A Dark Matter Sheet Shapes the Motion of the Milky Way

New research suggests the Milky Way and Andromeda lie within a vast, flat sheet of dark matter stretching millions of light-years. Using detailed computer simulations, scientists explain puzzling galaxy motions that once seemed to defy gravity.

This planar structure—bounded by enormous cosmic voids—allows nearby galaxies to follow the universe’s expansion despite strong local gravity, bringing theory and observation into rare alignment in our cosmic neighborhood.

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