Antigravity refers to a hypothetical force or effect that repels matter rather than attracting it, essentially working in the opposite direction of the gravity we experience every day. It has never been reliably demonstrated in a laboratory, but the concept sits at the intersection of several real areas of physics, from dark energy pushing galaxies apart to theoretical predictions about how antimatter might behave. Understanding what antigravity actually means requires separating the physics from the science fiction.
Gravity in Reverse
Normal gravity is purely attractive. Every object with mass pulls on every other object with mass. Antigravity, in its simplest definition, would be a gravitational interaction that pushes instead of pulls. This isn’t the same as counteracting gravity with another force (like a magnet holding a paperclip against a refrigerator). True antigravity would mean gravity itself changes direction.
The distinction matters. Technologies like magnetic levitation use electromagnetic forces to oppose gravity, but gravity is still pulling downward the entire time. The object floats because a stronger force is pushing it up, not because gravity has been turned off or reversed. An antigravity device, if one could exist, would modify or cancel the gravitational pull itself.
What Negative Mass Would Do
The most direct route to antigravity in theory involves negative mass, a concept that sounds absurd but isn’t technically forbidden by Einstein’s general relativity. Hermann Bondi pointed out in 1957 that negative mass doesn’t actually contradict the equations of general relativity, even though Einstein himself added conditions to avoid such solutions.
Negative mass would behave in deeply counterintuitive ways. Push it and it accelerates toward you. Pull it and it moves away. When placed near ordinary positive mass, something strange happens: the negative mass gravitationally repels the positive mass, while the positive mass gravitationally attracts the negative mass. The result is that the two chase each other in a straight line forever, with neither gaining nor losing energy. A mix of negative and positive mass could theoretically have near-zero inertia, meaning it could accelerate to enormous speeds with almost no energy input.
Negative mass also shows up as a theoretical requirement for exotic structures like wormholes. The geometry of a wormhole forces parallel paths to diverge, which mathematically requires the presence of negative mass. The same applies to any hypothetical faster-than-light travel. These remain purely theoretical, and no one has ever observed negative mass in nature.
Dark Energy as Cosmic Antigravity
The closest thing to antigravity that scientists have actually observed is dark energy, the mysterious phenomenon driving the universe to expand faster over time. About five billion years ago, the repulsive effect of dark energy overwhelmed the attractive gravity of all the matter in the universe, and cosmic expansion shifted from slowing down to speeding up. Galaxies are now being pushed apart at an accelerating rate.
No one knows exactly what dark energy is. The leading explanation is the cosmological constant, where empty space itself contains energy that generates this repulsive push. An alternative idea, called quintessence, proposes that a previously unknown field pervades the universe and produces the opposite effect of normal matter and energy. Either way, dark energy accounts for roughly 68% of the total energy content of the universe, making it the dominant force shaping cosmic structure on the largest scales.
Dark energy doesn’t behave like the antigravity of science fiction, though. It operates only at vast cosmic distances and has no detectable effect on anything smaller than galaxy clusters. You can’t harness it to float a car or launch a spaceship.
Does Antimatter Fall Up?
One long-standing question in physics was whether antimatter might experience gravity in reverse, falling upward instead of downward. Some theoretical work applying a principle called CPT symmetry to general relativity predicted that matter and antimatter should gravitationally repel each other.
In 2023, a team at CERN put this to the test. Using the ALPHA-g apparatus, researchers released antihydrogen atoms from magnetic confinement and watched how they moved. The result, published in Nature, was clear: antihydrogen fell downward, consistent with normal gravitational attraction to Earth. Repulsive antigravity between antimatter and Earth was ruled out. The experiment opens the door to more precise measurements of exactly how strongly antimatter responds to gravity, but the basic direction is settled.
Failed Experiments and False Starts
The most famous claim of laboratory antigravity came from Eugene Podkletnov, a Russian physicist who reported in 1992 that a spinning superconducting disk could reduce the weight of objects placed above it by about 0.05%. A later version of the experiment allegedly achieved 1 to 2% weight loss. The claims generated significant media attention and prompted several independent teams to attempt replication.
None succeeded. A detailed replication effort using sintered ceramic superconductor disks matching Podkletnov’s published descriptions, supplemented by personal communications with Podkletnov himself, found no evidence of any gravity-like force. The experiment was run three times at full scale. No weight modification was detected down to a sensitivity of 0.001%, which is fifty times more precise than Podkletnov’s original claim. The scientific consensus is that the effect was not real.
Why Building an Antigravity Device Is So Hard
Even if the physics allowed for gravitational manipulation, the energy requirements would be staggering. One theoretical approach involves creating a plasma of electrons moving at a significant fraction of the speed of light, which would effectively double their mass through relativistic effects. Reaching this state would require heating a gas to roughly 5 billion Kelvin, a temperature comparable to the interior of a collapsing star. For context, the core of our sun is about 15 million Kelvin.
Gravity is by far the weakest of the four fundamental forces. The electromagnetic force between two protons is about 10^36 times stronger than the gravitational force between them. This weakness makes gravity extraordinarily difficult to manipulate at human scales. Every approach that has been seriously modeled requires energy densities far beyond anything current or near-future technology can produce.
Quantum Gravity and Gravitational Repulsion
One recent line of theoretical work suggests that gravitational repulsion might emerge from quantum mechanics under very specific conditions. When a source mass is placed in a quantum superposition (existing in two locations simultaneously) and then measured in a particular way, a nearby probe mass can appear to move away from it rather than toward it. This isn’t antigravity in the traditional sense. It’s a consequence of the quantum superposition of gravitational fields and a measurement technique called postselection, where you filter results based on a specific outcome.
What makes this interesting is not the prospect of a hovering car, but what it reveals about gravity at the quantum level. If spacetime itself can exist in quantum superpositions, the implications for unifying gravity with quantum mechanics are significant. The repulsive effect is real within the framework of the calculation, but it applies to individual quantum measurements, not to macroscopic objects you could stand on.
Antigravity in Practical Terms
For now, antigravity remains a concept with no working technology behind it. The closest real phenomenon, dark energy, operates on scales too large to be useful. Antimatter falls the same direction as regular matter. Every laboratory claim of gravity modification has failed independent replication. And the energy scales needed to even begin manipulating gravity are billions of times beyond current capabilities.
That said, antigravity is not purely fantasy. It appears in legitimate solutions to Einstein’s field equations, in the observed acceleration of the universe, and in quantum gravity calculations. The gap between these theoretical footholds and anything resembling a practical device is enormous, but it is a gap in engineering and energy, not necessarily in the laws of physics themselves.