  The famous three-body problem is investigated by means of a numerical
approach with negligible numerical noises in a long enough time interval,
namely the Clean Numerical Simulation (CNS). From physical viewpoints, position
of any bodies contains inherent micro-level uncertainty. The evaluations of
such kind of inherent micro-level uncertainty are accurately simulated by means
of the CNS. Our reliable, very accurate CNS results indicate that the inherent
micro-level uncertainty of position of a star/planet might transfer into
macroscopic randomness. Thus, the inherent micro-level uncertainty of a body
might be an origin of macroscopic randomness of the universe. In addition, from
physical viewpoints, orbits of some three-body systems at large time are
inherently random, and thus it has no physical meanings to talk about the
accurate long-term prediction of the chaotic orbits. Note that such kind of
uncertainty and randomness has nothing to do with the ability of human being.
All of these might enrich our knowledge and deepen our understandings about not
only the three-body problem but also chaos.
