An example of such a material, cavorite, is a major element in H. G. Wells' famous book, The First Men in the Moon, although cavorite isn't consistent with even a Newtonian view of the universe (it causes violations of conservation laws). Neither negative-mass exotic matter nor a gravity-screening material have been observed experimentally. While the potential existence of exotic matter is still debated, general relativity presents persuasive arguments against the existence of screening materials.

? Conventional physics unsolved gravity problems
  • Gravity: Is our universe filled with gravitational radiation from the big bang? From astrophysical sources, such as inspiralling neutron stars? What can this tell us about quantum gravity and general relativity? Does gravity behave as predicted at very small distance scales? Why is gravitation so much weaker than other fundamental forces?
  • Quantum gravity: How can the theory of quantum mechanics be merged with the theory of general relativity to produce a so-called "theory of everything"? Is string theory the correct step on the road to quantum gravity, or a blind alley? Is there any way to extract experimental information about the nature of physics at the Planck scale?

Newton's conception and quantification of gravitation held until the beginning of the 20th century, when the German-born physicist Albert Einstein proposed the general theory of relativity. Einstein's theory of general relativity, published in 1915, supplanted Newton's model of gravity with an entirely different mechanism - one based entirely on the geometry of the universe. In this theory Einstein proposed that inertial motion occurs when objects are in free-fall instead of when they are at rest with respect to a massive object such as the Earth (as is the case in classical mechanics). The problem is that in flat spacetimes such as those of classical mechanics and special relativity, there is no way that inertial observers can accelerate with respect to each other, as free-falling bodies can do as they each are accelerated towards the center of a massive object.

To deal with this difficulty, Einstein proposed that spacetime is curved by the presence of matter, and that free-falling objects are following the geodesics of the spacetime. More specifically, Einstein discovered the field equations of general relativity, which relate the presence of matter and the curvature of spacetime. The Einstein field equations are a set of 10 simultaneous, non-linear, differential equations whose solutions are metric tensors of spacetime. These metric tensors describe the squares of the spatial-temporal separations between the coordinates against which the spacetime manifold is being mapped, thereby describing the spacetime itself.

Gravity was no longer a force at all, but simply the consequence of the local slope of the universe in a direction the human eye cannot see: a fourth spatial dimension. Under this model, gravity in a universe containing only matter with positive mass is purely attractive. No arrangement of ordinary matter can produce an anti-gravity effect. Spacetime geometries corresponding to true anti-gravity in general relativity require negative mass. Some models of anti-gravity claim to derive from general relativity.

The model of gravity proposed by the theory of general relativity breaks down under extreme conditions (too far inside a black hole, and in the very early life of the universe under the big bang model). The rapid expansion of the early universe (cosmic inflation) has been verified by the WMAP result, however no satisfactory explanations have been found as of 2006. Galaxy rotation problem is a case where the Spiral galaxy rotation observations do not fit well with traditional gravitation theory. Most physicists believe that at extremely high energies, gravity and the other fundamental forces unify, which would allow gravity to be manipulated in ways that are not readily apparent now. Candidate models for this regime are theories of everything, which attempt to model all four forces (example: string theory), and theories of quantum gravity, which attempt to produce a model of gravity that is consistent with quantum mechanics, though not necessarily unified with the other forces. Some models of anti-gravity claim to be based on quantum gravity models, though the connection of these to mainstream quantum gravity models is often tenuous.

! Alternative theories of gravitation and gravity
  • Aristotelian theory of gravity
  • Le Sage's theory of gravitation (1784) also called LeSage gravity, proposed by Georges-Louis Le Sage, based on a fluid-based explanation where a light gas fills the entire universe.
  • Nikola Tesla announced but never published a Dynamic theory of gravity.
  • Nordström's theory of gravitation (1912, 1913), an early competitor of general relativity.
  • Whitehead's theory of gravitation (1922), another early competitor of general relativity.
  • Brans-Dicke theory of gravity (1961)
  • Induced gravity (1967), a proposal by Andrei Sakharov according to which general relativity might arise from quantum field theories of matter.
  • Rosen bi-metric theory of gravity
  • In the modified Newtonian dynamics (MOND) (1981), Mordehai Milgrom proposes a modification of Newton's Second Law of motion for small accelerations.
  • The new and "highly controversial" Process Physics theory attempts to address gravity
  • The Self creation cosmology theory of gravity (1982) by G.A. Barber in which the Brans-Dicke theory is modified to allow mass creation.
  • Nonsymmetric gravitational theory (NGT) (1994) by John Moffat
  • Tensor-vector-scalar gravity (TeVeS) (2004), a relativistic modification of MOND by Jacob Bekenstein

In some contexts, gravitation is not gravity, per se. Gravitation is a phenomenon independent of any particular cause. Some theorize that it is possible for gravitation to exist without a force; according to general relativity, that is indeed the case. In common usage "gravity" and "gravitation" are either used interchangeably, or the distinction is sometimes made that "gravity" is specifically the attractive force of the earth, while "gravitation" is the general property of mutual attraction between bodies of matter. In technical usage, "gravitation" is the tendency of bodies to accelerate towards one another, and "gravity" is the force that some theories use to explain this acceleration.

Gravity was rather poorly understood until Isaac Newton formulated his law of gravitation in the 17th century. Newton's theory is still widely used for many practical purposes, though for more advanced work it has been supplanted by Einstein's general relativity. While a great deal is now known about the properties of gravity, the ultimate cause of gravitation remains an open question and gravity remains an important topic of scientific research.

