It is easy to take for granted some of the basic observations that we make about the sky. We see the Sun move across the sky from east to west. That is what we see, what we observe, but as you've learned in school, it is really the Earth and not the Sun that is in motion. We can't feel the Earth moving, and there is nothing we can observe that actually tells us we are moving. You'll explore this challenging subject of motion in the sky, thinking about the Sun, the Moon, and the planets. Their individual movements, and the Earth's, create a dizzying dance across the heavens, and their motions may not be what you think.
Added by Upcoming Robot on July 8, 2012