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Unformatted text preview: Clicker Question #6: (Prather et al. #8c on page 132.) D. 60 million years ago. Clicker Question #7: (Related to Prather et al. #9 on page 132). A. X is older. Why: Suppose they both appear to be 5 years old. Say Y is 3 ly away, and X is 5 ly away. How old are X and Y really? All answers to Prather et al. 131-132: #1: Light-year is a unit of distance, the distance light travels in one year. #2: Sydney lives 4.3 ly from the Sun. #3: 11.4 years -- Crystal's picture takes that long. #5: Yes, the farther away the child lives, the older he/she is when you actually receive his/her message. #6: Crystal sent her picture first and Sydney sent her picture last. #7: As it wasy 2.5 million years in the past. Light takes that long to travel the distance between Andromeda Galaxy and here. #8: 10 million years, 40 million years, 60 million years ago. #9: a and e...
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