A new theory from physicists at the University of Connecticut challenges one of cosmology’s core assumptions: that the universe began with a Big Bang filled with matter. In an August paper, Professor Philip Mannheim and his team present a model where the universe arises purely from geometry, with empty space shaped by curvature and gravitational waves.
Their approach builds on Einstein’s equations, adapting them to a negatively curved universe that evolves without matter, energy, or an explosive start. The idea is that space itself may have enough structure to generate everything we observe.
By applying the field equations to a saddle-shaped geometry, the team shows that expansion can occur naturally, powered only by gravity. In this picture, an empty curved space produces gravitational waves that evolve according to general relativity without particles or dark energy.
The group also revisits the cosmological principle, which assumes the universe looks the same in every direction. Instead of imposing uniformity, the model lets it emerge from geometry. The equations remain self-consistent without assuming isotropy at the outset.
The framework describes a three-dimensional space with negative curvature and a scale factor a(t) that grows linearly with time. This removes any singularity or beginning. The universe extends infinitely into the past, expanding steadily. Adding a cosmological constant yields properties similar to de Sitter space, aligning with observations.
Mathematically, the universe is locally flat in four dimensions but globally shaped by negative curvature. Gravitational waves dominate the dynamics, satisfying the vacuum Einstein equations and propagating without sources. Mannheim’s team derived exact wave solutions, showing how spacetime’s electric and magnetic components can oscillate even without matter.
These waves could leave subtle imprints on the cosmic microwave background through the integrated Sachs–Wolfe effect. For a curvature value of k = -2.3 × 10⁻⁶⁰ cm⁻², the predicted signal declines with angular scale, forming a low-frequency pattern that resembles faint gravitational echoes.
The theory also fits neatly within conformal gravity, which keeps physical laws consistent under local changes in scale. In this framework, effects usually attributed to dark matter, such as galaxy rotation speeds, follow naturally from negative curvature. Conformal models already match supernova data and explain accelerated expansion without extra parameters, and they may help ease the Hubble tension.
Recent results from Planck and the James Webb Space Telescope hint at slight curvature and unexpectedly mature early galaxies, both of which could support this geometry-driven origin.
If correct, the universe may have emerged from quantum fluctuations of the gravitational field alone, long before any inflation-like phase. Future missions such as LiteBIRD could test the idea by searching for the subtle tensor signatures predicted by the model.
Source: Creating a Universe from Nothing as an Alternative to the Cosmological Principle