For decades, astrophysicists have worked under the premise that unseen forces dominate our universe. According to the standard model of cosmology, two mysterious components—Dark Matter and Dark Energy—make up about 95 % of everything in existence. But now, a bold new study from University of Ottawa suggests that we may not need those invisible entities after all.
The research, led by Rajendra Gupta of the Department of Physics, argues that what we interpret as dark matter or dark energy might instead be explained by subtle changes in the strength of nature’s fundamental forces—especially gravity—as the universe ages.
A simple shift in thinking
In the new model, the idea is that the coupling constants of nature—parameters that determine how strong forces like gravity or electromagnetism are—slowly evolve with time and across different regions of space. What this means: as the universe expands and matter spreads out, the average strength of forces might decline.
Here’s how that helps make sense of two major cosmic puzzles:
The accelerating expansion of the universe: In the standard view, dark energy pulls space outward faster and faster. In this new model, the weakening of forces on the largest scales makes it look like there’s an outward push.
The flat rotation curves of galaxies: Stars at the outer edges of galaxies rotate faster than expected if only visible matter is present. This has been attributed to dark matter halos. But the new theory suggests that a varying parameter (denoted α) in the gravity equation changes based on local matter density—acting like extra gravity where matter is sparse, and less so where matter is dense.
The α-factor
A key piece of the model is this parameter α. On very large (cosmological) scales, α behaves approximately as a constant, helping the model reproduce the overall expansion behavior of the universe. On smaller (galactic) scales, where matter is unevenly distributed, α varies depending on how much “normal” matter there is. Lower density → larger effect; higher density → smaller effect. This variation can mimic the sorts of gravitational effects previously chalked up to dark matter.
In short: instead of needing one explanation for dark energy and another for dark matter, this approach uses a single unified equation driven by evolving constants.
Why this matters
If the model holds up under further scrutiny, it could shake the foundations of cosmology. Billions of dollars and decades of experiments have gone into trying to detect dark matter particles and understand dark energy’s nature. If these phenomena are emergent illusions—by‐products of slowly changing physics—then the search for exotic particles might need a fundamental rethink.
Caveats and community response
As with any radical shift in science, this proposal is not yet mainstream. The standard cosmological model—Lambda‑CDM model—has been remarkably successful in explaining a wide range of observations. Critics will ask whether this new model can match all those successes (for example, the cosmic microwave background, large‐scale structure, gravitational lensing) with comparable precision. Indeed, website Astronomy asked: “Are dark matter and dark energy only an illusion?”
The study published by Gupta combines what’s called the “covarying coupling constants (CCC)” idea with a “tired light” concept (light losing energy over long travel distances) to test the model against observational data.
What comes next?
Researchers will likely put the model through rigorous testing:
Can it match detailed galaxy rotation curves across many galaxies?
Does it reproduce gravitational lensing patterns attributed to dark matter?
Can it fit cosmic microwave background data and the growth of structure over time?
Are there predictions that differ clearly from the standard model which can be observationally tested?
If this theory wins support, it may shift the way we look at the universe’s evolution, structure, and ultimate fate.
The University of Ottawa’s new work proposes a bold idea: the curious phenomena of dark matter and dark energy might be illusions. What we’ve been interpreting as invisible mass or mysterious energy could simply arise from the gradual weakening of fundamental forces like gravity, captured by a changing parameter α. While the model is provocative and elegant in its simplicity, it will require extensive testing and comparison with decades of cosmological data to see whether it can replace the prevailing paradigm.
Source: University of Ottawa News — “Dark matter and dark energy may only be a cosmic illusion” (October 1, 2025)