Sunday, August 2, 2015

Marvels of Creation - The Sun and the Lunar Cycle

This Persian manuscript made in 1566 is a translation of the famous cosmography Marvels of Creation, originally written in Arabic by the thirteenth-century Persian lawyer, physician, astronomer and geographer Zakariya ibn Muhammad al-Qazwini (1203-1283). The miniatures illustrate the lunar cycle and the path of the Sun’s rays interrupted by the globe of the Earth at the time of a lunar eclipse. Born in the Persian town of Qazwin, Zakariya served as legal expert and judge in several localities in Persia, traveled in Mesopotamia and Syria, and finally entered the circle patronized by the governor of Baghdad. He also wrote a futuristic proto-science fiction tale entitled “Awaj bin Anfaq” about a man who traveled to Earth from a distant planet. 

Credits: Nick Anthony Fiorenza
The Sun spews forth an endless stream of charged particles in all directions. This solar wind blows far out into the solar system and beyond. The Earth's magnetic field shields from direct contact with the solar wind's charged particles. The Earth's magnetic field is rounded towards the Sun, and stretches out in a long tail away from the Sun. The solar wind rushes around and past the Earth and on out into space while the Moon passes through the different sections of the Earths magnetic sphere in its monthly orbit. At New Moon it is always in the upstream portion of the magnetosphere, facing the Sun and downstream in the Earth's tail at Full Moon. At First Quarter, the Moon is to the dusk side of Earth and at Fourth Quarter, the Moon is in the dawn side of the magnetosphere. The 10th and 25th days of the lunar cycle are significant periods because these points are more or less in line with the 45 degrees vector along which solar corpuscular radiation reaches the Earth. At a phase angle of some 315 degrees the Moon effectively blocks and cuts off most of solar radiation during its cycle, while at the opposite point around 135 degrees, the Moon reaches a point of least blockage. When the Moon is less than 3.5 degrees from the plane of the ecliptic, geomagnetic activity reaches a minimum during the Second Quarter and a maximum during Third Quarter.