"Artificial gravity"

Artificial gravity is a simulation of gravity in outer space or free-fall. Artificial gravity is desirable for long-term space travel for ease of mobility and to avoid the adverse health effects of weightlessness. A craft can rotate so that anything inside will be forced toward the outside by centrifugal force. Artificial gravity by rotation has the following side effects:

  • Coriolis forces produced by rotation could cause dizziness, nausea and disorientation. Experiments have shown that slower rates of rotation reduce the Coriolis forces and its effects. It is generally believed that at 2 rpm or less no adverse effects from the Coriolis forces will occur, at higher rates some people can become accustomed to it and some do not, but at rates above 7rpm few if any can become accustomed. It is not yet known if very long exposures to high levels of Coriolis forces can increase the likelihood of becoming accustomed. The nausea-inducing effects of Coriolis forces can also be mitigated by restraining movement of the head. Head restraints are perhaps practical for exercising in artificial gravity (an artificial gravity gym), but not for much else.
  • Gravity gradients would produce artificial gravity levels that vary proportionately with the distance from the center of rotation. With a small radius of rotation the amount of gravity felt at one's head would be significantly different from the amount felt at one's feet. This could make movement and changing body position awkward.
  • Angular movement facilitated by high angular velocities produced by high levels of Coriolis forces. The angular momentum (the amount of energy to spin) would require a propulsion system of some kind to spin up (or spin down). Also if parts of the spaceship are intentionally not spinning, friction and similar torques will cause the rates of spin to converge (as well as causing the otherwise-stationary parts to spin), requiring motors and power to be used to compensate for the losses due to friction. Angular inertia can also complicate spacecraft propulsion and attitude control.

However, this type of "artificial gravity" is not gravitational in nature, and so is not in the strict sense "gravity".

Artificial gravity and the cancellation of gravity is presented for a useful tool for spacecraft that are neither rotating nor accelerating. At present there is no confirmed technique that can produce gravity other than sheer mass. There have been many claims over the years of such a device. Eugene Podkletnov, a Russian engineer, has claimed since the early 1990s to have made such a device consisting of a spinning superconductor producing a powerful Gravitomagnetic field, but there has been no verification and even negative results from third parties. In 2006 a research group from ESA claimed to have created a similar device that demonstrated positive results for the production of gravitomagnetism, although it produced only 100 millionths of a G.

"Anti-gravity" effects

Tidal forces

Tidal force causes objects to move along diverging paths near a massive body (such as a planet or star), producing effects that seem like repulsion or disruptive forces when observed locally, though this is not "anti-gravity" in the conventional sense. In Newtonian mechanics, the tidal force is the effect of the larger object's gravitational force being different at the differing locations of the diverging bodies. In Einsteinian gravity, the tidal force is the effect of the diverging bodies following different paths in the negatively curved spacetime around the larger body.

The tidal force is a secondary effect of the force of gravity and is responsible for the tides. It arises because the gravitational field is not constant across a body's diameter. When a body (body one) is acted on by the gravity of another body (body two), the field can vary significantly on body one between the side of the body facing body 2 and the side facing away from body two. This causes strains on both bodies and may distort them or even, in extreme cases, break one or the other apart. These strains would not occur if the gravitational field is uniform, since a uniform field only causes the entire body to accelerate together in the same direction and at the same rate.

For a given (externally generated) gravitational field, the tidal acceleration at a point with respect to a body is obtained by vectorially subtracting the gravitational acceleration at the center of the body from the actual gravitational acceleration at the point. Correspondingly, the term tidal force is used to describe the forces due to tidal acceleration. Note that for these purposes the only gravitational field considered is the external one; the gravitational field of the body (as shown in the graphic) is not relevant.

Large amounts of normal matter can be used to produce a gravitational field that compensates for the effects of another gravitational field, though the entire assembly will still be attracted to the source of the larger field. Physicist Robert L. Forward proposed using lumps of degenerate matter to locally compensate for the tidal forces near a neutron star. The accelerating expansion of the universe due to dark energy is an effect that causes a large-scale repulsive force. However, this is not gravitational in nature, and so is in the strict sense not "anti-gravity".

Electrohydrodynamics

Electromagnetic levitation suspends an object against gravity by use of electromagnetic effects. While visually impressive, it is not "true" anti-gravity effects. Critics of various alleged anti-gravity devices, such as the Lifter, often suggest that unusual effects observed around them are due to electromagnetism. Electrokinetics is the science of electrical charges in moving substances, such as water. It studies particle motion which is the direct result of applied electric fields. Electrokinetics covers Electrophoresis, dielectrophoresis, electro-osmosis, and electrorotation. In October 2003, Dr. Daniel Kwok, Dr. Larry Kostiuk and two graduate students from the University of Alberta in researching Water electrokinetics revealed a new method of generating electric power by exploiting the natural electrokinetic properties of a liquid such as ordinary tap water, by pumping fluids through tiny microchannels. This technology could provide a new power source for devices such as mobile phones or calculators which could be charged up by pumping water to high pressure. Kwok explained how, when water travels over a surface, the ions that it is made up of "rub" against the solid, leaving the surface slightly charged. Although the power generated from a single channel is extremely small, millions of parallel channels can be used to increase the power output.

Lifters are an electrokinetic device (or electrohydrodynamic device (EHD)). The term "Lifter" dates back to the 1960s, an era in which EHD experiments were at their peak. In its basic form, it simply consists of two parallel conductive electrodes, one in the form of a fine wire and the other a foil skirt with a smooth round surface, which when powered by high voltage in the range of a few kilovolts, produces thrust. It forms part of the electrohydrodynamic thruster family, but is a special case in which the ionisation and accelerating stages are combined into a single stage. Electrohydrodynamic thrusters are the general and most appropriate term used for high voltage propulsion devices. EHD thrusters, unlike the related ion thruster family, do not need to carry their own gas supply, although they still need to carry their own electrical power source or generator. Also, unlike related propulsion devices, they need the a medium for their operation and cannot operate in a "perfect vacuum". Thankfully, no such state exists in the real world. The interstellar medium (or ISM) is extremely dilute (by terrestrial standards) but exist throughout space. Also, the interplanetary medium density is variable, and may be affected by magnetic fields and events such as coronal mass ejections. It may rise to as high as 100 particles/cm³.

