Le nouveau Cherche et trouve de Little Urban, aussi coloré, déjanté et diablement amusant que le premier (A la recherche de la Carotte bleue), en très très grand format pour le plaisir de tout-petits !!! (Et des plus grands, qui trouvera en premier ?)
We are now in the years of maximum solar activity. Spectacular outbursts of particles and fields will bombard the Earth and continue at high levels for the first few years of the millennium. In this period of striking auroras and satellite-damaging magnetic storms, it is natural to wonder about the magnetic fields that guide solar particles to create such astonishing displays. This book takes the reader on a tour through the Earth's magnetic fields with a minimum of jargon and mathematical detail. Journey with the author from historical observations of the magnetic field and magnetic applications in the modern world through the Earth's principle magnetic field to understand why there are so many magnetic pole locations. The everyday main field and quiet-time variations that are superimposed on the main field together form a baseline from which we measure the magnificent but potentially damaging magnetic storms. Learn how these spectacular field disturbances start from blasts of particles ejected from our Sun.
Wallace Hall Campbell is guest scientist at the Solar-Terrestrial Physics Division of the National Oceanic and Atmospheric Administration in Boulder, Colorado. His current appointment follows a distinguished career as a research geophysicist within the geomagnetism group at the USGS and many years of upper atmosphere research in geomagnetism for NOAA. His research interests continue to be ionospheric currents, electrical conductivity of the Earth, geomagnetic storms, pulsations, and field applications. Dr Campbell wrote and co-authored two major textbooks and more than a hundred publications in geomagnetism.