Antigravity: a Down to Earth Appraisal

Kirk Straughen

(Investigator 146, 2012 September)

The concept of antigravity is usually associated with science fiction novels, an early example of which is H.G. Wells' The First Men in the Moon (pub. 1901) where Cavorite, a gravity defying substance, forms the basis of his spacecraft's reactionless drive. However, the most celebrated antigravity device in science fiction is probably James Blish's 'spindizzy,' the gravitron polarity generator mentioned in his Cities in Flight.

Could antigravity be more than just science fiction? Carrying out a Google search on antigravity revealed many sites devoted to the subject from a true believer's perspective. Could it be that all we have to do is reverse the polarity of the gravitational field (or some such thing), and the stars are ours? The purpose of this article is to examine the likelihood of antigravity being possible.

What is Gravity?

I’ll begin this investigation with an outline of what scientific inquiry has revealed concerning the force of gravity, for when we understand the nature of gravitation we will be in a better position to assess the probability of antigravity's existence.

Gravity is one of the fundamental forces of Nature — the force of attraction existing between all material bodies. Isaac Newton's Law of Universal Gravitation was the first successful attempt to scientifically describe gravity and can account for most of the observed planetary motions and tides. Indeed, even in modern cosmology there are many instances where Newtonian calculations are still perfectly adequate.

Although still sufficiently accurate for most applications, Newton's work has been surpassed by the more complete understanding of gravity expressed in Albert Einstein's Theory of General Relativity that describes gravitation as a distortion in the space-time continuum caused by the presence of matter.

A rough analogy of this conception of gravity can be illustrated using a thin sheet of rubber whose two-dimensional surface represents three-dimensional space. When spherical weights of different mass (representing the Sun and planets) are placed upon the sheet they create depressions in its surface — the more massive the sphere, the deeper the depression, with the steepness of the depression's slope corresponding to the strength of the gravitational field.

As can be seen, gravity, unlike electromagnetism, is always attractive because of the way it deforms space. It does not have two possible charges — that of attraction (between unlike charges), and repulsion (between like charges). Consequently, antigravity can't be generated, as there is no polarity to reverse.

Despite these difficulties, a number of claims have been made concerning the detection of anti-gravitational effects, and these shall now be examined.

Experiments in Antigravity

THE PODKLETNOV EFFECT.

An article in New Scientist (September 21, 1996) reported the work of Eugene Podkletnov, a researcher into high temperature superconductivity at the Tampere University of Technology in Finland.

According to the report, Podkletnov found that objects lost up to 2% of their weight when placed above a ring-shaped superconductor spinning at 5000 rpm, and suspended in a magnetic field. Unfortunately, this claim is surrounded by controversy. A paper was to be published in the October issue of the Journal of Physics D Applied Physics, published by the British Institute of Physics, however, according to New Scientist the paper was withdrawn after Tampere University issued a statement denying all knowledge of antigravity research. Indeed, the only organization that seems to have taken these claims seriously is NASA which has spent considerable time and money trying to replicate the results with little success:
"No one took Podkletnov's claim seriously enough to attempt to replicate his work — except NASA. NASA has spent four years and more than \$1 million attempting to repeat it. So far the results have been "inconclusive." In this case, that means researchers measured a weight change of only two parts in a hundred million, which they admit could have just been an artifact of the measurement. Any weight reduction at all would be a revolutionary discovery, but small effects always raise questions about flaws in the experiment." (Robert Park: Voodoo Science, page 137)

GYROSCOPIC ANTIGRAVITY.

Other similar claimants include Hideo Hayasaka and colleagues at the Faculty of Engineering, Tohoku University, Japan who claimed to detect an anti-gravitational effect in spinning gyroscopes.

Their experiment consisted of dropping a gyroscope spinning at 18,000 rpm in an airtight container so that it passed between two laser beams that recorded the time taken to fall the 6 ft separating them. After ten runs the team claimed that the spinning gyroscope took approximately 1/25,000th of a second longer to fall the same distance than when it was stationary.

Unfortunately, this claim did not survive independent scrutiny — the experiment was repeated with greater sensitivity at the Joint Institute for Laboratory Astrophysics in Boulder, Colorado, with negative results.

CAVORITE THOUGHT EXPERIMENT.

Is it possible to invent some kind of material like Wells' fictional cavorite that could shield objects from the force of gravity? It's difficult to see how this could be done using conventional matter because matter itself is responsible for gravity.

An additional argument against a cavorite-like substance is that it would violate the conservation of energy, a fundamental natural law, by enabling us to construct a perpetual motion machine — all that would need to be done is place this miraculous material under one half of a huge wheel.

Because one side of the wheel is always lighter than the other it will be continuously overbalanced, and so be in perpetual motion, thus producing energy out of nothing — a violation of the first law of thermodynamics.

NEGATIVE MATTER THOUGHT EXPERIMENT.

Negative matter is a hypothetical form of matter first proposed by Hermann Bondi in Reviews of Modem Physics (1957). This form of matter is negative in the sense that its mass is opposite in sign to that of normal matter and, strangely enough, the laws of nature do not appear to forbid its existence.

The unusual properties of negative matter, if it exists, could enable us to construct an antigravity engine. In theory this can be done because the gravitational field of a negative matter object would repel all other objects (both negative matter and positive, or ordinary matter), while the gravitational field of a positive matter object would attract all other objects, including those of negative matter.

The reaction between negative and positive matter produces a rather interesting effect — if a sphere of negative matter were placed next to a sphere of positive matter of equal magnitude, then both spheres will move off in the same direction:
"Suppose we have two objects, one made of negative matter and one made of positive matter. The negative-matter object will create a repulsive gravitational field at the position of the positive-matter object. The positive object then responds to that repulsive gravitational field by producing a gravitational force in the direction away from the negative object. The positive mass then accelerates in the same direction as the applied force — away from the negative mass.

In a similar manner, the positive object creates an attractive gravitational field toward the positive mass. The negative object responds to the gravitational field by producing a force in the negative direction — away from the positive object. The force applied to the negative object produces an acceleration. The acceleration, however, is towards the positive object, because the applied force was away from the positive object and the negative mass acts perversely to the applied force. We thus have the expected but paradoxical result that both the positive and negative masses move off in the same direction at a constantly increasing velocity." (Robert Forward: The Power of Negative Matter, Page 37 in New Scientist, 17 March 1990)
At first appearance this strange behaviour appears to violate the conservation of momentum. However, if the masses are equal and of opposite value, the momentum of the system will be zero if they both travel and accelerate together, regardless of speed.

Conclusion

In my opinion an antigravity engine would have to flatten the curvature of space in order to neutralize Earth's gravitational field. However, the reengineering of the space-time continuum is clearly beyond our current technology, and will no doubt remain so for the foreseeable future.

On the other hand, if negative matter is more than a mathematical fiction, and substantial quantities exist in close proximity to Earth, then it may just be possible to construct something like an antigravity engine. However, if it is nothing more than a hypothetical concept (and I think it may be just this) then antigravity, like perpetual motion, will be forever beyond our reach.

Bibliography:

Forward, R. The Power of Negative Matter, New Scientist, 17th March 1990
Nicholls, P. The Science in Science Fiction, Michael Joseph Ltd., London, 1982
Park, R. Voodoo Science, Oxford University Press, New York, 2000
Rothman, M. Pseudoscience on the Internet  www.csicop.org/sb/9612/internet.html
Negative Matter  http://encyclopedia.thefreedictionary.com/Negative%20matter