Scientists at the University of Bremen and Transylvanian University of Brașov propose a revolutionary theory of gravity that could explain the universe’s accelerating expansion, potentially removing the need for dark energy. Published in the Journal of Cosmology and Astroparticle Physics, their work suggests a more general spacetime geometry is the true driver of cosmic acceleration without dark energy, challenging a long-held cosmological puzzle.
For decades, physicists have grappled with the perplexing observation that our universe is expanding at an ever-increasing rate. This cosmic speed-up, detected in the late 1990s, defied predictions from Albert Einstein’s general theory of relativity and known matter. To reconcile theory with observation, the concept of “dark energy” emerged as a placeholder for this mysterious accelerating force.
While dark energy has become a cornerstone of the standard cosmological model, its true nature remains elusive, prompting continuous efforts to find alternative explanations. This new research offers a compelling geometric perspective, suggesting that the expansion might be intrinsically linked to the very fabric of spacetime rather than an unknown energy component.
The enduring puzzle of dark energy
Cosmologists traditionally describe the universe’s evolution using Einstein’s general theory of relativity and the Friedmann equations. However, these equations, when applied to real astronomical observations of an accelerating universe, consistently fell short. To bridge this gap, scientists were compelled to manually insert an additional “dark energy term” into the equations.
This ad-hoc addition, not naturally derived from the underlying theory, has long been a point of contention and an unsatisfying solution for many physicists. The reliance on an unknown entity to explain such a fundamental cosmic phenomenon underscores the persistent need for a more coherent theoretical framework.
Finsler gravity offers a new cosmic perspective
Driven by the limitations of the standard model, researchers from the Center of Applied Space Technology and Microgravity (ZARM) at the University of Bremen, alongside collaborators at the Transylvanian University of Brașov, explored an alternative. Their study, detailed in the Journal of Cosmology and Astroparticle Physics, utilizes an extension of general relativity known as Finsler gravity.
Finsler gravity employs a broader description of spacetime geometry, differentiating it from the standard formulation of general relativity. This approach allows for a more precise description of the gravitational behavior of gases, a crucial distinction when modeling the large-scale dynamics of the universe.
Applying Finsler gravity to the Friedmann equations yielded a remarkable outcome: the modified Finsler-Friedmann equations inherently predict an accelerating universe, even in seemingly empty space. This eliminates the need for any additional assumptions or the manual insertion of a dark energy term.
Christian Pfeifer, a ZARM physicist and member of the research team, noted: “This is an exciting indication that we may be able to explain the accelerated expansion of the universe, at least in parts, without dark energy, on the basis of a generalized spacetime geometry.” He added that this geometric viewpoint opens new possibilities for understanding cosmic laws, as reported by ScienceDaily on January 11, 2026.
This novel application of Finsler gravity presents a significant shift in how we might interpret the universe’s accelerating expansion. By proposing that the very geometry of spacetime is responsible, it offers a compelling alternative to the enigmatic concept of dark energy. While further research and observational verification are essential, this work from Universität Bremen and its partners paves the way for a deeper, more unified understanding of the fundamental forces shaping our cosmos.
