Which description matches an irregular galaxy?

Which description matches an irregular galaxy?

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

Answer: (D)

An irregular galaxy is described by its lack of a regular, symmetric shape. It doesn’t have the flat disk and spiral arms of a spiral galaxy, nor the smooth, rounded glow of an elliptical; instead, it appears chaotic and patchy, with stars, gas, and dust scattered unevenly. This often comes from gravitational interactions or past mergers that disturb the structure. Irregulars are typically rich in gas and show active star formation in bright, clumpy regions, unlike dwarf spheroidals, which are faint and gas-poor with little new star formation. So the description that fits an irregular galaxy highlights its irregular, nonuniform appearance and ongoing star formation.

An irregular galaxy is described by its lack of a regular, symmetric shape. It doesn’t have the flat disk and spiral arms of a spiral galaxy, nor the smooth, rounded glow of an elliptical; instead, it appears chaotic and patchy, with stars, gas, and dust scattered unevenly. This often comes from gravitational interactions or past mergers that disturb the structure. Irregulars are typically rich in gas and show active star formation in bright, clumpy regions, unlike dwarf spheroidals, which are faint and gas-poor with little new star formation. So the description that fits an irregular galaxy highlights its irregular, nonuniform appearance and ongoing star formation.