From EarthSky
There are several good times to think about and be aware of Earth’s shadow.
Just like you or me, Earth casts a shadow. Earth’s shadow extends millions of miles into space, in the direction opposite the sun. There are several good times to think about and be aware of Earth’s shadow.
See Earth’s shadow any evening, ascending in the east. You can see Earth’s shadow any clear evening ascending in the eastern sky at the same rate that the sun sets below the western horizon. The shadow is a deep blue-grey, and it’s darker than the blue of the twilight sky. The pink band above the shadow is called the Belt of Venus.
The shadow of the Earth is big. You might have to turn your head to see the whole thing. And the shadow is curved, in just the same way that the whole Earth is curved.
See Earth’s shadow during an eclipse of the moon. Earth’s shadow extends hundreds of thousands of miles into space, so far that it can touch the moon. Whenever that happens, there’s an eclipse of the moon.
When the sun, the Earth and the moon are aligned in space (nearly or perfectly), with the Earth in between the sun and moon, then Earth’s shadow falls on the moon’s face. Then people on Earth see the shadow gradually turn a bright full moon dark in an eclipse of the moon. There are typically two or more lunar eclipses every year. Some are total, some are partial, some are a special kind of eclipse known as…
Read the rest of When can you see Earth’s shadow? with some beautiful pictures and diagrams.
