Research conducted by a team from the University of Geneva indicates that dark matter behaves under gravity laws similar to ordinary matter. Published in Nature Communications, the study provides insights into this elusive and invisible component of the universe, which is believed to constitute approximately five times the amount of ordinary matter.
The investigation aimed to determine whether dark matter interacts with gravity in the same way as visible matter. While ordinary matter obeys four well-defined forces—gravity, electromagnetism, and the strong and weak nuclear forces—dark matter’s behavior has remained largely a mystery. The research team sought to establish if dark matter falls into gravitational wells created by massive celestial bodies, akin to how ordinary matter, such as planets and stars, operates.
Understanding Dark Matter’s Behavior
To explore the dynamics of dark matter, the researchers compared the velocities of galaxies across the universe with the depths of gravitational wells. Camil Bonvin, an associate professor at the University of Geneva’s Faculty of Science and co-author of the study, explained, “If dark matter is not subject to a fifth force, then galaxies—which are mostly made of dark matter—will fall into these wells like ordinary matter, governed solely by gravity.”
The research findings suggest that dark matter behaves similarly to ordinary matter, adhering to Euler’s equations of motion. This conclusion indicates that dark matter does indeed fall into gravitational wells as ordinary matter does. However, the study does not dismiss the possibility of an undiscovered force affecting dark matter’s behavior. As Nastassia Grimm, the first author and former postdoctoral researcher at UNIGE, noted, if such a fifth force exists, it must be weaker than 7% of the strength of gravity; otherwise, it would have been detected in their analyses.
Future Research Directions
These findings represent a significant advancement in understanding dark matter. The next step for researchers will be to investigate whether a fifth force governs dark matter. Isaac Tutusaus, a co-author of the study and a researcher at ICE-CSIC and IEEC, highlighted that upcoming projects like LSST (Large Synoptic Survey Telescope) and DESI (Dark Energy Spectroscopic Instrument) are expected to offer further insights. “These experiments will be sensitive to forces as weak as 2% of gravity, allowing us to learn even more about the behavior of dark matter,” he stated.
As scientists continue to unravel the complexities of dark matter, the implications of these findings could reshape our understanding of the universe. The research underscores the importance of ongoing collaboration and exploration in the field of cosmology, aiming to bridge the gaps in our knowledge about this mysterious substance.
For more detailed information, the study can be accessed in Nature Communications under the title “Comparing the motion of dark matter and standard model particles on cosmological scales.”
