The Sun is life for all biological life forms. It is a giant helium fusion reactor where hydrogen atoms combine under extreme temperature and pressure to form helium atoms, and emit energy for life on earth in the process. The earth revolves around the sun every three hundred sixty five days six hours and nine minutes. The path the earth takes around the sun is not quite a circle. It is the shape of an ellipse with an electricity of 0.0167.
The eccentricity of the ellipse is a measure of the shape of the ellipse. That is, how circular (basketball shaped) or oval (football shaped). Thus, we see the eccentricity is almost 0.That is, the circular path of the Earth around the sun is nearly a circle , but not quite.
The Earth rotates about its Axis like a spinning basketball on someone's finger. The point the finger connects with the basketball is the axis of rotation. The axis of rotation points to the north star, which currently happens to be Polarus. Polaris is the last star on the handle of the Little Dipper. Remember, the wise men in the bible navigated at night by the North Star, because they lived in the northern hemisphere, but that was over 2000 years ago, and Polarus was not the North Star during the days of Jesus. 5000 years ago (3000 B.C.) the north star was Alpha Draconis ( latin for dragon). However, between 5000 and 2000 years ago during the days of Jesus the rotational axis pointed between Alpha Draconis and Polaris. There was no direct pole star/axis relationship. One had to approximate.





The Axis of rotation of the Earth is not perfectly aligned with the ecliptic or the plan of the path of revolution of the Earth about the Sun. That is, the axis of Earth's rotation is not at a right angle to the path the Earth takes around the sun. If that was the case the sun would always be above the equator and we would have no seasons. The axis of precession is perpendicular to the ecliptic. The earth precesses like a spinning gyroscope about the axis of precession. The axis of rotation is tilted 23.5 degrees from the axis of precession. The precessional axis of the earth takes about 26000 years to complete full revolution. This is very slow when compared to human years. A human would not notice this in their lifetime.



As the earth moves around the sun, the tilt of the axis causes the north hemisphere to be closer to the sun part of the year (summer) and the southern hemisphere to be close to the sun in the other part of the year. For an observer on earth it appears the sun traces a path over the sky rising high overhead in the summer and low overhead in the winter. This Path is also known as the ecliptic, It is the path of the sun as seen from an observer on earth. The sun rises everyday do to the rotation of the Earth about it's axis, but the position on the horizon where it raises changes because of the tilted rotational axis and the Earth's position in its yearly revolution. Thus, marking seasonal changes. So, if an observer stood on the beach looking east over the water, the observer would notice the sun rises at a position ( point on the horizon) toward the north in the summer and at a position toward the south in the winter in the northern hemisphere, and somewhere in between in the spring and autumn. The first day of spring is when the sun is directly over the equator. In present day life that occurs on March 19th, and the length of day is equal to the length of night equinox. From this point forward the suns light will shine longer each day. The Christian holiday of Easter, celebrated to remember that Jesus rose from the grave, hence, the son has risen, is determined to be the first Sunday afer the first full moon past the spring equinoxes. It is a celestial holiday marking the return to life.