The universe might not actually be speeding up—gravity might just be messing with our perspective and making it look that way.
March 13, 2026
Original Paper
Highly homogeneous and isotropic universes: quasi-dust models and the apparent dark-energy evolution arising from the local gravitational potential
arXiv · 2603.11377
The Takeaway
While astronomers usually explain the universe's rapid expansion using a mysterious 'dark energy,' this paper suggests that dark energy might not exist at all. Instead, it argues that local gravitational potentials create a backreaction effect that makes the universe appear to accelerate from our perspective, even if it is actually slowing down.
From the abstract
In this manuscript, we develop a class of inhomogeneous relativistic cosmological models with the following properties: (i) They contain cosmological observers to whom the spatial geometry and the expansion are homogeneous and isotropic; (ii) Matter behaves closely to dust, as it is formed by an ensemble of massive particles whose number density $4$-vector is conserved and reacts viscously to the local tidal forces; (iii) They generalize the dust FLRW model; (iv) They give rise to effective mode