Public index · Planetary
Io’s orbit
~42.46 h
Measured
Sidereal orbital period of Io around Jupiter
Io completes one orbit in 1.769 days, about 42.46 hours. Forty-two is the rounding, not the clock. Laplace 4:2:1 with Europa and Ganymede is the physics.
Documentary plate
NASA / JPL / University of Arizona. Galileo SSI, 3 July 1999.
What it supports
A spacecraft-grade orbital period. Laplace resonance with Europa and Ganymede is the physics.
What it does not
Not an integer 42-hour day designed as a sign. Does not glue Io to Adams or to rainbow 42°.
Calculation
1.769137786 d × 24 = 42.459 h
ExactnessApproximate
Form42 as duration
Unithours
Strengthhard