1. Motions of Earth, Moon and Sun
Intro to Topic 4
Motions of Earth, Moon and Sun

2. DO NOW:
Imagine yourself standing in an open field, as you look up describe the shape of the sky around you.

3. I. Celestial vs. Terrestrial
Celestial Sphere- the things seen in the sky that are outside of Earth’s atmosphere. These include the sun, moon, planets, and stars.
Terrestrial Sphere- used to refer to objects that are a part of Earth, such as rocks, oceans, and clouds.

4. II. Parts of the Celestial Sphere
Horizon- where the land meets the sky (0 degrees)
Zenith- the point directly above your head (90 degrees)

5. III. Movement of Celestial Objects
Every celestial object appears to rise in the east and sets in the west.
Every celestial object moves 15 degrees per hour because the earth rotates 15 degrees per hour.
Celestial objects appear to travel in an arc across the sky
The apparent daily motion of all celestial objects occurs because of the earth’s rotation

6. IV. Star Paths
A. Near the Equator, stars overhead appear to rise in the east and set in the west.
B. Stars over the North Pole move in circles around Polaris.

7. V. Star Trails
The apparent motion of the stars becomes clear when you look at long-exposure photograph of the night sky.
The stars will appear to circle around Polaris at a rate of 15o per hour.

8. What Direction Are the Stars Moving?

9. What are Constellations?
Observed patterns people use to mark the position of stars in the sky
Changes in the night sky can be used to mark the seasons

10. How Can Stars Tell Us The Season?

11. How to Find Polaris
You can use familiar constellations or star patterns to locate other features of the night sky.
The Big Dipper has two bright stars at the end of the bowl called “the pointer stars” because they point to Polaris.
Polaris is the first star in the handle of the little dipper.