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Clúster celebra su primera década de descubrimientos   Artist's impression of the four Cluster spacecraft flying in formation.  Scientists have found that extreme solar activity drastically compresses the magnetosphere and modifies the composition of ions in the near-Earth environment. They are now challenged to model how these changes affect orbiting satellites, including the GPS system. Under normal solar conditions, satellites orbit within the magnetosphere — the protective magnetic bubble carved out by Earth’s magnetic field. But when solar activity increases, the picture changes significantly: the magnetosphere gets compressed and particles get energized, exposing satellites to higher doses of radiation that can perturb signal reception. This is why monitoring and forecasting its impact on near-Earth space is becoming increasingly critical to safeguard daily life on Earth. One way to do this is by studying the physics of near-Earth space and observing the impact of such activity in time.  This artist's impression shows the four Cluster spacecraft encompassing a 'magnetic null' region. A magnetic null region is a three dimensional zone where the magnetic fields break and reconnect. Before ESA's Cluster started exploring the Earth's magnetosphere it was not possible to identify any of such regions, as the detection required at least four simultaneous points of measurements.
Cluster measurements made on 15 September 2001 showed that the null point exists in an unexpected vortex structure about 500 kilometres across, a characteristic size never been reported before in observations, theory or simulations. Release date: 21 julio 2010 |