Astronomy
Elliptical Galaxies and the Role of Mergers in Their Evolution
Quick fact
Most elliptical galaxies contain almost no cold gas and dust, which means they have stopped forming new stars. They are often called 'red and dead' galaxies because their remaining stars are old, cool, and reddish.
Why this is interesting
You've seen gorgeous spiral galaxies with swirling arms, but some galaxies look like fuzzy, featureless blobs. What makes these elliptical giants so different? Their secret lies in a violent history of cosmic collisions.