A strange flickering light

The Valkyrior are warlike virgins, mounted upon horses and armed with helmets and spears. [...] When they ride forth on their errand, their armour sheds a strange flickering light, which flashes up over the northern skies, making what men call the "aurora borealis", or "Northern Lights".

("Bulfinch's Mythology", by Thomas Bulfinch, 1855)

Polar Auroras, also known as northern and southern (polar) lights, are natural light displays in the sky, particularly in the polar regions, and usually observed at night.
Typically the aurora appears either as a diffuse glow or as "curtains" that approximately extend in the east-west direction. At some times, they form "quiet arcs"; at others ("active aurora"), they evolve and change constantly.

In the beginning it was dark and cold

Whirlpool Galaxy and its companion NGC 5195

The history of light coincides with the beginning of life, since without light, there would be no life.
In cosmogony, the nebular hypothesis is the most widely accepted model explaining the formation and evolution of the Solar System. The nebular hypothesis was first proposed in 1734 by Emanuel Swedenborg an developed in 1755 by the German philosopher Immanuel Kant.
About 4 billion years ago, soon after the Sun was formed, the Earth and other planets were formed from violent explosions and spinoffs from the process that created the Sun. Gradually oceans appeared and sunlight and water gave birth to life (3 Billion BC), eventually, intelligent life (2 Billion BC).

Eclipse

Total eclipse

An eclipse is an astronomical event that occurs when a celestial object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer.
Eclipse is a perfect example of how light and darkness are complementary.