Every major galaxy is speeding away from the Milky Way, except one — and we finally know why

Illustration of the night sky over a dark, mountainous horizon. The sky shows a large spiral galaxy at an angle on the left and a milky white cloud of stars cross the sky vertically on the right. .

The structure of the local universe is surprisingly flat, according to new research, and this cosmic quirk may save our Milky Way from colliding with countless other massive, nearby galaxies — except one.

For decades, astronomers have made the puzzling observation that our nearest galactic neighbor, Andromeda, is speeding toward a possible collision with our galaxy, while other nearby galaxies are moving away from us. Now, a new study may finally reveal why: A vast, flat sheet of dark matter is drawing those galaxies into deep space.