Low atomic density, high speed (less atoms to jump through per meter).
In other words, light is not an object, it is an effect of objects.
There is no complete vacuum because there are objects in space occupying that space. The space is still there and doesn’t go away just because objects occupy it. That would be like saying your closet has no space just because it is full. Your closet remains the same volume whether you have stuff in it or not. Its size is no affected by the content, but of the 3 dimensional distance (volume). The volume of your closet is the space of your closet, regardless of how much “stuff” is in that closet.
Light is slowed down by mass, and it travels at full speed in a vacuum.
No it is not. Light is electromagnetic radiation. Radiation is “particles” traveling in space. The sun produces radiation and it travels from the sun to earth. Radiation can travel its best in a vacuum, and is resisted by mass. Lead is massive, that’s why the dentist will have you wear a lead vest when he takes an x-ray to prevent the radiation from getting to your body.
The radiation is resisted by the lead vest. No vest means maximum penetration! No mass in space means maximum radiation travel.
Agreed - although no space - of any dimension - can be truly totally void of all energy.
So you believe that throughout the billions of lightyears that light travels through space - is actually filled with atoms/mass objects? 
Hahaha so what you are trying to say is that there is no vacum, except everywhere where a massive object isn’t?
I never said there was a place in space that was void of “energy.” There is space and there are objects in space. Space is independent of objects. Objects come and go but space is forever.
That’s a weird quote.
That is the definition of a vacuum.
Space is not a vacuum, there is all sorts of energy measured in it. For just one thing. That energy is equivalent to atomic matter, as Eintein and the bomb proved. Therefore it is atomic matter.
If light is electromagnetic radiation, it has to be explained what exactly that is.
What it is is that electromagnetism, which is an interaction between one electron in one atom and another in another, first involves an effect on the incoming electron whereby a spin change can follow which spin change is electricity. That previous step, that “lining up” of electrons, is what light is. Light exists, on the atomic level, only as a function of electrons in different atoms making a connection.
It is an excitation, not a particle, particle in the sense of having mass.
Light has no mass, I feel silly even having to say this out loud.
Mass is energy - EMR - in tight bundles. Light is not in bundles - rather speeding “puffs” of energy - no inertia.
That is correct, a vacuum by definition means that very thing, a space without mass. A vacuum is not a negative space, it is simply empty space. A vacuum at sea level would be 0 psi atmospheric pressure. As it stands now at sea level the atmospheric pressure is 14.7 psi.
So in your car’s intake manifold when the engine is off (at sea level) the pressure in the manifold is 14.7 psi. On a vacuum gauge that is 0 psi because it is measuring the relative pressure to sea level. The lower the pressure the higher the vacuum. When your car is at a high RPM going down hill and your foot off the accelerator pedal the vacuum in the manifold is almost -14.7 PSI, which in relative terms is just above 0 PSI. So the manifold at that point has almost a complete vacuum and there is almost no air in it.
Sorry the spin change is magnetism, electricity is when the electron actually “jumps,” (which could easily simple be ceases to exist in one and appears in the next) to the next atom.
Quantum leap nonsense.
Right, light has no mass, it is simply one atom interacting with the next, energy. The fastest possible atomic interaction.
That’s mass, not matter. Energy is mass times the speed of light squared.
When people say matter, they tend to mean mass. Just as when they say atom, they tend to mean the electron orbited nucleus. I didn’t tell people what to call things.