Since the discovery of relativity by Einstein, we know that light has some pretty unusual properties, including that the speed of light is the virtual "speed limit" of the universe. When we look to how divinities are described there is invariably a luminous or radiant quality that sustains life
The prolific and erudite Owen Barfield writes:
Here again, in the case of the Light Ether, we get that special emphasis – of the principle within its own principle. Light Ether is the etheric in the etheric. Without going into the question how far it is possible to call any part of light “physical”, I suppose, then, we are not far astray, if we think of this light from the sun that comes flooding in on us through our eyes, when we wake in the morning, as a sort of gateway through which our consciousness can enter into an experience of the etheric world – if we think of light as, shall I say, the etheric par excellence. And that is why I begin by considering our experience of light from this point of view, by considering our experience of the etheric cosmos.
We must, however, distinguish experience of the etheric from ideas we may form about the etheric before we have any experience. These ideas are likely to be – in my case they certainly were – not truly ideas about the etheric at all, but only ideas about the effects of the etheric in the physical." -- Owen Barfield, The Light of the World.
Barfield's description of light as the "etheric in the etheric" might almost be phrased as "the vital within vitality." After all, what is water without the warmth of light? Ice. Even humus is more than half carbohydrates and carbohydrates are formed of water, air, and the energy of light. The value of humus comes from light. As such, it's easy to see why cultures would venerate the Sun. The Sun shines on the righteous and wicked alike, sharing with impartiality to all. If we wish to make plants more receptive to the light streaming in from the cosmos, we must add some carefully decomposed byproducts of light (humus and biodynamic preparations) so the plants "remember" who they are.