Astronomers discover giant cosmic sheet around the Milky Way

For decades, astronomers wondered why most nearby galaxies are speeding away from the Milky Way instead of being pulled in by its gravity. New simulations reveal the answer: our galaxy sits in a gigantic, flat sheet of matter surrounded by huge empty voids. This hidden structure—dominated by dark matter—balances gravitational forces and lets neighboring galaxies drift outward. The discovery finally explains the puzzling motions of galaxies just beyond our Local Group. For about fifty years, scientists have puzzled over another related mystery. Most large galaxies near our own, aside from Andromeda, appear to be moving away from us rather than being pulled inward by gravity. This seems surprising because these gala... [3068 chars]