Our Milky Way Galaxy Once Underwent a Dramatic Disc-Flip

Posted by Guy Pirro | 07/25/2026 10:09PM | Comments

The Milky Way may have undergone a dramatic change in orientation during its history according to new research that helps explain a long-standing mystery about our galaxy. Using supercomputer simulations of galaxies like the Milky Way, a team of astronomers from Durham University in the UK found that galaxies with slowly rotating stellar haloes are more likely to have experienced a major 'disc-flip', where the galaxy's disc changed its orientation by more than 90 degrees. This disc-flip is believed to have occurred when the Milky Way Galaxy had a massive head-on collision with a galaxy known as Gaia-Sausage-Enceladus (often simply called “the Gaia Sausage”). Gaia-Sausage-Enceladus was a massive dwarf galaxy that collided with and was absorbed by the early Milky Way about 10 to 11 billion years ago.