Anti-Crepuscular Rays

[BillyGoat]

I hadn't ever witnessed this before. While driving back through Yellowstone, we noticed the sky opposite the sun looked unusual. I thought it was some kind of alien activity but turned out to be anti-crepuscular rays -- crepuscular rays from the sun that appear to reconverge at the anti-solar point.

 

[Oak]

Are you sure it wasn't aliens?

 

[BillyGoat]

Well we weren't all that far from Devil's Tower. Isn't that where the Close Encounters mothership landed?

 

[DRAFTSTUD]

Isn't that where Obama was standing? John

 

[smalls]

I had a tummy ache this morning, then I took some anti-crepusculars and felt much better.

 

[noharleyyet]

...it's not an oozing sore?

Crepuscular and anti-crepuscular rays

Crepuscular rays are areas of brightly-lit air that appear to radiate outwards from the sun when it is setting or rising. They are caused by clouds or mountains near the horizon casting shadows across the sky. Under good conditions the rays can be seen crossing the sky all the way to the point directly opposite the sun, the anti-solar point, where they appear to converge. In fact both the apparent divergence and the apparent convergence are illusions caused by perspective. The sun's rays are parallel but we perceive them as converging in the same way as we perceive a railway track as converging in the distance.