New research led by Durham University astronomers suggests the Milky Way galaxy experienced a dramatic change in orientation, known as a 'disk flip,' where its galactic disk tilted by more than 90 degrees.
According to the researchers, the flip occurred about 10 billion years ago and was caused by a collision with the Gaia Sausage, a dwarf galaxy that struck the Milky Way in a head-on impact.
The findings are based on supercomputer simulations of galactic dynamics, which indicate that galaxies with slowly rotating stellar halos are more likely to undergo such a disk flip.
