Which description best fits an elliptical galaxy?

Which description best fits an elliptical galaxy?

• A. Spiral galaxy
• B. Elliptical galaxy
• C. Irregular galaxy
• D. Dwarf galaxy

Answer: (B)

Galaxies are classified by their shape and what they contain. An elliptical galaxy is defined by a smooth, ellipsoidal glow without the flat disk or spiral arms seen in other types. Its stars move in many random directions rather than circling in a rotating disk, and there’s very little gas or dust available for new star formation. Because of that, the stellar population is old and the galaxy often looks reddish and featureless. This description fits an elliptical galaxy best because it contrasts with spirals, which have a bright disk with arms and ample gas for ongoing star formation; irregulars, which lack a defined shape; and dwarfs, which are simply smaller and can have varied appearances. The key idea is: smooth ellipsoidal shape, little to no star formation, and little interstellar material.

Galaxies are classified by their shape and what they contain. An elliptical galaxy is defined by a smooth, ellipsoidal glow without the flat disk or spiral arms seen in other types. Its stars move in many random directions rather than circling in a rotating disk, and there’s very little gas or dust available for new star formation. Because of that, the stellar population is old and the galaxy often looks reddish and featureless.

This description fits an elliptical galaxy best because it contrasts with spirals, which have a bright disk with arms and ample gas for ongoing star formation; irregulars, which lack a defined shape; and dwarfs, which are simply smaller and can have varied appearances. The key idea is: smooth ellipsoidal shape, little to no star formation, and little interstellar material.