Science ❯ Astronomy ❯ Planetary Motion

Orbital Mechanics

Retrograde Motion Elliptical Orbits Ecliptic Path Planetary Speeds Venus Planetary Alignments Mercury's Orbit Ecliptic Plane Saturn's Orbit

Saturn Reaches Opposition Sunday With Rare Titan Shadow Transit Overnight

The ringed planet’s yearly opposition brings peak brightness under a moonless sky for easy backyard viewing.

Six-Planet Parade Continues as Mercury Rises and Moon Approaches