Can the Milky Way Cast a Shadow?

Stories of the Milky Way casting a shadow are common but details are elusive. Whenever someone wants to brag about the great dark skies they experienced they often trot out the “it was so dark you could see your shadow by the light of the Milky Way” line. Asking follow-up questions results in repetition and hand-waving.
But could it be true? Is it possible? After all, the Milky Way is large, diffuse, low contrast, and faint. The sun and moon cast shadows. Bright point sources cast shadows. It’s even said that Venus or Jupiter can cast shadows. Can the huge Milky Way, spread across 90 degrees of sky (or more), cast a shadow? In this talk, we move beyond hearsay, legend, and myth and attempt to nail down some facts and experimental results...
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