Originally posted by Mr. X:

It seems like your Skybox-Files are corrupt. The box is the sun.
You have to verify integrity of gamefiles to get the sun-texture.

The sun does not emit lightning.
It seems your Norse lore is lacking.
This would be Thor riding his chariot through the stormclouds.
You have to do some reading and maybe you'll verify the names of the two goats that pull his chariot ;p