In a geometrical theory of gravitation, the tidal tensor or electrogravitic tensor is one of the pieces in the Bel decomposition of the Riemann tensor. Electrogravitics is physically interpreted as giving the tidal stresses on small bits of a material object (which may also be acted upon by other physical forces), or the tidal accelerations of a small cloud of test particles in a vacuum solution or electrovacuum solution. Electrostatic levitation is the process of using an electric field to lift a charged object and counteract the effects of gravity. It was used, for instance, in Millikan's oil drop experiment and is used to suspend the gyroscopes in Gravity Probe B during launch. Due to Earnshaw's theorem, no static arrangement of classical electrostatic fields can be used to stably levitate an object. There is a point where the two fields cancel, but it is unstable. However, it is possible to use dynamically changing electric fields to hold an object in position. On the moon the photoelectric effect charges fine layers of dust on the surface forming an atmosphere of dust floating in "fountains" over the surface of the moon.

Plasmagnetic levitation is an experimental technology that involves using ultraviolet radiation to turn air into a column of conductive plasma. A current is run through this plasma, and a magnet is used to repel against it, resulting in a form of levitation. HoverTech is currently developing upon this idea, with the hopes of creating a hoverboard-like device. This theory was formerly known as Optomagnetic Suspension, but was redubbed Plasmagnetic Levitation to reflect the importance of plasma to the theorem.

Magnetic levitation, maglev, or magnetic suspension is also often used and is a method by which an object is suspended above another object with no support other than magnetic fields. The electromagnetic force is used to counteract the effects of the gravitational force. A similar effect to gravity has been created through diamagnetism. It requires magnets with incredibly powerful magnetic fields. At present such devices have been made that could levitate at most a small frog, and thus producing a 1 g field to cancel the Earths; yet it required a magnet and system that weighs thousands of kilograms and is kept superconductive with expensive cryogenics and required 6 MW of power. Such extremely strong magnetic fields are far above the permitted levels, and safety for use with humans is at best unclear. In addition, it would involve avoiding any non-diamagnetic materials near the strong magnetic field required for diamagnetism to be evident.

Reactionless drives

The Dean drive or Dean device is a scheme for spacecraft propulsion. The patent is of a variety known as an oscillation thruster. It is named after Norman L. Dean, who called it a reactionless drive and who patented an example of such a device. According to Dean, his propulsion device can produce linear acceleration without the use of any reaction mass. If such a device could be physically realized, it would revolutionize space travel, since in conventional rocketry most of a rocket’s launch weight is devoted to carrying mass that is ejected downwards to drive the remaining mass of the rocket and its payload upwards. A reactionless drive would violate Newtonian physics.

Anti-gravity physics research

A "kinemassic field" generator from U.S. Patent 3,626,605 (G.patent; PDF): Method and apparatus for generating a secondary gravitational force field. The patent is classified as a physics education and demonstraion patent. The device incorporates a refrigeration producer.
A "kinemassic field" generator from U.S. Patent 3,626,605 (G.patent; PDF): Method and apparatus for generating a secondary gravitational force field. The patent is classified as a physics education and demonstraion patent. The device incorporates a refrigeration producer.

The United States government and aerospace contractors publicly announced ambitious Manhattan project-style goals to crack the anti-gravity problem during the mid-1950s while the atomic airplane was on the drawing board, but by the end of 1957 no more information was flowing into the newspapers and magazines. In the world of antigravity research, dynamic counterbary is a term used in the mid-1950's by antigravity researchers at the time to describe the process whereby energy is used to create a local gravitational force independent of the Earth's. A passenger aboard a ship using such a system would have the ability to travel at any speeds in our atmosphere without feeling the slightest force of movement.

According to the aviation trade publication Interavia, solid progress in this area of research, referred to then as "electro-gravitic propulsion," was an established fact by 1956. "In this particular line of research, the weights of some materials have already been cut as much as 30 percent by 'energizing' them. Security prevents disclosure of what precisely is meant by 'energizing' or in which country this work is under way," the magazine reported. "A localized gravitic field used as a ponderamotive force has been created in the laboratory. Disc airfoils two feet in diameter and incorporating a variation of the simple two-plate electrical condenser charged with fifty kilovolts and a total continuous energy input of fifty watts have achieved a speed of seventeen feet per second in a circular air course twenty feet in diameter." The most successful research was said to have been conducted by Thomas Townsend Brown. Brown is known for his early interest in unidentified flying objects (UFOs).

An American scientist, physicist Ning Li, independently predicted a gravity shielding effect with superconductors at nearly the same time as Podkletnov's announcements. In 1999, Li and her team appeared in Popular Mechanics, having constructed a working prototype to generate what she describes as "AC Gravity". The device is known as the high temperature superconducting disc. Li acknowledges that to 'release' the device before knowing that it is indeed functional and not an unexplained aberration could cause a situation similar to the now refuted cold fusion discoveries.[1]

Torr, at the University of South Carolina, commenced work on a most unusual device. According to Charles Platt, Torr describes this device as a "gravity generator" that can create a force beam in any desired direction. Officials of the University of South Carolina, however, apparently disavowed association with this work (in an interview by reporter Charles Platt), and it seems that Torr is seeking private funding to continue his research. James Woodward, an adjuct professor of physics at Cal State in Fullerton, CA, claims to have constructed a device which achieves mass reduction in rather ordinary capacitors.

In November 2005, the United States Patent and Trademark Office (USPTO) granted Boris Volfson, a United States of America inventor, U.S. Patent 6,960,975 (G.patent; PDF) for an anti-gravity device. According to Robert Park, Volfson's device amounts to a perpetual motion machine, defying the theories of physics.[2] [3] [4]. It contains magnets and electromagnets of the superconductive type. The power plant has a reaction motor.

