Dark matter is often described as invisible material that only shows its presence through gravity, but researchers are now testing whether it may also experience a hidden force of its own. According to ScienceDaily, a new study in the Journal of Cosmology and Astroparticle Physics looked at what would happen if dark matter particles pulled on each other with an extra attractive interaction.
The result was not what scientists first expected. While the additional force helps dark matter clump together more efficiently, the study found that it usually does not speed up the buildup of cosmic structure. In most cases, the combined effect actually slows that growth.
The idea has drawn more attention because several precise measurements of the Universe do not line up perfectly with the standard cosmological model. Some observations suggest the Universe’s expansion may have been a bit slower in the past than expected, while studies of the cosmic microwave background have hinted that matter may be more tightly clustered on the largest scales than predicted.
Researcher Zachary Weiner of the Perimeter Institute for Theoretical Physics, the study’s corresponding author, said the work leaves open the possibility that dark matter has interactions hidden from ordinary matter. The team’s calculations showed that the extra force can also make dark matter effectively lose mass over time, weakening its gravitational effect and offsetting the added attraction.
According to the researchers, that same mechanism could affect a range of theories beyond the study’s simplest models, including some ideas tied to DESI observations. They say more precise data from future observatories and cosmic surveys may help narrow down what kinds of hidden dark matter interactions are possible.
