Researchers from the Center for Applied Space Technology and Microgravity at the University of Bremen and the University of Transylvania in Brașov have unveiled a groundbreaking theoretical framework that challenges our understanding of the universe’s accelerating expansion, potentially rendering dark energy obsolete. They suggest that this acceleration may be an intrinsic characteristic of space-time geometry, rather than a result of unknown cosmic forces.
This artist’s impression traces the evolution of the universe from the Big Bang, through the formation of the Cosmic Microwave Background, to the emergence of galaxies. Image credit: M. Weiss / Harvard-Smithsonian Center for Astrophysics.
For over 25 years, scientists have been puzzled by the unexpected observation that the expansion of the universe is accelerating, counter to the gravitational pull.
In the 1990s, astronomers identified this acceleration through observations of distant Type Ia supernovae, leading to the prevalent theory of dark energy, an invisible force believed to drive this expansion.
Nevertheless, the actual nature of dark energy remains elusive within the Standard Model of cosmology.
Dr. Christian Pfeiffer and his team propose that we may better understand this cosmic acceleration by re-evaluating the geometric framework used to describe gravity.
Central to modern cosmology is Einstein’s theory of general relativity, which details how matter and energy shape space-time.
The universe’s evolution is modeled using the Friedman equation, which originates from Einstein’s principles.
The researchers introduce an innovative solution based on Finsler gravity, an extension of Einstein’s theory.
This approach enhances our understanding of spacetime geometry and allows for a more nuanced exploration of how matter, especially gases, interacts with gravity.
Unlike general relativity, which depends on rigid geometric forms, Finsler gravity presents a more versatile space-time geometry.
With this methodology, the authors recalibrated the equations governing cosmic expansion.
Informed by the Finsler framework, the modified Friedman equation predicts the universe’s acceleration phenomena without necessitating the introduction of dark energy.
In essence, the accelerating expansion emerges directly from the geometry of space-time itself.
“This is a promising hint that we may explain the universe’s accelerating expansion partly without dark energy, drawing from generalized space-time geometry,” Pfeiffer remarked.
This concept does not entirely dismiss dark energy or invalidate the Standard Model.
Instead, it implies that some effects attributed to dark energy might have their roots in a deeper understanding of gravity.
“This fresh geometric outlook on the dark energy dilemma provides avenues for a richer comprehension of the universe’s foundational laws,” stated Dr. Pfeiffer.
The research team’s paper is published in the Journal of Cosmology and Astroparticle Physics.
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Christian Pfeiffer et al. 2025. From a moving gas to an exponentially expanding universe, the Finsler-Friedman equation. JCAP 10:050; DOI: 10.1088/1475-7516/2025/10/050
Source: www.sci.news
