Ganymede (moon) every orbit of Ganymede, Europa orbits twice and Io orbits four times. Conjunctions (alignment on the same side of Jupiter) between Io and Europa occur when Io is at periapsis and Europa at apoapsis. Conjunctions between Europa and Ganymede occur when Europa is at periapsis. The longitudes of the Io–Europa and Europa–Ganymede conjunctions change with the same rate, making triple conjunctions impossible. Such a complicated resonance is called the Laplace resonance. The current Laplace resonance is unable to pump the orbital eccentricity of Ganymede to a higher value. The value of about 0.0013 is probably a remnant from a previous
Ring Around the Moon (Space: 1999) from the sphere and enveloped the Moon. Tracking sensors reveal the sphere to be stationary but, from their perspective, it is still getting closer to the Moon's surface; John Koenig realises that the Moon has been trapped in an orbit around the sphere. An audio signal is received and a sibilant voice announces that they are prisoners of the planet Triton. The staff reviews the damage caused by the Moon's sudden deceleration. The fact that all but four are non-operational and the main generators show no sign of damage but are only putting out minimum power indicates that the sphere's