Scientists say up to 100 tiny galaxies could be hiding around the Milky Way

If these hidden galaxies are confirmed by future observations, it would provide strong support for the Lambda Cold Dark Matter (LCDM) theory—the leading model explaining how the Universe formed and evolved. This theory says that most galaxies form inside huge clumps of dark matter called halos.

“Observational astronomers are now using our predictions to help guide their searches,” said Dr Isabel Santos-Santos, lead researcher from Durham University’s Institute for Computational Cosmology. “One day soon we might be able to actually see these ‘missing’ galaxies.”

Looking Deeper Into the Universe

The team’s findings were presented at the National Astronomy Meeting 2025, hosted this week at Durham University. They used data from the Aquarius simulation, one of the most detailed models of a galaxy like the Milky Way, along with GALFORM, a powerful tool that models how galaxies form and change over time.

With the upcoming use of new, more sensitive instruments like the Rubin Observatory’s LSST camera, astronomers are hopeful these faint galaxies will finally come into view.

“This would be a huge success for our understanding of the Universe,” said Professor Carlos Frenk, co-author of the study. “It shows how physics, maths, and computing power can work together to uncover the unseen.”

The research was funded by the European Research Council and the UK’s Science and Technology Facilities Council (STFC), with simulations run on Durham’s COSMA supercomputer.