In 2006, Martin Tajmar and several coworkers at the Austrian Research Center (ARC) Seibersdorf announced their claim to have measured the gravitomagnetic London moment of Cooper pairs in a superconducting ring spinning at 6500 rpm. Despite the similarity to the apparatus used by Podkletnov, the authors carefully state in their eprint (see citation below) that their claimed result should not be confused with the claims of Podkletnov.

Heim theory

The Heim theory is a theory of gravitation and particle physics, proposed by Burkhard Heim and further developed by Walter Dröscher and Jochem Häuser. Neither most of their original work nor theories based on it have been peer reviewed. It has been analyzed by a supercomuter and was validated. Heim attempted to resolve incompatibilities between quantum theory and general relativity. To meet that goal, he developed a mathematical approach (using the Selector calculus) based on quantizing spacetime itself, and proposed the "metron" as a (two-dimensional) quantum of (multidimensional) space.

For gravitation, Heim theory assumes that a gravitational potential arises from the gradient of a field φ(r). Position dependent mass is the function m(r), and r is the radial distance from a quanta of a point mass.

A differential equation used to describe the basis is

 \left ( \frac{d \phi}{dr} \right ) ^2 + 32 \frac{c^2}{3}F \left( \frac{d \phi}{dr} + F \phi \right ) = 0, F = \frac{1}{r} \frac{h^2 + \gamma m^3 r}{h^2 - \gamma m^3 r}.

If this equation is nondimensionalized the characteristic length of the system is

r_c = \frac{h^2}{\gamma m^3}.

The characteristic length is the distance from a point mass for which the field φ(r)=0. It is also the case that the field attains its absolute minimum. Hence, the gravitational force is identically zero at this distance.

The solution to the differential equation has the curve φ(r) concave up. The gravitational potential that arises from this field can be positive, negative or zero.

Podkletnov's gravity work

In the 1990s, a Russian emigre scientist Eugene Podkletnov reported gravity shielding with spinning superconductors. Podkletnov claims he saw tobacco smoke rise over the spinning superconductor, so he measured the gravitational acceleration above the device and made the discovery. Podkletnov now claims to have created a force beam that is 200 times stronger than his first experiments.

According to the account Podkletnov gave to reporter Charles Platt in a 1996 phone interview, during a 1992 experiment with a rotating superconducting disk,

Someone in the laboratory was smoking a pipe, and the pipe smoke rose in a column above the superconducting disc. So we placed a ball-shaped magnet above the disc, attached to a balance. The balance behaved strangely. We substituted a nonmagnetic material, silicon, and still the balance was very strange. We found that any object above the disc lost some of its weight, and we found that if we rotated the disc, the effect was increased.

Podkletnov wrote a paper reporting that the gravitational force directly above the disk was about 0.3% less than normal. He concluded that the superconducting disk was altering the earth's gravitational force above it. (Since this initial experiment, Podkletnov claims, he has improved his technique, allegedly obtaining as much as a 2% decrease in the gravitational force.)

In a second interview (1997) by Wired magazine reporter Charles Platt, Podkletnov told Platt that he was continuing to work on gravitation, claiming that with new collaborators at an un-named "chemical research center" in Moscow he has built a new device. He said:

Normally there are two spheres, and a spark jumps between them. Now imagine the spheres are flat surfaces, superconductors, one of them a coil or O-ring. Under specific conditions, applying resonating fields and composite superconducting coatings, we can organize the energy discharge in such a way that it goes through the center of the electrode, accompanied by gravitation phenomena - reflecting gravitational waves that spread through the walls and hit objects on the floors below, knocking them over...The second generation of flying machines will reflect gravity waves and will be small, light, and fast, like UFOs. I have achieved impulse reflection; now the task is to make it work continuously.

More recently, in collaboration with Italian physicist Giovanni Modanese, Podkletnov has reported on a similar device which he claims generates a coherent gravity repulsion beam. (See the citation below.) Supporters claim it has been seen to move a pendulum located 150 meters away in another building. Allegedly, Podkletnov has observed that the "backside" of this second device emits "radiation" (not otherwise specified) which seems to be dangerous to biological tissues.

In his 1997 interview by Charles Platt, Podkletnov insisted that his gravity-shielding work has been reproduced by researchers at universities in Toronto and Sheffield, but none have come forward to acknowledge this. The Sheffield work, for one, is now known to have only been intended as partial replication, aimed at observing any unusual effects which might present themselves, as the team involved lacked access to the necessary facilities for producing a large enough disk and the ability to duplicate the means by which the original disk was rotated. Podkletnov counters that the researchers in question have kept quiet "lest they be criticized by the mainstream scientific community".

Noever's group in Huntsville has allegedly failed to verify Podkletnov's original gravity shielding experiment. Noever suggests this may be due to the extreme difficulty of reproducing a superconducting disk of the size (12 inches/30 cm) used by Podkletnov. Its structure is believed to consist of a metal base, a layer of YBCO, a high critical temperature ("high Tc") superconductor, topped by a layer of YBCO deposited by means of a technique called sputtering. Podkletnov and Modanese suspect that the effect may be linked to the particular surface structure thus created and the interface between the superconducting and non-superconducting layers of the disk.

Rumors wxist that NASA, Boeing, and BAE Systems have funded Podkletnov in reproduction of his experiments (and these have produced varying results). In a BBC news item, it stated that researchers at Boeing have attempted to construct a gravity shielding device, but a subsequent Popular Mechanics news item stated that Boeing had denied this. A "Gravity Research for Advanced Space Propulsion" (GRASP) document contained the following:

  • anti-gravity beam four inches wide had been demonstrated,
  • new weapons system capable of vaporizing objects were possible,
  • a rapidly spinning disc of superconducting material lost up to 2 percent of its weight,and

A Boeing paper stated that "classified activities in gravity modification may exist". According to space.com's business and technology section, Boeing denies 2002 funding at the time of a 2002 article by Nick Cook. They stated:

"We are aware of Podkletnov's work on 'anti-gravity' devices and would be interested in seeing further development work being done. However, Boeing is not funding any activities in this area at this time".

