3. Diurnal and Annual Motion.pptx

Physical Science

1. DIURNAL MOTION ANNUAL MOTION PRECESSION OF THE EQUINOXES

2. DIURNAL MOTION apparent daily motion of the heavens from east to west in which celestial objects seem to rise and set, a phenomenon that results from the Earth's rotation from west to east. The axis of this apparent motion coincides with the Earth's axis of rotation.

3. DIURNAL MOTION Each day, the Earth rotates once (west-to-east)on its axis. This causes us to face different directions and see different stars. The stars daily(diurnal)motion reflects the Earth's spin.

4. ANNUAL MOTION Annual motion of the sky — the appearance that objects in the sky moves relative to the background stars as observed at the same time of the day and at the same location on Earth. Over the course of a year, the Sun appears to move a little towards the East each day as seen with respect to the background stars. This daily eastward drift is <1° per day (there are 365 days in a year, but only 360° in a circle). As the Earth orbits the sun, the sun appears to move eastward with respect to the star.

5. ANNUAL MOTION Due to the Earth's revolution Reflection of the Earth's Orbital Motion

6. PRECESSION OF THE EQUINOXES The Earth axis chages direction in a CLOCKWISE direction with a cycle of about 26,000 years Earth axis also precesses (wobble)like a top. The angle between ecliptic and the equator remains at 23. 5 °. but the direction changes. The period of this precession of the equinoxes is about 26, 000 years