Governments and institutes have investigated assertions by various inventors claiming anti-gravitational effects with high-voltage electrodynamic or gyroscopic devices; however, no such effect has been publicly confirmed. Of course anti-gravity appears to be outlawed under general relativity, gravity being recognized as a geometric property of space deformed by local mass-energy. Anti-gravity is apparently not out of the question. However, the elusive fifth force has not yet been found, and anti-gravitational fields remain the provenance of fiction
Impossible objects