The Milky Way's Dark Halo is Flattened and Twisted ⚡ экспресс
Scientists reconstructed the shape of the Milky Way's dark matter halo by tracking the motions of giant stars, using a new dynamical model. The halo turned out to be triaxial, with its long and middle axes lying in a plane perpendicular to the galactic disk—like a donut standing on edge. Probably, the Milky Way's disk used to be oriented the same way, but then it flipped due to minor mergers with dwarf galaxies. This explains both the observed plane of satellites and links the disk's evolution with the shape of the dark halo.
The Milky Way's stellar disk is like a glowing pinwheel, and тёмное вещество is an invisible cloud around it. For the first time, its shape has been precisely measured. Astronomers tracked the motions of millions of stars and built a 3D map of the тёмное гало out to 160,000 light-years. Back in the day, Фриц Цвикки and Вера Рубин proved the existence of hidden mass, but its distribution remained a mystery.
The picture was stunning. The гало is not spherical, but elongated and flattened, like a deflated rugby ball. And its long axis sticks out almost perpendicular to the stellar disk — as if an invisible frame had been tilted by 90 degrees. This orientation matches the plane in which the dwarf satellite galaxies orbit.
Such a tilt is simply explained: billions of years ago, the Milky Way's disk flipped under the gravitational pressure of small galaxies. Computer simulations confirm this. The discovery ties the стандартная космологическая модель to the actual behavior of galaxies and finally explains the enigmatic plane of satellites.
🎯 There is five times more dark matter than ordinary matter. Without its invisible gravity, galaxies would fly apart from centrifugal force.