1. The apparent motion of a planet from east to west as seen from the earth against the background of the stars.
2. The clockwise rotation of a planet, as seen from its north pole. Compare direct motion.
The movement of a body such as a planet from east to west on the celestial sphere; or the movement of a body in its orbit in a clockwise sense as seen from above the Sun’s north pole; or the rotation of a body on its axis in a clockwise sense as seen from above the Sun’s north pole. Motion in the opposite direction is termed direct or prograde motion. Objects with retrograde motion have an orbital or axial inclination greater than 90°. The outer planets appear to move in a retrograde direction temporarily when the Earth catches them up and overtakes them; they are said to describe a retrograde loop.
retrograde motion:
Superior planets appear to move in a retrograde direction as the Earth catches up and then overtakes them.
A planet in direct motion
B stationary point
C planet in middle of retrograde loop
D stationary point
E planet resumes direct motion
- falling stage systems tract
- falling star
- fallopian tube
- fall-out
- fallout
- fall over
- fallowing
- falls
- fall-stripes
- fall time
- false
- false acceptance
- false acceptance rate
- false body
- false cirrus
- false colour
- false consciousness
- False Cross
- false discovery rate
- false drop
- false fruit
- false negative
- false pleasure
- false position
- false position method