A possible explination of this statement has been suggested: it is alleged that a GRASP proposal was presented to Boeing, but that Boeing chose not to fund GRASP.

Podkletnov told Platt:

..like all Russians, I have a sense of destiny. This is a secret of the Russian soul that can't be explained to foreigners. Even Russian people can't understand it. But - we feel it.

Exotic matter

Exotic matter covers any material which violates one or more classical conditions or is not made of known baryonic particles. Such materials would possess qualities like negative mass or being repelled rather than attracted by gravity. It is used in certain speculative theories, such as on the construction of wormholes. The closest known real representative of exotic matter is a region of pseudo-negative pressure density produced by the Casimir effect. The term is also casually attached to any material which is difficult to produce (such as metallic hydrogen or a Bose-Einstein condensate) or which exhibits unusual properties (such as fullerenes or nanotubes), even though these materials have been created and are relatively well understood. It can also refer to material composed of some form of exotic atom.

Ever since Newton first formulated his theory of gravity, there have been at least three conceptually distinct quantities called mass. However, these three—inertial mass, active gravitational mass, and passive gravitational mass—have so far always been found to be equivalent. When considering hypothetical particles with negative mass, it is important to consider which of these concepts of mass are negative. It can be seen that an object with negative inertial mass would be expected to accelerate in the opposite direction to that in which it was pushed, which is arguably a strange concept, since that would mean that if you pushed such an object, it would run into you. If one were to treat inertial mass, passive gravitational mass, and active gravitational mass distinctly, then objects with negative gravitational mass (both passive and active), but with positive inertial mass, would be expected to be repelled by positive active masses, and attracted to negative active masses. If all such negative matter was like this, then gravity would work similarly to the electric force except that like masses would attract and unlike masses would repel.

Although no particles are known to have negative mass, physicists (primarily Robert L. Forward) have been able to describe some of the anticipated properties such particles may have. Assuming that all three concepts of mass are equivalent would produce a system where negative masses are attracted to positive masses, yet positive masses are repelled away from negative masses. As well, negative masses would produce an attractive force on one another, but would be repelled because of their negative inertial masses. Mmodern researchers suspect that antimatter has positive mass and should fall down just like normal matter. That being said, it is thought that this view has not yet been conclusively empirically observed. It is difficult to directly observe gravitational forces at the particle level. At these small distances, electric forces tend to overwhelm any weak gravitational interaction. Furthermore, antiparticles must be kept separate from their normal counterparts or they will quickly annihilate. Worse still, the methods of production of antimatter typically have very energetic results unsuitable for observations. Understandably, this has made it difficult to directly measure the passive gravitational mass of antimatter. Fortunately, the ATHENA or ATRAP antimatter experiments may soon have the answers.

There are several theories about how antimatter gravitationally interacts with normal matter. Normal gravity with the standard theory asserts that antimatter should fall in exactly the same manner as normal matter. Antigravity in the initial theoretical analysis also focused on whether antimatter might instead repel with the same magnitude. Gravivector and graviscalar theory developed later had difficulties in creating quantum gravity theories and led to the idea that antimatter may react with a slightly different magnitude.

The gravitational interaction of antimatter with matter or antimatter has not been conclusively observed by physicists. While the overwhelming consensus amongst physicists is that antimatter will attract both matter and antimatter at the same rate matter attracts matter, there is a strong desire to confirm this experimentally. If the gravitational interactions between antimatter and matter were found to be repulsive it would be a potential violation of conservation of energy – arguably the most fundamental law of physics.

When antimatter was first discovered in 1932, physicists wondered about how it would react to gravity. Initial analysis focused on whether antimatter should react the same as matter or react oppositely. Several theoretical arguments arose which convinced physicists that antimatter would react exactly the same as normal matter. They inferred that a gravitational repulsion between matter and antimatter was implausible as it would violate CPT invariance, conservation of energy, result in vacuum instability, and result in CP violation. It was also theorized that it would be inconsistent with the results of the Eotvos test of the weak equivalence principle. Many of these early theoretical objections were later overturned. Supporters argue that antimatter antigravity would explain several important physics questions. Besides the already mentioned prediction of CP violation, they argue that it explains two cosmological paradoxes. The first is the apparent local lack of antimatter: by theory antimatter and matter would repel each other gravitationally, forming separate matter and antimatter galaxies. These galaxies would also tend to repel one another, thereby preventing possible collisions and annihilations.

This same galactic repulsion is also endorsed as a potential explanation to the observation of a flatly accelerating universe. If gravity was always attractive, the expansion of the universe might be expected to decelerate and eventually contract into a big crunch. Using redshift observations, astronomers and physicists estimate that instead, the size of the universe is expanding and the rate of expansion is accelerating at an approximately constant rate. Several theories have been proposed to explain this observation within the context of an always-attractive gravity. On the other hand, supporters of antigravity argue that if mutually repulsive, equal amounts of matter and antimatter would precisely offset any attraction.

Gravitoelectromagnetism

Gravitomagnetism (sometimes Gravitoelectromagnetism; abbreviated GEM) refers to a set of formal analogies between Maxwell's field equations and an approximation to the Einstein field equations for general relativity, valid under certain conditions. For instance, the most common version of GEM is valid only far from isolated sources, and for slowly moving test particles. Gravitoelectromagnetism may be valuable to anti-gravity research.

