How a Galaxy Can Get Booted From Its Home
Cosmic collisions may slingshot tiny galaxies into intergalactic space.
The cosmic world is full of runaways, including billions of planets and stars. Now astronomers can add entire galaxies to the ranks of the homeless.
A team of Russian astronomers has found evidence that compact galaxies can be gravitationally whipped out of their host galaxy cluster. The study appears today in Science.
Extremely compact elliptical galaxies are generally tight, shaped like a ball, and much smaller than most other galaxies that populate the universe, containing at most a few billion stars. Our own run-of-the-mill galaxy, the Milky Way, in contrast, is home to about 100 billion suns.
These compact elliptical galaxies are fairly rare. Until 2013, only 30 or so had been found, and they were all huddling