Which feature distinguishes spiral galaxies from ellipticals and gives their arms a blue appearance?
Answer
The presence of hot, massive, young stars in regions of active star formation
The spiral arms are regions of active, ongoing star formation, appearing bluer due to the presence of hot, massive, young stars.
Related Questions
Based primarily on what characteristic did Edwin Hubble organize galaxies in his sequence?In the Hubble Tuning Fork Diagram visualization, which class of galaxies occupies the handle?What stellar composition generally defines elliptical galaxies?What does the designation $ ext{E}7$ signify for an elliptical galaxy?Which feature distinguishes spiral galaxies from ellipticals and gives their arms a blue appearance?How does the classification of a spiral galaxy progress from $ ext{Sa}$ to $ ext{Sc}$?What is the defining characteristic of a barred spiral galaxy, such as the Milky Way?Where are lenticular galaxies ($ ext{S}0$) positioned on the Tuning Fork Diagram?Why are Irregular galaxies often described as being in a 'temporary resting place'?What is the primary difference between Peculiar galaxies and standard Irregular galaxies?