Question

Spiral arms result from density waves in a disk galaxy. Star formation occurs in these arms. As the material in a galaxy interacts with a spiral density wave, clouds compress and dust lanes form. Then, the dense gas clouds ignite with star formation. What is the evidence in this image that supports the claim that the stars are moving faster than the density waves?

A. Bright stars can be found on the leading edges of the arms.

B. Bright stars are only found on the trailing edges of the arms.

C. Dust clouds form on the leading edges of the arms.

D. Ionization nebulae form on the trailing edges of the arms.

Answer 1

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