The Double Sun Rise
RETROGRADE MOTION
PHENOMENON:
The Double Sunrise
In specific regions of Mercury, an observer would see the Sun rise, partially set, and then rise again during a single day.
SUN'S PATH
LOOP-BACK
Apparent retrograde motion.
ORBITAL RATIO
3:2 RESONANCE
Spins 3x for every 2 orbits.
Sources
PERIHELION EFFECT
This happens near perihelion, where Mercury's high orbital velocity briefly outruns its slow rotation.
ORBITAL DYNAMICSVelocity Balance
3:2 RESONANCE
Mercury rotates 3 times for every 2 orbits around the Sun, a unique lock that creates these long solar days.
SPIN-ORBIT MATHResonance Data
RETROGRADE MOTION
The apparent "loop" the Sun makes in the sky is a result of Mercuryβs highly elliptical (oval-shaped) orbit.
MESSENGER DATAApparent Motion
INITIALIZE DOUBLE SUNSET RENDER