celestial mechanics
branch of astronomy
Position of the Sun
Apparent location of the Sun in the sky
orbital mechanics
field of classical mechanics concerned with the motion of spacecraft
N-body problem
problem of predicting the individual motions of a group of celestial objects interacting with each other gravitationally
lunar theory
theoretical description of motion of Earth's moon
Perihelion Precession of Mercury
Natural phenomenon, where the position of Mercury's perihelion moves relative to the Sun.