Q: It is known that amavasya reduces blood flow intensity of animals and humans, or sap flow of plants. It is known that purnima increases these flows. These phenomena affect our mind deeply. We have been taught that by our gurus. But, why is that so?
A: Because amavasya, when Moon is almost between Earth and Sun (so no or just a little part of it is lit, as we see it) means that Moon is contributing it’s gravity influence on objects on Earth to that of Sun. Thus, the gravity we feel is increased. However, during purnima, when Earth is almost between Moon and Sun, the gravity of Moon opposes that of Sun, and thus the overall gravity we feel decreases. Inherently, lowering gravity force increases the ability of living bodies to lift liquids up, and vice-versa.
Q: Yes, but what happens to our minds, what’s the connection?
A: We perceive the gravity of Earth as constant, and all jivas are able to lift liquids up their body somehow, by construction. This ability of moving liquids within a body is a required condition for life. Animals hearts pump the blood up, while plants are constructed to allow liquids to spread up (by means of osmosis and diffusion Jala spreads up by it’s own design).
Anyway, the ability to cope with Earth gravity is not important now, as it is too constant to be even noticed. The gravity of Sun, however, is very frequently changing the direction from which it influences us, and we are used to this by being used to overwhelmingly dominant day-night chandas. The gravity influence of Sun is in resonance with the day and night changes, it is the same direction, and since it so present, so predictable, it defines the very basis of our biology chandas (feeding at daytime, sleeping at night, etc). Also our very discrimination ability is defined the same way – a duality concept (day/night, yes/no, full/empty…). This does not disturb our minds, as it is in harmony with the Sun, the life pace maker.
However, much subtler, and much less frequent in comparison to the day-night speed, and thus much less predictable to our discrimination, is the speed at which Moon and Sun together form amavasya and purnima phases. Although repeating, the pace of these events disturbs our mind, we can never get used to it on a mind level, as we are simply surprised again and again by the peeks of this influence. A surprise means a disruption of a routine, a stress, that is how it affects our mind. Our biology harmonizes with it and utilizes that pace to time some functions, like menstrual cycles. This urge to procreate reminds us of itself and it contributes to disruption of our mind routine.
Q: Wow, do all Jyotish principles have a physical explanation?
A: Yes they do.