Inclination

Inclination (i) is the angle at which the object’s orbital plane (yellow) is tilted, relative to Earth’s orbital plane (grey) around the Sun. A value of 0° means that the object's orbit is parallel with Earth’s orbit. A value of 90° means that the object's orbit is tilted at a right angle to Earth’s orbit. If an object has an orbit with inclination greater than 90°, it will be orbiting in a direction opposite to Earth’s orbital direction.

Examples of orbital ellipses with different inclinations.
An image describing the inclination of an orbit. Credit: Modified from image by Lassuncty, Creative Commons 3.0 Unported.

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