New study suggests our galaxy could be surrounded by far more satellite galaxies than previously thought
Scientists at Durham University in England have identified signs that up to 100 extremely faint galaxies (too dim to be spotted with current telescopes) may be orbiting the Milky Way.
These elusive objects, referred to as “orphan” galaxies, likely escaped detection because of their very low brightness.
The team reached this conclusion using a cutting-edge approach that merges high-resolution supercomputer simulations with precise mathematical modelling. Their findings were shared at the Royal Astronomical Society’s National Astronomy meeting held in Durham on Friday, ABC News reported.
The simulations suggest the presence of a hidden population of small galaxies clustered around the Milky Way. If future observations confirm this, it could significantly alter our understanding of the galaxy’s surroundings and the formation of cosmic structures!
Isabel Santos-Santos, the lead researcher at Durham University’s Institute for Computational Cosmology, said: “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.”
If telescopes detect these galaxies, it would strongly support the Lambda Cold Dark Matter theory, the leading model of cosmology explaining how galaxies form and the large-scale structure of the Universe, researchers said.
According to the model, galaxies form at the centres of massive clumps of dark matter known as halos. It also proposes that just 5% of the Universe is made up of ordinary matter, 25% is cold dark matter, and 70% is dark energy.
Most galaxies in the Universe are low-mass dwarf galaxies that orbit larger ones like the Milky Way, astronomers said.
These satellite galaxies have long challenged the Lambda Cold Dark Matter (ΛCDM) model, which predicts more companions than previous simulations could explain. However, the new technique enabled researchers to trace the number, spread, and characteristics of these faint “orphan” galaxies more accurately.
The model provides a “clear illustration” of the power of physics and mathematics, said Carlos Frenk, a co-researcher at the Institute for Computational Cosmology.
Current simulations lack the resolution to study faint satellite galaxies and their dark matter halos, leading to gaps in data, researchers said. If the predictions hold true, it would strengthen the Lambda Cold Dark Matter model.
Santos-Santos concludes, “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.”