A new theory of gravity could explain cosmic acceleration without dark energy

Science News from research organizations A new theory of gravity could explain cosmic acceleration without dark energy Date: January 11, 2026 Source: Universität Bremen Summary: The accelerating expansion of the universe is usually explained by an invisible force known as dark energy. But a new study suggests this mysterious ingredient may not be necessary after all. Using an extended version of Einstein’s gravity, researchers found that cosmic acceleration can arise naturally from a more general geometry of spacetime. The result hints at a radical new way to understand why the universe keeps speeding up. Share: Facebook Twitter Pinterest LinkedIN Email FULL STORY Physicists may have found a way to explain the universe’s accelerating expansion without invoking dark energy. A new approach to gravity suggests spacetime itself could be driving the cosmic speed-up. Credit: AI/ScienceDaily.com Why the universe is expanding faster and faster remains one of the biggest open questions in physics. Current theories cannot fully explain this accelerating growth. Today's standard picture of the universe is built on Einstein's general theory of relativity and the standard model of particle physics. Within this framework, scientists usually assume the presence of a mysterious force known as "dark energy" to account for the speeding expansion of space. Despite its widespread use in cosmology, the true nature and origin of dark energy are still unknown. Now, researchers from the Center of Applied Space Technology and Microgravity (ZARM) at the University of Bremen, working with colleagues at the Transylvanian University of Brașov in Romania, suggest a different way of looking at the problem. Their work indicates that the universe's expansion might be explained -- at least partially -- without invoking dark energy at all.

Why Dark Energy Was Added in the First Place Cosmologists use Einstein's general theory of relativity along with the Friedmann equations to describe how the universe changes over time. However, when these equations are applied to real astronomical observations, they fall short. To match what telescopes see, scientists must manually add an extra "dark energy term" to the equations. This addition is not derived naturally from the theory itself, which has long made it an unsatisfying solution. A New Approach Using Extended Gravity Because of this limitation, the team at ZARM and their Romanian collaborators explored an alternative idea. Their results, published in the Journal of Cosmology and Astroparticle Physics, rely on an extension of general relativity (GR) known as Finsler gravity. This approach has been developeded over recent years and uses a broader description of spacetime geometry. Unlike the standard formulation of GRT, Finsler gravity can describe the gravitational behavior of gases more precisely. This difference turns out to be crucial when modeling the large-scale behavior of the universe.

Accelerated Expansion Without Dark Energy When the researchers applied Finsler gravity to the Friedmann equations, they uncovered a striking result. The modified equations, known as the Finsler-Friedmann equations, naturally predict an accelerating universe even in empty space. No extra assumptions are required, and no additional "dark energy" term needs to be added by hand. "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," says Christian Pfeifer, ZARM physicist and member of the research team. "This new geometric point of view on the dark energy problem opens up new possibilities for better understanding the laws of nature in the cosmos." RELATED TOPICS Space & Time Cosmology Space Telescopes Space Exploration Cosmic Rays Matter & Energy Physics Albert Einstein Quantum Physics Materials Science RELATED TERMS Dark energy Big Bang Dark matter Potential energy General relativity Shape of the Universe Acceleration Ultimate fate of the universe Story Source: Materials provided by Universität Bremen. Note: Content may be edited for style and length. Journal Reference: Christian Pfeifer, Nicoleta Voicu, Annamária Friedl-Szász, Elena Popovici-Popescu. From kinetic gases to an exponentially expanding universe — the Finsler-Friedmann equation. Journal of Cosmology and Astroparticle Physics, 2025; 2025 (10): 050 DOI: 10.1088/1475-7516/2025/10/050 Cite This Page: MLA APA Chicago Universität Bremen. "A new theory of gravity could explain cosmic acceleration without dark energy." ScienceDaily. ScienceDaily, 11 January 2026. . Universität Bremen. (2026, January 11). A new theory of gravity could explain cosmic acceleration without dark energy. ScienceDaily. Retrieved January 11, 2026 from www.sciencedaily.com/releases/2026/01/260110211221.htm Universität Bremen. "A new theory of gravity could explain cosmic acceleration without dark energy." ScienceDaily. www.sciencedaily.com/releases/2026/01/260110211221.htm (accessed January 11, 2026). Explore More from ScienceDaily RELATED STORIES Hidden Dimensions Could Explain Where Mass Comes from Dec. 15, 2025 — A new theory proposes that the universe’s fundamental forces and particle properties may arise from the geometry of hidden extra dimensions. These dimensions could twist and evolve over time, ...

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