Observations by European Space Agency Cluster satellites have enabled scientists to confirm the existence and see for the first time in detail the "bow shock wave" where the sun's solar wind collides with the Earth's magnetosphere, which protects Earth from particles ejected from the sun.
ESA's four Cluster spacecraft, launched last year, are on a two-year mission to investigate a phenomenon in which solar winds can sometimes force energetic particles through the protective layer, causing aurorae and generating magnetic storms which can often disrupt communications.
The Cluster satellites made their first crossings of the magnetosphere last November. Data from the satellites shows that gusts in the solar wind cause the magnetosphere to expand and then decrease in size. These fluctuations mean that, for the first time, data was obtained simultaneously from both sides of the magnetosphere.
Source: Flight International
