Log in
Visit Site
Mona Evans
Mona Evans • 29 weeks ago

Lunar eclipse geometry. There are two parts to the Earth's shadow: the penumbra and the umbra. The umbra is darker because Earth blocks the Sun's direct rays, but there is some direct sunlight in the penumbra. You would scarcely notice the subtle darkening of the Moon passing through the penumbra. (Credit: Fred Espenak) Mona Evans, "Lunar Eclipses" www.bellaonline.c...