When a planet is clicked, it should be selected. If a planet is already selected, both planets should become selected, and an appropriately colored line should be drawn from one to the other. There should be a JS handler that deals with the planets' interaction until the link is broken.
When a planet is clicked, it should be selected. If a planet is already selected, both planets should become selected, and an appropriately colored line should be drawn from one to the other. There should be a JS handler that deals with the planets' interaction until the link is broken.