- By Prateek Levi
- Sat, 07 Feb 2026 10:37 PM (IST)
- Source:JND
A recent scientific study implies that dark matter, which was hypothesised to have a much larger presence than normal matter, meaning it's speculated to be more abundant, might actually be nothing at all. Our current cosmological models factor in the presence of dark matter in them, and removing it would mean that gravity behaves differently on larger scales, according to Naman Kumar, a scientist from the Indian Institute of Technology (IIT).
For scientists, dark matter has been central to the puzzle of modern cosmology, because despite the fact that it is thought to be more abundant than normal matter, it is invisible to us. That happens because, unlike normal matter, it does not interact with light, or precisely electromagnetic radiation. Scientists have been trying to find the clues of particles that could form dark matter. Now the search for these particles might be unnecessary if what Naman Kumar says is true about gravity behaving differently on very large scales.
"The mystery of dark matter—unseen, pervasive, and essential in standard cosmology—has loomed over physics for decades," Kumar wrote for Phys.org, as quoted by Space. "In new research, I explore a different possibility: rather than postulating new particles, I propose that perhaps gravity itself behaves differently on the largest scales."
Till now the reason why scientists have believed that there is a presence of dark matter is because this matter does interact with gravity. The first clues to which were discovered when galaxies spinning at fast speeds were observed, and if gravity were the only thing holding them together, then they would have flown apart long ago. Gravitational lensing also gives us some evidence. It is basically when the usually straight path of light gets curved due to the presence of objects with very high mass, like galaxies themselves, a phenomenon that was also photographed by the James Webb Space Telescope (JWST). The observed deflection exceeds what visible matter can explain, and this led to a theory that galaxies are surrounded by extensive amounts of dark matter.
Now, since most evidence of dark matter depends on gravity and its effects on space and ordinary (baryonic) matter, a modified theory of gravity, as Naman Kumar proposes, could potentially eliminate the need to search for dark matter.
How Was It Investigated?
To investigate, Kumar examined gravity using quantum field theory at very small scales, comparable to infrared light wavelengths, in a so-called "infrared running scheme". This approach does not assume that Newton’s gravitational constant (“Big G”) is fixed across all distances. Kumar wrote that this creates “a compelling theoretical case” in which gravity’s effective strength subtly shifts over galactic scales. Normally, gravity follows an inverse-square law (1/r²), meaning its strength decreases with the square of distance. In Kumar’s model, the gravitational potential deviates from this law, producing a long-range 1/r force that can account for galaxy rotation curves without invoking dark matter halos.
"These results suggest that the infrared running scenario could account for galaxy rotation without invoking a dominant cold dark matter component," Kumar explained.
Looking Ahead
Kumar’s findings, published in Physics Letters B in 2025, come with an important caveat: if gravity does vary, those changes have to be extremely small to stay in line with what we see in the early universe. His proposed framework reflects that balance. It allows gravity to evolve gradually, staying compatible with cosmic background observations at early times, before beginning to differ at much later stages of the universe’s development.
Looking ahead, Kumar plans to test the strength of the model by matching its predictions against real-world observations, including gravitational lensing effects and data from galaxy clusters. While he is clear that this approach does not yet offer a complete alternative to dark matter, he argues that it opens up an intriguing possibility — that gravity itself may be more complex than current theories assume.