Milky Way's potential number of satellite galaxies may exceed earlier estimates
In a groundbreaking development, researchers at Durham University have unveiled new findings suggesting that the Milky Way could have up to 100 more satellite galaxies than previously predicted or observed. The discovery, presented at the National Astronomy Meeting 2025, could significantly reshape our understanding of galaxy formation and the role of dark matter.
The research, which is based on the Lambda-cold dark matter (LCDM) model, combines the highest-resolution supercomputer simulations with novel mathematical modeling to identify these previously elusive galaxies. The new predicted Milky Way "orphan satellite" galaxies, marked with an 'x' symbol in the Aquarius-A-L1 simulation, are extremely faint and small, making them difficult to detect until now.
The existence of these objects has long posed challenges to the LCDM cosmological model, which posits that galaxy formation occurs within large dark matter halos and that most galaxies are low-mass satellites of bigger ones like the Milky Way. The detection of these galaxies would provide strong support for the LCDM theory.
The research predicts that there could be around 80 to 100 additional faint "orphan" satellite galaxies orbiting close to our galaxy, beyond the roughly 60 confirmed so far. The Durham researchers argue that these objects could be a subset of the faint population of satellite galaxies they predict should exist.
The researchers were able to track the abundance, distribution, and properties of these Milky Way orphan galaxies, showing that many more Milky Way satellites should exist and be observable today. If these galaxies are seen by telescopes, it could provide strong support for the LCDM theory.
The National Astronomy Meeting, principally sponsored by the Royal Astronomical Society (RAS) and Durham University, is a platform for astronomers to share their latest research findings. Durham University, a globally outstanding center of teaching and research based in Durham City, UK, is a member of the Russell Group of leading research-intensive UK universities and is consistently ranked as a top five university in national league tables.
The Science and Technology Facilities Council (STFC), the UK's largest public funder of research into astronomy and astrophysics, among other fields, has played a significant role in supporting this research. The RAS, a UK-based organization that encourages and promotes the study of astronomy, solar-system science, geophysics, and related branches of science, has also been instrumental in facilitating this work.
The talk 'The contribution of "orphan" galaxies to the ultrafaint population of MW satellites' will take place at NAM at 10:15 BST on Friday 11 July 2025. This discovery not only expands our knowledge of the Milky Way but also offers insights into the larger cosmos, reinforcing the standard model of cosmology by illustrating how dark matter influences galaxy formation on both small and large scales.
- The recent discovery of potentially 80 to 100 new, faint "orphan" satellite galaxies orbiting the Milky Way, suggested by the research conducted at Durham University, could provide strong support for the Lambda-cold dark matter (LCDM) theory, which is a key component in the standard model of cosmology.
- The findings, based on high-resolution supercomputer simulations and novel mathematical modeling, indicate that these elusive galaxies, previously difficult to detect, could significantly reshape our understanding of environmental-science, space-and-astronomy, and technology related to the Milky Way and galaxy formation, especially concerning the role of dark matter.
