Q Choose one of the following topics to discuss. Your post should be at least 200 words (if you post later in the week, check which topic your classmate(s) have chosen and pick a different topic to discuss): 1. Explain how binary star systems are used to find the mass of stars. 2. Discuss how astronomers determined distances to objects within our solar system. 3. Explain the methods used by astronomers to determine the distances to the nearest stars. 4. Explain how variable stars are used to find cosmic distances. To receive full credit for the post, make sure you respond to at least two of your classmates (one classmate if the total number of students is four or less).