You look at the galaxy picture and notice big clumps of stars. There isn’t much of a pattern to how the stars are grouped together, they are all just in one big cloud. Do you think this is a young galaxy or an old one?

On the other side of the Hubble Sequence from young spirals are old elliptical galaxies. These galaxies look very different from spiral galaxies. Instead of spiral arms, elliptical galaxies are just big clumps of stars. There is very little gas and dust.

Because there is not much gas and dust, there’s not enough material to make new stars. In general, the stars in elliptical galaxies are old, red stars. These galaxies look the same from all angles, too.

Astronomers used the ages of the red stars in the elliptical galaxies to determine that these galaxies are pretty old. Maybe they were spirals once with gas and dust in spiral arms. But they’ve been around a while, and have probably used up all their gas to make new stars.

Additional images via Wikimedia Commons. Image of NGC 1316 by NASA, ESA, and The Hubble Heritage Team (STScI/AURA).