Earth's Shadow & Belt of Venus ~ Bradley Allen imaged the scene looking eastwards after sunset in the Cottonwood Lakes region of California's Sierra Nevadas. ©Bradley Allen, shown with permission.

For the Northern Hemisphere, now and onwards through winter is a good time to see the Earth's shadow shortly before dawn in the west and after sunset in the east.

After sunset look eastwards to see a purple-gray band rising from the horizon. This is the shadow of the solid earth cast through the still sunlit higher atmosphere. As the shadow rises it gets less and less distinct until finally it merges with the twilit sky. The dark shadow is topped by a rosy pink glow - the 'anti-twilight arch sometimes called the 'Belt of Venus'. The glow is highly reddened sun rays backscattered by the atmosphere.

Look westwards before dawn to see the reverse sequence. As the sky lightens the Earth's shadow becomes more and more dark and distinct as it sinks towards the horizon.

How did the Belt of Venus get its name? More about that in a later OPOD.


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