When a rock the size of mars hit the earth its clear it could alter the axis of rotation. This would explain the 23° 26′ 11.7′ tilt which is why the world has seasons. Other impacts have added more wobbles to the earth’s rotation.
Over the course of 25,772 years the entire zodiac cycles though and starts over in a new cycle. This now known as axial precession.
In ancient times the belief was that the earth was the center of everything. The wandering stars were called planets which moved strangely against the background of fixed stars.
A sundial is imperfect as the precession of the earth’s orbit and the slightly elliptical orbit lead to being as much as a quarter-hour early or late. Tables and graphs of the equation of time that were made centuries ago are now significantly incorrect.
In Egyptian and Roman times the circumpolar stars were used for reference. It was the age of Pisces which was the way the sky was seen at this time. 2,000 years earlier however the age of Virgo was present. 4,000 years earlier was the age of Taurus. The ages change every 2,148 years.
Timocharis (320–260 BC) and Aristillus (~280 BC) concluded that Spica (brightest star in Virgo) had moved 2° relative to the autumnal equinox. He also compared the lengths of the tropical year (the time it takes the Sun to return to an equinox) and the sidereal year (the time it takes the Sun to return to a fixed star), and found a slight discrepancy.
Hipparchus (190-120 BC) concluded that the equinoxes were moving (“precessing”) through the zodiac, and that the rate of precession was not less than 1° in a century, in other words, completing a full cycle in no more than 36,000 years.
When this was observed on early times it was astounding. It was believed only a omnipotent god could move the heavens. This probably lead to the monotheism that is now dominant.
Mithras probably is very old when it was noted that Virgo slayed the bull. The revelation would be so shattering that it was kept secret. In Rome a not very secret faith was based on an astounding fact. The slaying of the bull makes sense when you consider the wobble in the Earth’s rotation. It was so profound to the Romans who were amazed that the fixed stars were not really fixed at all.
Claudius Ptolemy was a Roman astronomer who lived in Alexandria, Egypt, in the 2nd century AD. His attempt to explain the motions of the celestial bodies in context of the sun orbiting the earth became the accepted theory throughout Europe and the Middle East for almost 2000 years.
Mikołaj Kopernik (February 19, 1473 – May 24, 1543) in De Revolutionibus Orbium Coelestium show that what appear to us as motions of the sun arise not from its motion but from the motion of the earth and our sphere, with which we revolve about the sun like any other planet. The earth has, then, more than one motion. The apparent retrograde and direct motion of the planets arises not from their motion but from the earth’s. The motion of the earth alone, therefore, suffices to explain so many apparent inequalities in the heavens. This work ran afoul of religious dogma.
Johannes Kepler (December 27, 1571 – November 15, 1630) was a mathematics teacher at a seminary school in Graz, where he became an associate of Prince Hans Ulrich von Eggenberg. Later he became an assistant to the astronomer Tycho Brahe in Prague, and eventually the imperial mathematician to Emperor Rudolf II and his two successors Matthias and Ferdinand II. He also taught mathematics in Linz, and was an adviser to General Wallenstein. Additionally, he did fundamental work in the field of optics, invented an improved version of the refracting (or Keplerian) telescope, and was mentioned in the telescopic discoveries of his contemporary Galileo Galilei. He was a corresponding member of the Accademia dei Lincei in Rome. Galileo spent the latter years of his life at home after being accused of heresy. Kepler eventually figured out the actual planetary motions after several earlier attempts failed.
Christiaan Huygens (April 14, 1629 – July 8, 1695) invented the pendulum clock in 1656 which was a dramatic improvement over older clocks. He designed a 50-power refracting telescope with which he discovered that the ring of Saturn was “a thin, flat ring, nowhere touching, and inclined to the ecliptic.”
It is only in the last few centuries that modern astronomy has been able to show what has been happening to the Earth etc. It is now known that the Earth revolves around the sun. It is also now know that the earth’s orbit is slightly eccentric (its eccentricity varies) which answers the questions of Timocharis and Aristillus.