ESA's mission Cluster consists of four identical spacecraft flying in formation between 19 000 and 119 000 km above the Earth. They study the interaction between the solar wind and Earth’s magnetosphere, or the Sun-Earth connection in 3D.


 
Earth's chirps and whistles, click on the top right to listen.


 
Animation depicting the four Cluster satellites as Auroral Kilometric Radiation (AKR) washed over them. AKR is generated high above the Earth, by the same shaft of solar particles that then causes an aurora to light the sky beneath.

By analysing 12 000 separate bursts of AKR recorded by Cluster, a team of astronomers have determined that the AKR is beamed into space in a narrow plane. For each of the AKR bursts analysed, astronomers pinpointed its point of origin to regions in Earth’s magnetic field just a few tens of kilometres in size. These were located a few thousand kilometres above where the light of the aurora is formed.

This was only possible because of the Cluster constellation's four spacecraft flying in formation that could be used to locate the points of origin by triangulation.



Release date: 30 August 2010