This approximate reformulation of gravitation as described by General Relativity makes a "fictitious force" appear in a frame of reference different from a moving, gravitating body. By analogy, it is called the gravetomagnetic force, since it arises the same way that a moving electric charge creates a magnetic field, which is also a "fictitious force" in Special Relativity. The main consequence of the gravetomagnetic force, or acceleration, is that a free-falling object near a massive rotating object, will begin to rotate.

The effects of such a gravitational field, often loosely referred to as gravitomagnetic effects, are among the last basic predictions of general relativity not yet directly tested. A group at Stanford University is currently analyzing data from the first direct test of GEM, the Gravity B satellite experiment. Frame-dragging is often mentioned as a gravitomagnetic effect, but the Lense-Thirring effect (precession) may be a more appropriate example.

According to general relativity, the gravitational field produced by a rotating object (or any rotating mass-energy) is formally analogous to the magnetic field in classical electromagnetism. Starting from the basic equation of general relativity, the Einstein field equation, and assuming a weak gravitational field or reasonably flat spacetime, Mashhoon, Gronwald, and Lichtenegger, and Clark and Tucker have derived the following gravitational analogs to Maxwell's equations for electromagnetism. They are called the "GEM equations":

 \nabla \cdot E = -4 \pi G \rho
 \nabla \cdot  B = 0
 \nabla \times E = -\frac{1}{c} \frac{\partial B}{\partial t}
 \nabla \times B = \frac{1}{c} \left( -4 \pi G J + \frac{\partial E}{\partial t} \right) = \frac{1}{c} \left( -4 \pi G \rho v {\rho} + \frac{\partial E} {\partial t} \right)

where:

  • E is the static gravitational field (conventional gravity, also called gravitoelectric for the sake of analogy);
  • B is the gravitomagnetic field;
  • ρ is mass density (instead of electric charge density);
  • vρ is the velocity of the mass flow generating the gravitomagnetic field;
  • J is mass current density (J = ρ vρ);
  • G is the gravitational constant;
  • c is the speed of propagation of gravity (according to General Relativity, equal to the speed of light).

For a test particle of small mass m, the net (Lorentz) force acting on it due to GEM fields is described by the following GEM analog to the Lorentz force equation:

 {F}_{m} = m \left( {E} + \frac{{v}_{m}} {c} \times 2 {B} \right) .

where:

  • m is the mass of the test particle;
  • vm is the instantaneous velocity of the test particle;

In the literature, all instances of B in the GEM equations are multiplied by 1/2, a factor absent from Maxwell's equations. This factor is unnecessary if B in the GEM version of the Lorentz force equation is multiplied by 2, as shown above. The factors 2 and 1/2 arise because the effective gravitomagnetic charge is twice the static gravitational (gravitoelectric) charge, a remnant of the spin-2 character of the gravitational field. For a pure spin-1 field such as the genuine electromagnetic field, the magnetic charge equals the electric charge.

The above GEM equations are very similar to Maxwell's equations in free space, expressed using CGS units.

 \nabla \cdot {E} = 4\pi\rho
 \nabla \cdot {B} = 0
 \nabla \times {E} = -\frac{1}{c} \frac{\partial {B}} {\partial t}
 \nabla \times {B} = \frac{1}{c} \left( \frac{\partial {E}} {\partial t} + 4\pi {J} \right)
! Common Structure of the Maxwell and GEM Equations Given Planck units

  • \nabla \cdot {E} =  \iota 4\pi\rho
  • \nabla \cdot {B} = 0
  • \nabla \times {E} = -\partial {B}/ \partial t
  • \nabla \times {B} =  \iota 4\pi{J} + \partial {E}/ \partial t
  • \iota  = 1 (Maxwell) or -1 (GEM) \,

Adopting Planck units eliminates G and c from both sets of equations by normalizing these constants to 1. The two sets of equations are now identical but for the minus sign preceding 4π in the GEM equations. These two minus signs stem from an essential difference between gravity and electromagnetism: electrostatic and magnetic forces of the same type repel, while gravity assures that two positive masses attract. Hence the GEM equations are simply Maxwell's equations with mass (or mass density) substituting for charge (or charge density), and -G replacing.

The factor of 4π that recurs in these equations equals, by definition, the mantissa of the permeability of free space μ0. The value of μ0 is 10-7 for SI units, and 1 for Planck and CGS units. The unnormalized (SI units) version of the fourth Maxwell equation is:

 \nabla \times {B} = \mu_0 {J} + \mu_0 \epsilon_0 \frac{\partial {E}} {\partial t} = \frac{1}{c^2} \left( \frac {{J}} {\epsilon_0}  + \frac{\partial {E}} {\partial t} \right)

where ε0 is the permittivity of free space, and μ0ε0 = c-2. Centimetre gram second system of units and Planck units both normalize the Coulomb force constant to 1. Hence such units effectively normalize ε0 to (4π)-1, whence the factor of 4π in the CGS and Planck versions of Maxwell's equations. Normalizing G to (4π)-1 and ε0 to 1, so that G and the Coulomb force constant become identical, eliminates the factor 4π from the table above.

Some of the higher-order gravitomagnetic effects can begin to reproduce effects reminiscent of the interactions of more conventional polarized charges. For instance, if two wheels are spun on a common axis, the mutual gravitational attraction between the two wheels arguably ought to be greater if they spin in opposite directions than in the same direction. This can be expressed as an attractive or repulsive gravitomagnetic component.

Gravitomagnetic arguments also predict that a flexible or fluid toroidal mass undergoing minor axis rotation ("smoke ring" rotation) will tend to pull matter preferentially in through one throat and expel it from the other (a case of rotational frame dragging, acting through the throat). In theory, this configuration might be used for accelerating objects (through the throat) without them feeling conventional g-forces, although whether this is a practical suggestion is not clear.

