H.G. Wells dreamt up an innovation that allowed anything placed above it to be freed from gravitational constraints and rise or hover indefinitely. This works as science fiction, but in science fact, such a perpetual motion machine would seemingly violate the law of energy conservation.
Further, gravity cannot be blocked as if it were light or sound, said a highly-reliable source, Albert Einstein. For the General Theory of Relativity holds that gravity is a result of the way mass distorts space-time.
Those holding the opposing view embrace a highly hypothetical notion called electrogravitics. This faux field is populated primarily by enthusiasts of UFOs, free energy, and conspiracy theories. Internet videos purportedly show airborne capacitors working in a vacuum, meaning they would be receiving neither propulsion nor wind. The medium in which these devices are being demonstrated – online videos – allows for no independent testing of the claims.
Some proponents grasp onto the notion of gyroscopes, which produce a force that, when twisted, seems to lift operate independent of gravity. Although this force is known to be illusory, it has still led to numerous claims that anti-gravity devices have been achieved. None of these works have ever been demonstrated to work under controlled conditions.
Still, believers have hyped many inventions that supposedly achieved anti-gravity effects. In 1921, high schooler Thomas Townsend Brown noticed that Coolidge tubes seemed to change mass depending on where they were placed on a scale. Inspired, he refined a series of devices until he had managed to create a type of large capacitor which he asserted demonstrated anti-gravity abilities. Scientists who have studied Brown’s devices have found no such effects and instead attribute the observed force to ionic drift or ion wind.
In 1989, it was reported that a weight decreases along the axis of a right spinning gyroscope, but further testing showed null results. Three years later, Russian researcher Eugene Podkletnov claimed to have discovered that a fast rotating superconductor reduced the gravitational effect. Many studies have attempted to reproduce Podkletnov’s experiment, always to negative results.
Then Ning Li and Douglas Torr wrote in Popular Mechanics that they had built a working prototype of an anti-gravity device, but no further evidence of this prototype has been offered.
Meanwhile, Henry Wallace invented a series of rotating devices that consisted of rapidly spinning brass discs which he said created a gravitomagnetic field. Again, no independent testing or public demonstration of these devices followed.
To a skeptic, these repeated failures are a sign the devices don’t work as advertised. To a conspiracy theorist, it’s a sign our overlords are repressing valuable technology. Depending on how far down the rabbit hole a believer is, this technology is sometimes said to be the result of reverse engineering an alien spacecraft.