The spiral arms are sites of continuous new star formation, accounting for their blue color and pink emission nebulae.

Question

Quizplus · Accepted Answer

Spiral arms are regions of high density in galaxies where gas and dust are more concentrated, leading to the formation of new stars. Young, hot, blue stars dominate these areas, giving the arms their blue color. The presence of pink emission nebulae, which are clouds of ionized hydrogen gas, indicates areas of active star formation, as these nebulae are often found around young, massive stars.

The Spiral Arms Are Sites of Continuous New Star Formation