1. But is the lack of light based on what one can see (what kids might assume) or the total lack of electromagnetic radiation?
2. Same response as 1.
3. Is space a 3 dimensional volume of 'space' or the space between stuff? Energy as in photons? Are there no gaps between photons? It gets very theoretical here
4. Comes back to the theorectical. We theorize photons as particles, so might there not be space between them and if there is, might the space be 'nothingness' and therefore lack energy? Could space be it's own form of energy? - Hey I don't know anything about this stuff so don't quote me
5. It means we don't know......