In the giant system that connects Earth to the sun, one key
event happens over and over: solar material streams toward Earth and the giant
magnetic bubble around Earth, the magnetosphere helps keep it at bay. The
parameters, however, change: The particles streaming in could be from the
constant solar wind, or perhaps from a giant cloud erupting off the sun called
a coronal mass ejection, or CME. Sometimes the configuration is such that the
magnetosphere blocks almost all the material, other times the connection is
long and strong, allowing much material in. Understanding just what
circumstances lead to what results is a key part of protecting our orbiting
spacecraft from the effects of such space weather.