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.
The “Planet Earth Report” connects you to the day’s news on the science, technology, discoveries, and events changing our planet and the future of the human species.
Since the Gaia Spacecraft’s April 2018 data release, astronomers have unveiled a Milky Way teeming with astounding surprises, including hints of dark-matter clumps that might eventually provide a better grasp of the elusive material’s properties. These early, easy-to-spot findings, reports Adam Mann in Nature, have been “transformational.” Astronomer Vasily Belokurov at the University of Cambridge, UK, said they are merely a glimpse of what is to come: “How we see the Milky Way has clearly changed.”
This past fall, a team of astronomers detected 10 billion solar masses worth of dark matter from an ancient dwarf galaxy, Gaia-Enceladus, swallowed by the Milky Way billions of years ago carried along by the S1 star stream that harbors our Solar System streaming directly towards the Sun.
