Scientists Propose Gravity and Spacetime Aren't Fundamental—They Emerge from Deeper Physics

Scientists are rethinking the nature of spacetime and gravity, suggesting they may not be fundamental forces at all. Instead, a team led by physicist Andrea Addazi proposes that both could emerge from deeper, pre-geometric principles. Their work challenges long-held assumptions and offers a fresh path toward unifying quantum mechanics with Einstein's theory of gravity.

The new theory builds on the idea that gravity arises when a larger symmetry breaks down spontaneously. This process, similar to how other forces in physics emerge, would explain why gravity behaves as it does. The Planck mass and the cosmological constant—two key values in physics—are not fixed but instead emerge naturally from the theory's underlying parameters.

Addazi's team reformulated two existing models, the MacDowell-Mansouri and Wilczek frameworks, to show how this breaking of symmetry could work. By using a gauge-theoretic approach, they demonstrated that gravity can be described through SO(3,2) connections, a mathematical structure that ties into loop quantum gravity (LQG). This method produces Ashtekar-Barbero variables, essential in LQG, through a Plebanski-like action. The result is a spacetime broken into tiny, discrete spin networks—matching LQG's quantum description without the problematic singularities found in classical gravity.

The research also introduces a pre-geometric version of the Wheeler-DeWitt equation, a key equation in quantum gravity. This step could help solve the 'problem of time'—a major hurdle in reconciling quantum mechanics with general relativity. Unlike string theory, which requires extra dimensions, this emergent gravity approach stays closer to known physics while potentially explaining the small but puzzling value of the cosmological constant.

By linking pre-geometric models to established quantum gravity theories, the team shows how standard general relativity and its cosmological constant can emerge from symmetry breaking. The work suggests that gravity, rather than being a fundamental force, might be a secondary effect of deeper, unseen processes.

The findings provide a possible route to quantising gravity without relying on string theory. If confirmed, this approach could resolve long-standing issues like the cosmological constant problem and the incompatibility between quantum mechanics and general relativity. The next step will involve testing whether the pre-geometric framework can fully reproduce the predictions of Einstein's theory while addressing quantum effects.