  The large-scale organization of complex networks, both natural and
artificial, has shown the existence of highly heterogeneous patterns of
organization. Such patterns typically involve scale-free degree distributions
and small world, modular architectures. One example is provided by chemical
reaction networks, such as the metabolic pathways. The chemical reactions of
the Earth's atmosphere have also been shown to give rise to a scale-free
network. Here we present novel data analysis on the structure of several
astrophysical networks including the chemistry of the planetary atmospheres and
the interstellar medium. Our work reveals that Earth's atmosphere displays a
hierarchical organization, close to the one observed in cellular webs. Instead,
the other astrophysical reaction networks reveal a much simpler pattern
consistent with an equilibrium state. The implications for large-scale
regulation of the planetary dynamics are outlined.
