What was light?
It was electromagnetic radiation visible to human eyes. In fact, every intelligent being had a different definition for light since their visual organs have subtle differences, but light is ultimately a high frequency electromagnetic radiation as well as a fundamental atomic flow formed from photons, an existence embodying the wave-particle duality of quantum mechanics.
Those were the text noted in the fifth paragraph on page thirty-five of the Earth Federation's textbooks. Joshua could not be more aware of it and yet he did not answer the old pontiff's question, for this was not Earth but the Extraordinary world named Mycroft, a miracle land of magic, aura, and magic.
Ultimately, none knew what 'light' was.