A team of researchers using the Subaru Telescope identified the outermost edge of the Milky Way –the boundary of the stellar system that makes up the galaxy. Its ultimate size is 520,000 light years in radius, 20 times larger than the 26,000 light years between the galactic center and our solar system. The galaxy is so big that it is impossible to identify the halo traces located at the outer boundary using 2.5 to four-meter telescopes.
“Beautiful as it is, our Universe is constantly evolving, often through violent events like the Milky Way’s forthcoming collision with the Large Magellanic Cloud,” said Carlos Frenk, Director of the Institute for Computational Cosmology at the University of Durham. “Barring any disasters, like a major disturbance to the Solar System, our descendants, if any, are in for a treat: a spectacular display of cosmic fireworks as the newly awakened supermassive black hole at the center of our galaxy, Sagittarius A*, reacts by emitting jets of extremely bright energetic radiation.”
An enormous “something” appears to have torn a hole in part of the Milky Way’s halo. The “dark substructure” was found via Gaia spacecraft observations—a mission producing the most detailed 3D map of our galaxy—with Harvard’s Ana Bonaca noticing a perturbation in a tidal stream. Bonaca is a leading authority on how the tidal field of the Milky Way galaxy disrupts globular clusters, and what the resulting debris can tell us about the underlying distribution of dark matter.