How could you determine the circumference of the planet without any further observations? What is the circumference, in miles, of the planet?
1. Suppose Eratosthenes had found that, in Alexandria, at noon on the first day of summer, the line to the Sun makes an angle 30° with the vertical. What, then, would he have found for Earth’s circumference? 2. Suppose you are on a strange planet and observe, at night, that the stars do not rise […]