The Milky Way is twisted, and astronomers may finally know why. They’re laying the blame on a tilted halo of dark matter that envelopes our galaxy. The common image of our galaxy resembles a flattened disc similar to a vinyl record, but what you might not imagine is the flared skirt at its edge, structured like the outer ring of a frisbee. And when scientists have studied the shape of the Milky Way in great detail, they found the disc of our spiral galaxy to also have a warp, meaning it’s a bit closer to a frisbee that’s been twisted and bent.
These features have remained mysterious for quite a while, but now astronomers from the Center for Astrophysics, Harvard and Smithsonian, have performed calculations that indicate the halo of dark matter enveloping the Milky Way could be ‘off-kilter’, and this could be causing the flared edge and warped shape of our galaxy. Not only might this revelation help us better understand the evolution of the Milky Way, it could also reveal more about the nature of dark matter and how it shapes the overall development of galaxies.
Dark matter is a challenge for scientists to explain because it doesn’t interact with light, making it effectively invisible. The only way scientists have been able to infer the presence of dark matter is via its interactions with gravity and the influence this has on everyday matter and light. Dark matter is the gravitational glue that holds galaxies together. Thus researchers have deduced that most, if not all, galaxies are wrapped in a halo of dark matter. And for the Milky Way that halo of dark matter is thought to extend out past the halo of stars surrounding the galaxy’s main disc and central galactic nucleus.