The Naked Scientists-June 2012

The final lecture of the day was given by Dr Jim Wild from Lancaster University and Dr Chris Davis from STFC Rutherford Appleton Laboratory on space weather.


Jim explained the physics of the aurora borealis and why the Earth’s magnetosphere is so important to our survival and Chris talked about Solarwatch and how he is keeping track of the Sun’s activity.

Chris started the lecture by explaining that during a Coronal Mass ejection the Sun ejects a billion tonnes of stuff at a million mph.

SOHO, the Solar & Heliospheric Observatory, is a project of international collaboration between ESA and NASAto study the Sun from its deep core to the outer corona and the solar wind.

SOHO was launched on December 2, 1995. The SOHO spacecraft was built in Europe by an industry team led by prime contractor Matra Marconi Space (now EADS Astrium) under overall management by ESA. The twelve instruments on board SOHO were provided by European and American scientists. Nine of the international instrument consortia are led by European Principal Investigators (PI’s), three by PI’s from the US. Large engineering teams and more than 200 co-investigators from many institutions supported the PI’s in the development of the instruments and in the preparation of their operations and data analysis. NASA was responsible for the launch and is now responsible for mission operations. Large radio dishes around the world which form NASA’s Deep Space Network are used for data downlink and commanding. Mission control is based at Goddard Space Flight Center in Maryland. Part of SOHO’s job is to investigate the solar wind and coronal mass ejections (CMEs). Earth directed CMEs are observed near the Earth.

STEREO mission (heliospheric imager) consists of two space-based observatories – one ahead of the Earth in its orbit and the other trailing behind. With this new pair of viewpoints, scientists will be able to see the structure and evolution of solar storms as they blast from the Sun and move out through space.

Jim Wild continued the lecture. The Northern lights are a consequence of the electromagnetic connection to our Sun. The magnetized solar wind is a hot energetic plasma (a charged gas). Charges always respond to electromagnetic fields. The Earth’s magnetosphere protects us (it is also home to a family of charged particles). The colours are a consequence of excitation such as the two stage excitation of oxygen. The light is emitted when the electrons drop back to a lower energy level. E = hf where E is the energy of the light photons, h is Planck’s constant and f is the frequency of the light.

Finding auroras around exoplanets may be a sign that life is present on them. You can “like” aurorawatch on facebook.

A fluctuating electrojet can produce 10E6A. A time varying magnetic field at ground level and an electric field can be induced in the Earth’s crust.


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