Final answer:
Elliptical galaxies contain older stars and some interstellar matter, with a lack of systematic rotation and new star formation. They range in shape and have complex dark matter estimations due to the orbital directions of stars. Certain active ellipticals show central dust and gas rings with emerging jets.
Step-by-step explanation:
Although elliptical galaxies may not be conspicuously filled with dust clouds, they do contain some interstellar matter. These galaxies range from near-spherical to more flattened ellipsoidal shapes and often consist of older, reddish stars known as population II stars. They lack the prominent spiral arms found in spiral galaxies. Unlike spiral galaxies, stars in an elliptical galaxy orbit its center in various directions, leading to a less systematic rotation pattern that complicates measurements of dark matter content. Additionally, elliptical galaxies are sometimes categorized as 'red and dead' because they typically contain old stars and exhibit little to no new star formation. However, some evidence points to a fascinating aspect of active elliptical galaxies, like the one depicted in Figure 27.13, which shows a ring of dust and gas surrounding a supermassive black hole, and jets that emerge perpendicular to the ring.