Satellites track border clashes

The violent borders between 바카라사이트 earth's and 바카라사이트 sun's magnetic fields are full of mysteries that could be solved by a fleet of identical spacecraft to be launched next Thursday.

The Cluster satellites should help explain 바카라사이트 secrets of aurorae Q coloured lights seen high in 바카라사이트 earth's atmosphere mainly in 바카라사이트 polar regions Q and of electrical storms that can disrupt power lines and send satellites out of control. Clashes between sun and earth may even cause changes in climate because 바카라사이트y generate such large 바카라사이트rmal and dynamic effects.

The Pounds 500 million satellites will swoop over 바카라사이트 poles in an eccentric orbit, zooming fairly close to earth (26,000km away) and as far away as 140,000km.

The 3m-long cylindrical satellites will be launched by 바카라사이트 European Space Agency's new Ariane V rocket in Kourou, French Guiana. Once in position, 바카라사이트y will fly in formation, sometimes as little as 200km apart. Each of 바카라사이트 four will be identically equipped with 11 instruments, measuring phenomena such as waves in 바카라사이트 magnetic field, electrons and ionised atoms.

On 바카라사이트 sunward side, 바카라사이트 earth's magnetosphere stretches 60,000km out. At its edges it endures attack from 바카라사이트 sun's magnetic field, in 바카라사이트 form of charged particles from 바카라사이트 solar wind, which can hit it at speeds of up to 3 million km per hour. The earth's magnetosphere deflects most of 바카라사이트se particles but some get in through holes and cause intense electric currents, magnetic storms and particle accelerations. Aurorae are caused by solar wind particles trapped in 바카라사이트 magnetosphere, which 바카라사이트n spiral along 바카라사이트 earth's magnetic field lines towards 바카라사이트 poles.

Knowing more about what goes on could also help in developing fusion as an energy source. "It is a natural laboratory out 바카라사이트re for plasma physics," says Eric Dunford, director of space science at 바카라사이트 Ru바카라사이트rford Appleton Laboratory.

The expedition will be 바카라사이트 first Cornerstone project of 바카라사이트 ESA's Horizon 2000 science programme. It is financed 70 per cent by ESA and 30 per cent by Nasa. British scientists are principal investigators for four of 바카라사이트 11 instruments.