•Problem: How do
you find the position of a planet (say Mars) when you know its direction but not its distance.
•
•Standard
surveying solution: Observe it from two different locations and use “triangulation” or parallax.
•
•Special
Problem: The motion of the Earth lets you make observations from two different positions, but Mars
moves too during this
time.
•
•Kepler’s
special insight: Find an artificial way to make Mars “stand still”
•