On Wednesday the 17th July Dr Colin Forsyth from the Mullard Space Research Centre gave a presentation on how radiation from the Sun affects the way Radio Waves move around the Earth. He started by explaining the different states of matter and how they react when subjected to varying degrees of heat. This was followed by an explanation of how the Suns surface is made up along with the magnetic fields and how they interact with one another. When the Sun ejects masses of plasma, CMEs (Coronal Mass Ejections), these interact with the magnetic fields and behave in different ways with some plasma going back to the surface and some into space depending on the strength of the ejection.
Colin then explained how the Earths magnetic field is made up and showed many illustrations to highlight how this changes through time. This was enhanced by an explanation of how a CME when impacting the Earths magnetic field is not able to get to us on the surface because of the protection our magnetic field gives us. However it does affect the upper layers of our atmosphere by changing the way that Radio Waves are able to reflect/refract off the ionosphere and thereby changing the distance that we are able to communicate.
All sorts of other effects take place such as where the magnetic fields join at the poles the particles of plasma are able to react with the gasses in the lower atmosphere, they slow down and become visible as the Northern and Southern Lights. Obviously there was more detailed information given and is not covered by this brief report.
Suffice to say that it was an interesting evening with many questions from those that attended. The meeting had to be held alfresco because Hut 18 had an infestation of what turned out to be Bees.
BrianG
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