Anti-gravity is a theoretical force that would counteract or cancel out gravity, essentially pushing objects apart instead of pulling them together. No device or material has ever been shown to block, shield, or reverse gravity in a laboratory. But the concept shows up in several real areas of physics, from the accelerating expansion of the universe to experiments with antimatter, and it’s worth understanding where the line falls between established science, active research, and science fiction.
How Gravity Works (and What Reversing It Would Mean)
Gravity, as described by Einstein’s general relativity, is the curvature of space and time caused by mass and energy. Every object with mass attracts every other object with mass. True anti-gravity would mean generating a repulsive gravitational effect: not just floating something in the air using magnets or sound waves, but actually making gravity push instead of pull.
General relativity does allow for repulsive gravitational effects under very specific conditions. The math shows that if something called the “strong energy condition” is violated, space itself can expand in an accelerating way, pushing things apart rather than drawing them together. This isn’t just theoretical bookkeeping. It appears to be happening right now on the largest scales of the universe.
Dark Energy: Anti-Gravity on a Cosmic Scale
The closest thing to real anti-gravity that physicists have confirmed is dark energy, the mysterious force driving the universe to expand faster and faster. In the standard model of cosmology, dark energy takes the form of a positive cosmological constant, a term Einstein originally added to his equations. It acts like a repulsive pressure woven into the fabric of space itself.
Current observations show that roughly 71% of the universe’s total energy content is dark energy, with ordinary and dark matter making up the rest. On the scale of galaxies and galaxy clusters, normal gravity dominates. But across billions of light-years, dark energy wins, pushing the universe apart at an accelerating rate. If this expansion continues indefinitely, distant galaxies will eventually recede from us faster than light can travel between them.
This is genuine repulsive gravity in the sense that spacetime itself is doing the pushing. But it operates only on cosmological scales. You can’t bottle it, focus it, or use it to lift a spacecraft off the ground.
Levitation Is Not Anti-Gravity
Videos of objects floating in midair often get labeled “anti-gravity,” but the methods behind them have nothing to do with gravity. Several levitation techniques exist, including magnetic, acoustic, aerodynamic, optical, and electrostatic approaches. Each one works by applying a balancing force through the surrounding medium, counteracting gravity without altering it.
Acoustic levitation, for example, traps small objects at the stable points (nodes) of a standing ultrasonic wave. The sound pressure pushes the object upward with enough force to balance its weight. Diamagnetic levitation uses powerful magnetic fields to repel the weakly magnetic water molecules inside an object, which is how researchers have famously levitated live frogs. These are clever engineering, but gravity is still pulling on the object the entire time. Another force is simply pushing back harder.
The Antimatter Question
One long-standing question was whether antimatter might fall upward in a gravitational field instead of downward. If it did, that would be a form of anti-gravity built into the laws of nature. Most physicists expected antimatter to fall the same way as ordinary matter, but until recently no one had tested it directly.
In 2023, the ALPHA experiment at CERN settled this by observing the motion of antihydrogen atoms in Earth’s gravity. The team tracked whether anti-atoms escaped their magnetic trap upward or downward. The result confirmed the theoretical consensus: antimatter falls down, just like regular matter. There is no built-in gravitational repulsion between matter and antimatter.
Superconductor Claims and Failed Replications
In 1992, a researcher named Eugene Podkletnov published a paper claiming that a spinning superconducting disk could partially shield objects from gravity. A small test mass suspended above the disk supposedly lost about 0.05% of its weight. A later version of the experiment claimed weight losses of 1 to 2%.
Multiple independent teams attempted to reproduce these results. One detailed replication effort, conducted by Hathaway Consulting Services, built a full-scale version of the apparatus and ran the experiment three times, including a control run with a non-superconducting dummy disk to rule out air currents and stray electromagnetic fields. The result: no weight modification or gravity-like force was detected, down to a sensitivity of 0.001%. The team also noted that they could not achieve the exact disk levitation conditions Podkletnov described, which limits how definitive the null result is. But no independent lab has ever confirmed the original claim.
NASA’s Official Look at Anti-Gravity Propulsion
From 1996 to 2002, NASA ran the Breakthrough Propulsion Physics Project, a small research program that investigated whether any known or speculative physics could lead to propulsion systems that didn’t require conventional fuel. Of the 14 research tasks the program included, six reached null conclusions (meaning the idea didn’t work), four remained unresolved, and four showed enough promise to warrant follow-up research. The follow-up opportunities centered on the properties of space itself, inertial frames, and the quantum vacuum, not on any demonstrated anti-gravity effect.
The program was eventually defunded. No anti-gravity propulsion mechanism came out of it.
Quantum Forces That Push Instead of Pull
At the nanoscale, quantum mechanics produces forces between objects that are purely a consequence of energy fluctuations in empty space. The most famous of these is the Casimir effect, where two closely spaced surfaces are pushed together by the difference in quantum fluctuations between them and around them. Normally this force is attractive.
However, researchers have demonstrated that by carefully choosing the right combination of materials and immersing them in a fluid, the Casimir force can be flipped from attractive to repulsive. In one experiment, replacing a gold plate with a silica plate caused a cantilever to bend away from the surface instead of toward it, confirming a repulsive interaction. The measured repulsive force was weaker than the attractive version, and force magnitudes below 10 piconewtons (trillionths of a newton) couldn’t be reliably measured. This could eventually enable “quantum levitation” of nanoscale objects in a fluid and ultra-low-friction devices, but it operates over distances measured in nanometers and has no connection to gravitational forces.
Warp Drives and Exotic Matter
The concept that comes closest to anti-gravity in theoretical physics is the Alcubierre warp drive, proposed in 1994. The idea is to compress space in front of a spacecraft and expand it behind, effectively moving the bubble of space the ship sits in faster than light. The ship itself wouldn’t accelerate at all; space would do the moving.
The catch is enormous. Making this work requires negative energy, a substance with properties opposite to all known matter. On scales larger than subatomic particles, negative energy or negative mass has never been observed. The faster you want the warp bubble to go, the more negative energy you need. Later refinements to the original model reduced the energy requirements somewhat, but they still call for negative energy in quantities that may not exist in nature. The warp drive remains a mathematically valid solution to Einstein’s equations with no known way to actually build one.
Why True Anti-Gravity Remains Elusive
The core problem is that gravity, unlike electromagnetism, has only one “charge.” Electric charges come in positive and negative, which is why you can shield against electric fields or create repulsion. Mass, as far as every experiment has shown, only comes in one sign. Everything with energy gravitationally attracts everything else with energy. Dark energy produces a repulsive effect, but it’s a property of space itself rather than a material you can manufacture or manipulate.
Until someone discovers negative mass, finds a way to locally violate the energy conditions of general relativity, or uncovers entirely new physics, anti-gravity in the popular sense (a device that cancels gravity) remains firmly in the realm of speculation. The universe does push itself apart on the grandest scales, and quantum forces can push nanoscale objects apart under the right conditions. But neither of these translates into the anti-gravity of science fiction.