Consider the classical 3-body problem, where bodies are mutually
attracted by Newton graviation. Call motion oscillatory if as time tends
to infinity limsup of maximal distance among the bodies is infinite, while
liminf is finite. In the 50’s Sitnikov presented the first rigorous example
of ocsillatory motions for the so-called restricted 3-body problem. Later
in the 60’s Alexeev extended this example to the full 3-body problem. A
long-standing conjecture of Kolmogorov is that oscillatory motions have
measure zero. We show that for the Sitnikov example and for the so-called
restricted planar circular 3-body problem these motions often form a set
of maximal possible Hausdorff dimension.