EclipsesEclipses

ShadowsShadows• Umbra - the darker part of a shadow

where all the light is blocked

• Penumbra - a partial shadow

• These terms also apply to Solar Eclipses and Lunar Eclipses.

Penumbra

Umbra

Partial Shadow

Full Shadow

Solar Eclipse

Sun

Moon

Earth

• A solar eclipse occurs when the Moon passes in front of the Sun.

Lunar Eclipse

Sun

EarthMoon

• A lunar eclipse occurs when the Moon passes into the Earth's shadow.

Questions

• Which type of eclipse is dangerous to view with the unprotected eye?

• Why are lunar eclipses more commonly seen than solar eclipses?

*

You will observe a total eclipse of the sun when...

(a) you stand in the penumbra of the moon’s shadow

(b) you stand in the umbra of the moon’s shadow

(c) sunlight diffracts around the moon

(d) sunlight reflects from the moon to the earth

(b) you stand in the umbra of the moon’s shadow