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.
A sidereal day is how long it takes the Earth to turn one full (360 degree) revolution and it takes 23 hours and 56 minutes. A solar day is how long from noon to noon and it takes 24 hours But it spins 361 degrees.