Islamicate astrometeorologists were the first to replace the ancient practice of observing only short-term signs, such as clouds and the flight of birds, to predict weather. They based their action on the hypothesis that weather is caused by the movements of planets and mediated by regional and seasonal climate conditions. Improved calculations of planetary orbits and updated geographical and meteorological information made the new science possible and compelling. The prospect of acquiring reliable weather forecasts, closely linked to predictions of coming trends in human health and agricultural production, made the new meteorology attractive in Christian Europe too. Considerable pride shines through medieval Christian accounts of the weather questions that they could now start to answer. Central among them was one that classical meteorologists had failed to figure out: How can weather vary so much from one year to the next when the seasons are caused by regular, repeating patterns produced by Earth’s spherical shape and its interactions with the Sun?How did it work? Some of the details are lost, but:
Astrometeorologists noted that the angular relationships between planets were important for determining their mutual effects. Planets facing one another across the zodiac were negatively related; an angle of 45° was also problematic and likely to produce an atmospheric disturbance. However, planets at 60° or 120° would interact more positively and produce more moderate weather. When planets were close together, the intensity of their effects would increase depending on the natures and placements of the planets involved.In other words, plain old vector algebra. One phrase caught my eye:
The techniques in al-Kindi’s method required that forecasters confidently judge which factors would have the greatest effects and for how long, and they accepted that experience was crucial in making a successful prediction. Experts put their trusted methods on record for the benefit of others. Especially influential was al-Kindi’s application of the concept known as “opening of the doors.” The treatises do not explain the phrase, but it hints that rain was caused by an almost physical change in the atmosphere, driven by specific combinations of planets and their movements in relation to one another.Opening of the doors. Here's the Ridhwan clock, designed by and for those Islamic forecasters, combining science with religion and entertainment. By some descriptions, the upper dial rotated seasonally to show the current arrangement of constellations. I didn't try to animate that part. Each hour opened a door revealing the number of the hour. The 12 houses behind the doors may have dispensed something to the priests or people. (The balls transferred to the birds were stacked up like a vending machine, so similar devices for the little houses would have been possible.) Happystar appropriately illustrates. HOW did planetary position control our weather? The astrometeorologists were correct given the state of their knowledge:
Astrologers believed that the planets and the fixed stars, including those making up the constellations to which the houses of the zodiac were linked, had special affinities with individual elements and qualities. Those qualities determined the nature of the effects each planet would have on the terrestrial world as it moved through the heavens.Affinities with elements = magnetic field. The planets pull and shape the field of the entire solar system, giving it a different 3D graph of intensities and declinations for each configuration. As the earth passes through this field, the intensities influence the distribution of heat in our core, cause static fields through the dynamo effect, and influence bacteria in the clouds and nematodes in the soil. Not mysterious or metaphysical, unless you're a follower of the modern astrology that attributes all long-term weather to OrangeTrumpQanon Witch Carbon.
The current icon shows Polistra using a Personal Equation Machine.