The Milky Way might have many more neighboring galaxies than we’ve been able to detect so far, according to new research from scientists at Durham University.
Photo Credit: The Aquarius simulation, the Virgo Consortium/Dr Mark Lovell.
The Milky Way might have many more neighboring galaxies than we’ve been able to detect so far, according to new research from scientists at Durham University.
Using powerful computer simulations and advanced mathematical models, researchers now believe there could be 80 to 100 more satellite galaxies quietly orbiting our galaxy—galaxies that current telescopes haven’t yet spotted.
These small, faint galaxies are being called “orphan” galaxies because they’ve been stripped of almost all of their dark matter by the strong gravity of the Milky Way.
Without the dark matter that normally helps hold galaxies together, these orphan galaxies are incredibly hard to see and have likely been missed by both astronomers and computer models—until now.
This new research, which is being presented at the Royal Astronomical Society’s National Astronomy Meeting at Durham University, supports a well-known theory called Lambda Cold Dark Matter (LCDM).
This theory explains how galaxies form and evolve in the universe.
It suggests that most galaxies are born inside large clumps of dark matter called halos. Bigger galaxies like the Milky Way often have many smaller galaxies orbiting around them.
So far, scientists have confirmed about 60 satellite galaxies near the Milky Way, but LCDM predicts many more should exist. That mismatch between theory and what we actually see has been a long-standing puzzle in cosmology.
To solve it, the Durham team used a combination of the highest-resolution simulation of a Milky Way-like dark matter halo, called the Aquarius simulation, and a detailed galaxy formation model called GALFORM.
These tools helped them study how faint satellite galaxies evolve over billions of years—even when their dark matter halos are stripped away by the Milky Way’s gravity.
