Astronomers may have spotted the ghost galaxy that hit the Milky Way long ago
Discovered in Gaia data, Antlia 2 could be the star system scientists have been looking for
The Milky Way survived a galactic hit and run millions of years ago — and astronomers may have finally found the culprit.
Ten years ago, astrophysicists Sukanya Chakrabarti and Leo Blitz of the University of California, Berkeley, suggested that ripples in the outer gas disk of the Milky Way were caused by a collision with a dwarf galaxy that shook the Milky Way’s gas like a pebble dropped in a pond. The pair made predictions for how massive and distant the galaxy had to be, as well as roughly where it should be found. But none of the known dwarf galaxies that orbit the Milky Way fit the bill (SN: 4/4/15, p. 6).