Consider a toroidal mass with two degrees of rotation (both major axis and minor-axis spin, both turning inside out and revolving). This represents a "special case" in which gravitomagnetic effects generate a chiral corkscrew-like gravitational field around the object. The reaction forces to dragging at the inner and outer equators would normally be expected to be equal and opposite in magnitude and direction in the simpler case involving only minor-axis spin. When both rotations are applied simultaneously, these two sets of reaction forces can be said to occur at different depths in a radial Coriolis field that extends across the rotating torus, making it more difficult to establish that cancellation is complete.

Modelling this complex behaviour as a curved spacetime problem is very difficult. Gravitomagnetic field of Earth is 10-14 rad.s-1 ("Experimental Detection of the Gravitomagnetic London Moment" by Martin Tajmar, Florin Plesescu, Klaus Marhold & Clovis J. de Matos) A paper by S J Clark and R W Tucker, "Gauge symmetry and gravito-electromagnetism". (Class. Quantum Grav. volume 17 pages 4125-4157), claims to have measured a gravitomagnetic field created by an accelerating superconducting disc, giving, for such a small and light object, a very strong field of 10-4g.

Use of the gravitomagnetic analogy for a simplified form of the Einstein field equations is firmly part of General Relativity. It is an approximation to the current standard theory of gravitation, and has testable predictions, which in the final stages of being directly tested by the Gravity Probe B experiment. In the light that the use of magnetism in gravitomagnetism and the similarity of the GEM force laws to the electromagnetic force law, gravitomagnetism should be remembered when encountering unconventional topics such as:

  • The "Electric Universe", which claims to identify gravity as a form of electromagnetism;
  • Anti-gravity device claims; and,
  • Eugene Podkletnov's gravity-shielding devices and gravitational reflection beams.

String theory and gravitons

String theory is a model of fundamental physics which may be able to avoid problems associated with the presence of point-like particles in theories of physics, in particular the problem of defining a sensible quantum theory of gravity. Studies of string theories have revealed that they predict not just strings, but also higher-dimensional objects. Interest in string theory is driven largely by the hope that it will prove to be a consistent theory of quantum gravity or even a theory of everything, as it naturally describes interactions similar to electromagnetism and the other forces of nature. During the mid-1970s it was discovered that the same mathematical formalism can be used to describe a theory of quantum gravity. This led to the development of bosonic string theory, which is still the version first taught to many students. This early string model - the bosonic string, which incorporated only bosons, describe - in low enough energies - a quantum gravity theory, which also includes (if open strings are incorporated as well) gauge fields such as the photon (or, more generally, any Yang-Mills theory). However, this model has problems. Most importantly, the theory has a fundamental instability, believed to result in the decay (at least partially) of space-time itself. Additionally, as the name implies, the spectrum of particles contains only bosons, particles which, like the photon, obey particular rules of behavior. Roughly speaking, bosons are the constituents of radiation, but not of matter, which is made of fermions. Investigating how a string theory may include fermions in its spectrum led to the invention of supersymmetry, a mathematical relation between bosons and fermions. String theories which include fermionic vibrations are now known as superstring theories; several different kinds have been described, but all are now thought to be different limits of one theory (the M-theory). Gravity, within string theory, acts in the hidden dimensions affects other non-gravitational forces such as electromagnetism.

According to string theory, new symmetry principles that constrain the parameters and reduce them to a finite set where all of the excitations of the string essentially manifest themselves as new symmetries. Through the generalization of the quantum field where instead of point particles, string-like objects propagate in a fixed spacetime background. Arrising from string theory origins in the study of quark confinement and not of quantum gravity, the was the discovery that the string spectrum contains the gravitons. Through string theory "condensation" of certain vibration modes of strings, an equivalent modification of the original background can be undertaken. In this sense, string perturbation theory exhibits exactly the features one would expect of a perturbation theory that may exhibit a strong dependence on asymptotics (as seen, for example, in the AdS/CFT correspondence) which is a weak form of background dependence

The graviton is a hypothetical elementary particle that transmits the force of gravity in the framework of quantum field theory. If it exists, the graviton must be massless (because the gravitational force has unlimited range) and must have a spin of 2 (because gravity is a second-rank tensor field). Gravitons are postulated because of the great success of the quantum field theory (in particular, the Standard Model) at modeling the behavior of all other forces of nature with similar particles: electromagnetism with the photon, the strong interaction with the gluons, and the weak interaction with the W and Z bosons. In this framework, the gravitational interaction is mediated by gravitons, instead of being described in terms of curved spacetime like in general relativity. In the classical limit, both approaches give identical results. However, attempts to extend the Standard Model with gravitons run into serious theoretical difficulties at high energies (processes with energies close or above the Planck scale) because of infinities arising due to quantum effects (in technical terms, gravitation is nonrenormalizable.) Some proposed theories of quantum gravity (in particular, string theory) address this issue. In string theory, gravitons (as well as the other particles) are states of strings rather than point particles, and then the infinities do not appear, while the low-energy behavior can still be approximated by a quantum field theory of point particles. In that case, the description in terms of gravitons serves as a low-energy effective theory. Since gravity is very weak, there is little hope of detecting single gravitons experimentally in the foreseeable future. String theory predicts the existence of gravitons and their well-defined interactions which represents one of its most important triumphs. A graviton in perturbative string theory is a closed string in a very particular low-energy vibrational state.

The Spacetime Model

The Spacetime Model is an new theory which explains 53 enigmas of Quantum Mechanics and modern Physics: quarks, antimatter, nature of elementary particles.... It also explains what mass and gravity are. This theory is nothing but an extension of Einstein Spacetime and, contrary to other theories, it requires only four dimensions: x, y, z and t. To get additional informations concerning gravity, please see the dedicated web site www.mass-gravity.com.

