What would this be?

[Neil]

Not sure where to post this but seeing as the pic was taken on Marcy posting it here.

What is the dark triangle in the left background? Btw, the pink glow is something called Belt of Venus. Never heard of it til today. I tried to post the image itself but no go so here's a link.

 

[bignslow]

Correct me if I'm wrong, but wouldn't that be the shadow of Marcy being shown on the clouds?

 

[vegematic]

Here's another example and a brief explanation from APOD
If you've ever taken an art class you've likely learned about perspective.
-vegematic

 

[Neil]

As usual, a simple explanation. Thanks!

 

[OnAClearDay]

As usual, a simple explanation. Thanks!

Here's the triangle from Mt Hood, Oregon

 

[Neil]

Here's the triangle from Mt Hood, Oregon
Wow! Awesome shot.