Stability of the Solar System that keeps the far side of the Moon away from the Earth. Mercury is in a 3:2 spin–orbit resonance. The planets' orbits are chaotic over longer timescales, such that the whole Solar System possesses a Lyapunov time in the range of 2–230 million years. In all cases this means that the position of a planet along its orbit ultimately becomes impossible to predict with any certainty (so, for example, the timing of winter and summer become uncertain), but in some cases the orbits themselves may change dramatically. Such chaos manifests most strongly as changes in eccentricity, with some planets' orbits
One of Our Planets Is Missing depart from this galaxy. "One of Our Planets Is Missing" is regarded by some entertainment critics to be "one of the best [shows] that animated [Trek] spin-off has to offer" and "a highly satisfying episode that nicely encapsulates the "Star Trek" philosophy. The show's "animation competently conveys the size and scope of the marauding cloud" which threatens the Federation world of Mantilles. Spock's "mind-meld with the cloud is both logical and satisfying, and Kirk and Spock's wrestling with the need to protect [all] life-forms is intelligent and provocative." Kirk even discusses the rationalisation for his decision "not to kill today"