Milky Way sits in flattened matter sheet explaining nearby galaxy movement
Updated
Updated · Sky at Night Magazine · May 9
Milky Way sits in flattened matter sheet explaining nearby galaxy movement
10 articles · Updated · Sky at Night Magazine · May 9
University of Groningen scientists used simulations and data from more than 30 nearby galaxies to show the structure extends tens of millions of light-years and is dominated by dark matter.
They found only a flattened mass distribution matched observed galaxy positions and velocities, with matter in the plane offsetting the Milky Way's gravity so nearby galaxies can keep drifting outward.
The sheet is bordered by large voids above and below it, and future observations may test whether similar structures are common and shape galaxy formation elsewhere.
If an invisible dark matter wall dictates our galaxy's path, what other cosmic structures remain unseen?
Is our galaxy's neighborhood a cosmic anomaly, or are galaxies everywhere trapped inside these dark matter sheets?
Does this newfound 'cosmic sheet' confirm our model of the universe, or hint that it's fundamentally wrong?
The Milky Way’s Local Group Floats in a Vast Dark Matter Sheet: Solving the Mystery of Nearby Galaxy Motions
Overview
For nearly a century, astronomers have puzzled over why most galaxies move away from the Milky Way, while Andromeda heads toward us. This mystery, first noted after Edwin Hubble’s discovery of the universe’s expansion, has now been explained by a breakthrough in March 2026. New research led by Ewoud Wempe and Amina Helmi revealed that the Milky Way and Andromeda are embedded in a vast, flattened sheet of dark matter. This unique arrangement, rather than the total amount of unseen matter, shapes the motions of nearby galaxies and solves a long-standing cosmic puzzle.