Discovered by S. Nicholson
Date of Discovery 1951
Distance from Jupiter 21,200,000 km
Radius 10 km
Mass 4 × 10^19 g
Orbital Eccentricity 0.16870
Orbital Inclination 147°
Orbital Period 631 days retrograde
Rotational Period ???
Density (gm/cm3) ???
Ananke is one of those cool moons that revolves around its planet in the opposite direction most do, counter to the planet's rotation. Also the orbital inclination is highly atypical. Carme, Pasiphae, and Sinope also share similar approximate distance from Jupiter, inclination, and retrograde motion. This could mean they were once part of the same object, pulled apart by Jupiter's gravity.
Sources:
NASA.gov
space.com