Having trouble with these:
1. One of the important struggles of pioneeringastronomers was trying to understand how big our galaxy is, andwhere the Sun is located in our galaxy. Explain how RR Lyrae starsand globular clusters were used by Harlow Shapley to answer boththese questions.
2. Radio astronomy has been critical for determining thestructure of our galaxy. Why is it more effective for this purposethan visible light astronomy?
3. Charlie and Monica are arguing about spiral arms.Charlie believes that spirals arms are regions where active starformation takes place, and are like “traffic jams” where the gasand dust is dense. Monica believes that the spiral arms of a galaxyare like a rigid spinning pinwheel, and the gravitationalattraction of the stars to one another keeps them in rigid shape,like sparkles glued to a pinwheel. Whose explanation is moreaccurate, and why?
