Explain How Giant Molecular Clouds Give Rise to Spiral Tracers

Q17: Discuss the evidence that supports the theory

Q18: The Sun orbits the center of the

Q19: In the late 18th century, two astronomers,

Q20: Harlow Shapley used observations of globular clusters

Q21: What parts of the galaxy are considered

Q23: _ variable stars are useful in measuring

Q24: Spiral arms are clearly visible features of

Q25: What property of a Cepheid variable can

Q26: The center of our galaxy contains a

Q27: Why do astronomers conclude that the spiral