Zero-point energy and cosmology

In cosmology, the zero-point energy offers an intriguing possibility for explaining the speculative positive values of the proposed cosmological constant. In brief, if the energy is "really there", then it should exert a gravitational force. In general relativity, mass and energy are equivalent; either produces a gravitational field. One obvious difficulty with this association is that the zero-point energy of the vacuum is absurdly large. Naively, it is infinite, but one must argue that new physics takes over at the Planck scale, and so its growth is cut off at that point. Even so, what remains is so large that it would visibly bend space, and thus, there seems to be a contradiction. There is no easy way out, and reconciling the seemingly huge zero-point energy of space with the observed zero or small cosmological constant has become one of the important problems in theoretical physics, and has become a criterion by which to judge a candidate "Theory of Everything".

The Putative Tie Between Anti-Gravity and Energy

Many researchers believe that the harnessing of certain exotic energy sources such as from the Zero Point or from magnetic forces, will be accompanied by associated and inseparable anti-gravity effects. John Searl is probably the foremost in alleging such a connection. Another account tells of a magnet motor, which when engaged lifted off the bench and would have gone through the roof if a researcher had not quickly grabbed the shut-off lever. (Ref: witness Welton Meyers at told to Sterling Allan.) Another account tells of a Truck that was being run on a Joe Cell lifting off the ground a couple of inches. (Ref.) These effects have not been scientifically reproduced and documented but are anecdotal.

Patents

"Antigravity"
Electrohydrodynamics

Historically numerous patents have been granted for various applications of the effect, from electrostatic dust precipitation, to air ionizers, and also for flight. A particularly notable patent — U.S. Patent 3,120,363 (G.patent; PDF) — was granted to G.E. Hagen in 1964, for apparatus more or less identical to the later so called "lifter" (ionic propulsion device) devices. Other ionic US patents of interest: 2022465, 2182751, 2282401, 2295152, 2460175, 2636664, 2765975, 3071705, 3177654, 3223038, 3120363, 3130945. An analysis of this cumulative research can be found in Article:Development_of_Ionic_Electrical_Thrust_Technology.

Non-American patents
  • GB300311A method of and an apparatus or machine for producing force or motion — T. T. Brown
US Patent applications
  • Hippensteel, Joseph B., Patent Application 20040192522, "Antigravity full range of motion four limb dry swim exercise machine". September 30, 2004.
  • Ochi-Okorie, Chidiebere E., United States Patent Application 20040251995, "Automotive ball system". December 16, 2004.

External articles, readings, and references

Journals, books, and papers
  • Oleg D. Jefimenko, "Causality, Electromagnetic Induction, and Gravitation: A Different Approach to the Theory of Electromagnetic and Gravitational Fields". Electret Scientific, 2nd ed., Star City, 2000.
  • Heaviside, Oliver, "A gravitational and electromagnetic analogy". The Electrician, 1893.
  • Thomas Valone "Progress in Electrogravitics and Electrokinetics Aviation and Space Travel".
  • "Anti-Gravity and the Unified Field", Edited by David Hatcher Childress, (1990) Adventures Unlimited Press, Stelle, Illinois ISBN 0-932813-10-0. (A collection of pseudoscientific essays, including The Vortex Arena by John Walker, How I Control Gravity by T. Townsend Brown and Anti-mass generators in UFO Propulsion by Kenneth W. Behrendt)
  • "Toward Flight without Stress or Strain ... or Weight," Interavia, Vol. XI, No 5, 1956, pp. 373-374.
  • "Electro-gravitic propulsion," Interavia, Vol. XI, No. 12, 1956, p. 992.
  • Cook, Nick, The Hunt for Zero Point, New York: Broadway Books, 2001.
  • Clark, S J, R W Tucker (2000). "Gauge symmetry and gravito-electromagnetism". Class. Quantum Grav. 17: 4125-4157. DOI:10.1088/0264-9381/17/19/311.
  • Forward, Robert (1963) "Guidelines to antigravity," American Journal of Physics 31: 166-70 (Members only access).
  • Jantzen, Robert T.; Carini, Paolo; and Bini, Donato (1992). "The Many Faces of Gravitoelectromagnetism". Ann. Physics 215: 1-50. eprint version
  • Mashhoon, Bahram (2000). "Gravitoelectromagnetism." Nov 3, 2000.
  • Mashhoon, Bahram (2003). "Gravitoelectromagnetism: a Brief Review". November 8, 2003. A recent introduction to GEM by a leading expert.
  • Tajmar, M.; and de Matos, C. J. (2001). "Gravitomagnetic Barnett Effect". Indian J.Phys. B 75: 459-461.
  • John Archibald Wheeler (1990) A journey into gravity and spacetime. See pp.232-233 ("Gravity's next prize: Gravitomagnetism").
  • Talley, R .L., "Twenty First Century Propulsion Concept". PLTR-91-3009, Final Report for the period Feb 89 to July 90, on Contract FO4611-89-C-0023, Phillips Laboratory, Air Force Systems Command, Edwards AFB, CA 93523-5000, 1991.
  • Tajmar, M., "Experimental Investigation of 5-D Divergent Currents as a Gravity-Electromagnetism Coupling Concept". Proceedings of the Space Technology and Applications International Forum (STAIF-2000), El-Genk editor, AIP Conference Proceedings 504, American Institute of Physics, New York, pp. 998-1003, 2000.
  • Tajmar, M., "The Biefeld-Brown Effect: Misinterpretation of Corona Wind Phenomena". AIAA Journal, Vol 42, pp 315-318 2004.
  • Buehler D.R. Exploratory Research on the Phenomenon of the Movement of High Voltage Capacitors, Journal of Space Mixing, April 2004, vol. 2, pp. 1-22.
  • Jerome J. The mass and gravity enigmas, Edited by AC42 ISBN 97829531234-0-1.
Electrokinetics and electrogravitic
Anomalous effects
General websites

See also

ANTI-GRAVITY FOOTER

ANTI-GRAVITY TECHNOLOGIES

ANTI-GRAVITY RELATED

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