Rivers were used to turn watermills and the Romans even used geothermal water for heating. Until the middle of the 18th century renewable sources of energy were the only forms of energy available, but then, with the advent of the Industrial Revolution, fossil fuels began to be exploited.
The Sidereal Zodiac is the position of the sun referenced against the star background, as a measure of the flow of time. The framework for the star background is the constellations the sun passes in front of. This is the one astronomers use.
Aries the animal. Aries is the astrological Zodiac sign that represents the constellation Aries. In the tropical zodiac, Aries is from March 21 to April 21 beginning at the vernal equinox. Under the sidereal zodiac, it is now from April 15 to May 15. The opposite sign to Aries is Libra.