Using data from ESA’s Gaia satellite and archival spectroscopic surveys, astronomers have mapped the Milky Way disk substructure at distances over 10,000 parsecs (32,616 light-years). One possibility is that they are the remains of tidal arms from the Milky Way disk which were excited at different times by various satellite galaxies.”The Milky Way is now surrounded by nearly 50 satellite galaxies and has engulfed numerous such galaxies in its past. Another possibility is that not all these structures are actual genuine fossil spiral arms but instead form the crests of large scale vertical distortions in the Milky Way disk. “Typically this region of the Milky Way has remained poorly explored due to the intervening dust which severely obscures most of the Galactic midplane,” Dr. Laporte said. Kinematics beats dust: unveiling nested substructure in the perturbed outer disc of the Milky Way.

Source: Ethiopian News December 15, 2021 19:54 UTC