Astronomers have contemplated for years why the Milky Way, is warped. Data from ESA’s star-mapping satellite Gaia explain the distortion might be attributable to an ongoing collision with another galaxy, which sends ripples through the galactic disc like a rock thrown into the water.
Astronomers have known since the late Fifties that the Milky Way’s disc—where most of its billions of stars live—is not flat; however, somewhat curved upwards on one side and downwards on the other.
For years, they debated what’s inflicting this warp. They proposed various theories along with the influence of the intergalactic magnetic field or the effects of a dark matter halo, a significant amount of unseen matter that’s expected to encircle galaxies.
With its unique survey of over one billion stars in Milky Way, Gaia might keep the key to solving this mystery.
A group of scientists using information from the second Gaia data release has recently approved previous hints that this warp is not static; however, it changes its orientation over time. Astronomers call this phenomenon precession and it could be liked with the wobble of a spinning top as its axis rotates.
Moreover, the speed at which the warp changes is much faster than anticipated—faster than the intergalactic magnetic field or the dark matter halo would permit. That means the warp ought to be formed by something else.