The calendar says the sun will rise at six o'clock. But how can that be? After all, the sun does not rise at the same time everywhere. It rises at different times in different places! This is true even for people who live just a few miles apart.
To better understand this, consider "Jack" and "Jill." Jack lives behind Cold Mountain. Jill lives in front of Cold Mountain. Jack and Jill live on opposite sides of Cold Mountain. But they still live just five miles apart. When the sun rises, the front of Cold Mountain is bathed in light. Jill looks out her window and sees the sun. At this same time, however, the back of Cold Mountain remains in shadow. And it is still dark outside Jack's window.