Abstract: The methodologies, developed in the field of System Science, are valuable in the studies of so complex physical
objects for which models based on first principles are not developed yet. The traditional approach, starts from
the first principles and knowledge about simple physical processes, advances to understanding of more complex
processes and at the final stage conjugates them into an ultimate model of the complicated physical object. In some
sense, the system science advances our knowledge in opposite direction. It builds on the knowledge of generic
complex system behaviour. Applying advanced data analysis methods, it investigates the evolution of the overall
system to provide information about the underlying physical processes involved in system dynamics. The Solar
Terrestrial system is one example of a physical systems that still lacks a comprehensive physical model deduced
from the first principles. The difficulties that currently do not allow the development of such a model for the whole 
magnetosphere, and for its regions, such as radiation belts or ring current, are discussed. Using the evolution of radiation
belts and ring current as examples, it is shown how the system approach can advance our physical knowledge and
provide a reliable forecasting tools.