'It's not visible in computer simulations': Hubble maps Andromeda's chaotic history, and it's not what scientists expected

The Andromeda Galaxy, captured in this image by NASA's Spitzer Space Telescope, is the closest major galaxy to the Milky Way, but new Hubble data suggest it evolved very differently. (Image credit: NASA/JPL-Caltech) A major new study by the Hubble…