Ecliptic

Definition

The ecliptic is the apparent path that the Sun traces out in the sky over the course of a year as observed from Earth. It also represents the plane of Earth's orbit around the Sun.

5 Must Know Facts For Your Next Test

1. The ecliptic is inclined at an angle of about 23.5 degrees to the celestial equator due to Earth's axial tilt.
2. The points where the ecliptic intersects the celestial equator are called the equinoxes.
3. The zodiac constellations lie along the ecliptic path.
4. Solar and lunar eclipses occur when the Moon crosses near or on the ecliptic plane during a full or new moon.
5. The ecliptic plane is used as a reference for defining the positions of objects in our solar system.

Review Questions

• What angle does the ecliptic make with respect to the celestial equator?
• Why are solar and lunar eclipses associated with the ecliptic?
• Which constellations are found along the ecliptic path?

Related terms

Celestial Equator:

The imaginary extension of Earth's equator onto the celestial sphere.

Zodiac:

A band of twelve constellations through which the Sun, Moon, and planets move along their paths in the sky.

Equinox:

The two points where the ecliptic intersects with the celestial equator, leading to nearly equal day and night lengths worldwide.