illustration of Thomson scattering
<a class="external free" href="https://en.wikipedia.org/wiki/User:PAR">http://en.wikipedia.org/wiki/User:PAR</a>
2004-12-18
<a class="external free" href="https://en.wikipedia.org/wiki/File:Thomson_scattering_geometry.png">http://en.wikipedia.org/wiki/File:Thomson_scattering_geometry.png</a>