Cosmologists at Durham University suggest the Milky Way may be surrounded by up to 100 more faint satellite galaxies than previously observed, based on high-resolution supercomputer simulations and advanced mathematical modeling.
Presented at the Royal Astronomical Society's National Astronomy Meeting, the research predicts these elusive "orphan" galaxies-nearly invisible due to being stri by Sophie Jenkins
London, UK (SPX) Jul 14, 2025
Cosmologists at Durham University suggest the Milky Way may be surrounded by up to 100 more faint satellite galaxies than previously observed, based on high-resolution supercomputer simulations and advanced mathematical modeling.
Presented at the Royal Astronomical Society's National Astronomy Meeting, the research predicts these elusive "orphan" galaxies-nearly invisible due to being stripped of their dark matter halos-should exist in greater numbers than known. Current data lists 60 confirmed Milky Way satellite galaxies, but new models predict dozens more orbiting closely.
These results bolster the Lambda Cold Dark Matter (LCDM) theory, the prevailing model of the Universe's structure and evolution, which posits that galaxies form within massive halos of dark matter. According to the model, ordinary matter makes up just 5% of the Universe, with 25% being dark matter and the rest dark energy.
Durham's team combined the Aquarius simulation-the most detailed model of a Milky Way-like halo-with the GALFORM galaxy formation code to resolve shortcomings in standard simulations, which typically lose track of faint satellites due to resolution limits.
Dr Isabel Santos-Santos, leading the research, stated: "We know the Milky Way has some 60 confirmed companion satellite galaxies, but we think there should be dozens more of these faint galaxies orbiting around the Milky Way at close distances... One day soon we may be able to see these 'missing' galaxies, which would be hugely exciting and could tell us more about how the Universe came to be as we see it today."
The team also highlighted roughly 30 ultra-faint satellite candidates recently discovered, whose nature remains uncertain. These could belong to the faint galaxy population predicted by the models, offering a potential pathway to confirming the theory observationally.
Professor Carlos Frenk added: "If the population of very faint satellites that we are predicting is discovered with new data, it would be a remarkable success of the LCDM theory of galaxy formation."
Research Report:Milky Way satellite galaxies in LCDM
Related Links
Durham University
Stellar Chemistry, The Universe And All Within It