1. Eclipses

2. The Sun and Moon occasionally line up so that we have an eclipse. Revolution of the moon causes eclipses. An eclipse is defined as an astronomical event that occurs when one celestial object moves into the shadow of another, partially or fully obscuring it from view. Can only occur when the sun, the moon, and the Earth are lined up perfectly.

3. Two Types of Eclipses: Solar Eclipse Lunar Eclipse

4. Solar Eclipse When the moon travels directly between the Sun and the Earth and casts a shadow on part of Earth (blocks the Sun’s light from the Earth). Only possible at New Moon. Because Earth rotates, it will take only a few minutes to move out of the Moon's shadow.

5. Moon blocks out sun

6. Two Types of Solar Eclipses: Total Solar Eclipse Partial Solar Eclipse

7. Total Solar Eclipse Observers in the “umbra” shadow see a total eclipse where the moon completely blocks the Sun. Umbra – darkest portion of the moon’s shadow.

8. Total Solar Eclipse Total eclipses are rare! Only once every 360 years from one location. The entire Earth does not see a total eclipse. It depends on where the umbra and penumbra fall on the Earth.

9. Partial Solar Eclipse Observers in the “penumbra” shadow see a partial eclipse where the moon blocks part of the Sun. Penumbra – lighter shadow on Earth’s surface.

10. Lunar Eclipse

11. Occurs during a Full Moon when Earth’s shadow falls on the moon. Begins when the moon moves into Earth’s penumbra. As the moon continues to move, it enters Earth’s umbra and you see a curved shadow on the moon’s surface. When the moon moves completely into Earth’s umbra, the moon becomes dark red because light from the sun is refracted by the Earth’s atmosphere onto the moon. About 2-3 per year; last up to 4 hours

13. Why not eclipses every month? The moon’s orbit around the earth is tilted slightly compared to the Earth’s orbit around the Sun. All three objects must be lined up vertically for an eclipse to occur.

14. Earth Moon Plane of earth’s orbit Plane of lunar orbit