Sun Tans, Fission and Fusion - More about this podcast

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STEREO spacecraft A |
At school they teach us that energy cannot be made or destroyed and that all energy comes from the sun. The power of the sun however, is even huger than its magnificent size of …
The Sun is not fully understood and the more we learn about, it the more we can do with its power - the relationship between the sun and plants is well understood and as is the process by which the sun gives energy. The power of the sun has already been used for a variety of things; from solar powered calculators to providing electricity to homes. On this week's show we will have Davis explaining how he hopes to learn more about the Sun, Lewins talking about how he plans to use the Suns energy and X describing the effects of too much Sun on people who have been basking in its glow a little too long.
The Solar TErrestrial RElations Observatory (or STEREO to its pals) is the third mission in NASA's Solar Terrestrial Probes Programme (STP). This two year mission will provide a new view of the Earth-Sun system. It involves two almost identical observatories (one is shown in figure 1); one ahead of Earth in its orbit and one trailing behind, they will trace the flow of energy and matter from the Sun to Earth as well as reveal the 3D structure of Coronal Mass Ejections (more about these later) and why they happen. STEREO will also provide alerts for Earth-directed solar ejections, from its unique side-viewing perspective adding it to the fleet of Space Weather detection satellites.
So we does Earth need STEREO? Well coronal mass ejections (or CMEs to their enemies - as shown in figure 2) are powerful eruptions that can blow up to 10 billion tons of the Sun's atmosphere into interplanetary space. They are erupted at speeds of around one million miles per hour and can create major disturbances in the interplanetary medium and trigger severe magnetic storms when they collide with Earth's magnetosphere. Large geomagnetic storms can damage or destroy satellites and pose a serious threat to astronauts when outside of the protection of the Space Shuttle or the International Space Station and have been known to cause electrical power outages.
Solar ejections are the most powerful drivers of the Sun-Earth connection. Despite their importance little is known about their origin or evolution - STEREO which will be able to take stereoscopic (3D) images of the structure of CMEs will enable scientists to learn more about this.
The UK's involvement in this project is through the Heliospheric Imager (affectionally known as HI) which is just one of the instruments on board the space craft. Chris Davis will be on the show to talk about his involvement in HI at the Rutherford Appleton Laboratory and will be talking about the Sun's 11 year activity cycle and CMEs. The Laboratory has provided the detectors for all of the cameras onboard the STEREO spacecraft and is leading the scientific management of the HI instruments. The two instruments were built in the UK by a team at the University of Birmingham led by Dr Chris Eyles. Each HI consists of two wide-field white light cameras housed in a carbon fibre box around 70cm long. The combined field of view of these cameras is 90o the instruments are positioned facing Earth on the side of each of the STEREO spacecraft; so that their field-of-view spans from just off the limb of the Sun to beyond the orbit of the Earth. As a result, they will be able to detect any CMEs heading towards the Earth.
The UK has a world-leading reputation in the field of solar science and the Rutherford Appleton Laboratory is working with UK universities to fully exploit data from the STEREO mission especially the HIs. Understanding CMEs is the primary goal, however, two wide-field cameras in space represent a fantastic opportunity tostudy a wide variety of objects. UK academics have come up with proposals to use HI data to investigate many of these - from comets to extra solar planets.
So when does it all blast off? Well currently NASA are saying no earlier than the 30th July, you can keep up to date with the mission by logging on to their website and following links to STEREO via the missions page.
Right, that's the space mission, but what else is on the show? As mentioned earlier Dr Jeffrey Lewins of Cambridge University will be talking about thermodynamics and his work with nuclear power. He has worked for fusion programme at Culham and was President of the Institute of Nuclear Engineers. He will be talking about his work which involves the applied mathematics of fission reaction calculations and his interest in comparing the practicalities of producing electricity from either nuclear fission or nuclear fusion.
Finally Dr Anna Nicolaou from the University of Bradford; will be explaining the science of sunburn - the difference between UVA and UVB radiation, why some people tan easily whilst others do not and possible future sunburn protection.