No. 67: Jan-Feb 1990
Hyperion is a 150-kilometer-diameter satellite of Saturn. Hyperion's irregular shape and the gravitational pull of Titan, a larger satellite of Saturn, make it a prime candidate for chaotic motion. After accumulating 53 Hyperion-days of observation, J. Klavetter has confirmed this theoretical suspicion. Hyperion's brightness varies wildly from day to day, as it spins unpredictably. The laws of motion and the largest computers are helpless here; although computer simulation can identify situations where chaos might develop.
More alarmingly, some "subtle" chaos also appears in computer simulations of Pluto's motion and "perhaps other planets."
(Kerr, Richard A.; "First Direct View of Solar System Chaos," Science, 246: 998, 1989.)
Comment. Contemplate what might happen -- or might have happened already -- if any of the other planets moved chaotically.