Andromeda’s last meal
Astronomers have just discovered what our neighbouring galaxy Andromeda last had for lunch. Andromeda has been snacking on dwarf galaxies for billions of years, and recent observations have now tracked down the stellar leftovers of its previous meals.
“By tracing the faint remains of these smaller galaxies with embedded star clusters, we’ve been able to recreate the way Andromeda drew them in and ultimately enveloped them at different times,” says Dougal Mackey from the Australian National University, who co-led the study.
These traces show that Andromeda was recently feeding from its plane of satellite galaxies (see yellow orbit in the images, right). This surprised astronomers, as these galaxies are at right angles to those it fed on over 10 billion years ago (see pink orbit in the images, right). However, these dwarf galaxies are only an appetiser. The main course is due to arrive in a few billion years, when Andromeda and our own Milky Way collide and devour each other to become one giant galaxy. www.anu.edu.au
Galactic menu: Andromeda shreds incoming galaxies