What is empty space?
No air pressure. Some loose particles of air, dust, asteroids, radiation, and such
Things move about in empty space just fine scepti. Asteroids, planets, stars, dust, light, individual molecules of air, etc. It's merely an absence of air pressure.
Anyway, I'm still curious regarding your view that light is an end product of sound. If lightning strikes close by, I see and hear it at almost the same time. If it strikes far away, I see it, and have to wait much longer to hear it.
Myself and a few other did an experiment once with a rifle and a target 400 meters away. We positioned ourselves off to the side of the target a bit behind some trees. Someone next to the shooter keyed the mic on a radio as he fired. We heard the gunshot on our radio, followed a second later by the snap (the bullet was traveling faster than sound) and the bullet impacting, followed a another second later by the actual gunshot sound.
Again, how is light the end product of sound when light travels much faster?