MOTION MOUNTAIN

liquid electricity, invisible fields and maximum speed 63
600 km
EXOSPHERE
300 km
THERMOSPHERE
IONOSPHERE
F
85 km
45 km
12 km
MESOSPHERE
STRATOSPHERE
TROPOSPHERE
E
300
600 900 1200 1500
Temperature (K)
4
10
5
10
6
10
Electron density
(cm -3 )
F I G U R E 31 Top: the interaction of the solar wind and the Earth’s magnetic field. Centre: the magnetic
environment of the Earth. Bottom: the names of the layers around the Earth and a photograph of the
cold plasma, or magnetosphere, surrounding the Earth, taken in the extreme ultraviolet, and showing
both the ring at the basis of each aurora and a tail pointing towards the Sun (courtesy NASA).
The magnetic field of the Earth is clearly influenced by the Sun. Figure 31 shows the
details of how the stream of charged particles from the Sun, the solar wind, influences
the field lines and a several processes occurring in the higher atmosphere.The details of
these fascinating processes are still a subject of research.
∗∗
The names electrode, electrolyte, ion, anode and cathode were suggested by William
Whewell (b. 1794 Lancaster, d. 1866 Cambridge) on demand of Michael Faraday; Faraday
had no formal education and asked his friend Whewell to form two Greek words for
him. For anode and cathode, Whewell took words that literally mean ‘upward street’
and ‘downward street’. Faraday then popularized these terms, like the other wordsmentionedabove.
Motion Mountain – The Adventure of Physics copyright © Christoph Schiller June 1990–November 2015 free pdf file available at www.motionmountain.net