Unraveling the mystery of the Milky Way’s satellite galaxies

Astronomers have solved an outstanding problem that challenged our understanding of how the Universe evolved.


Several satellite galaxies orbiting Milky Way show a bizarre alignment- They appear to be positioned on a big, thin, revolving plane known as the “plane of satellites.” Astronomers had been perplexed by this seeming impossibility for more than 50 years, which caused many to doubt the standard cosmological model.

A new study by an international team of scientists has now found that the plane of satellites in the Milky Way is a cosmological quirk. They used data from the European Space Agency’s GAIA space observatory on a supercomputer to project the orbits of the satellite galaxies into the past and future. They witnessed the formation and dissolution of the plane of galaxies in a few hundred million years or a tiny blink in cosmic time.

The distances of satellites from the Milky Way’s center had not been taken into account in earlier studies based on computer simulations, which caused the virtual satellite systems to appear considerably rounder than the actual ones.

They discovered numerous digital Milky Ways that have a plane of satellite galaxies that is extremely close to the one viewed through telescopes after taking this into account.

Scientists noted“This removes one of the main objections to the standard model of cosmology and means that the concept of cold dark matter remains the cornerstone of our understanding of the Universe.”

Journal Reference:

  1. Sawala, T., Cautun, M., Frenk, C. et al. The Milky Way’s plane of satellites is consistent with ΛCDM. Nat Astron (2022). DOI: 10.1038/s41550-022-01856-z
Latest Updates