Mystrey of Light in The Universe

Mystery of light in the universe leads to many questions and wonderment:

What prompts light to travel?
What propels the light to travel?
Does light loses energy as it travels?
What the energy is converted to?
Is light sliding say to a lower energy?
Is light packets travel in packets?
What is the space between packets?
Is the space between packets has a distribution function?
What determines the direction of light travel?
Does light search of objects in space to travel to?
Does light reflects back into the universe at its boundary?

How far light will travel to outer of universe into total emptiness
will it round round and back to the universe?
are there black envelop enveloping the universe where every thing will be sucked into