Ecliptica

The ecliptic is the apparent path of the Sun's motion across the sky as seen from Earth. This apparent motion is caused by the Earth's revolution around the Sun. The ecliptic is not a physical object, but a conceptual circle on the celestial sphere. It represents the plane of Earth's orbit around the Sun.

The ecliptic is a great circle on the celestial sphere and is inclined to the celestial equator by approximately 23.4 degrees, a value known as the obliquity of the ecliptic. This tilt is the reason for Earth's seasons.

The ecliptic serves as the fundamental plane of the ecliptic coordinate system, which is used in astronomy to define the positions of celestial objects. The ecliptic also intersects with the celestial equator at two points called the equinoxes: the vernal equinox (around March 20th) and the autumnal equinox (around September 22nd). At these points, the Sun appears to cross the celestial equator.

The term "ecliptic" originates from the ancient Greek word ekleipsis, meaning "eclipse," as eclipses of the Sun and Moon can only occur when the Moon is near the ecliptic plane. Solar eclipses occur when the Moon passes between the Sun and Earth, while lunar eclipses occur when the Earth passes between the Sun and Moon. Because these celestial bodies must be closely aligned with the ecliptic, eclipses are relatively rare events.