Powered By Blogger

Wednesday, July 18, 2007

Understanding how explosions on the Sun affect the Earth

By Danielle Reeves

Scientists who study violent activity on our Sun are explaining how large explosions of particles from the Sun can affect satellites, space craft and even electrical power lines on Earth, at the Royal Society Summer Science Exhibition this week.

The exhibit explains what happens when an immense eruption known as a Coronal Mass Ejection (CME) happens on the Sun. CMEs are the largest explosions in the solar system and when they occur a mass of particles weighing roughly the same as Mount Everest is launched out into space. The exhibit was organised by scientists from Imperial College London, University College London, University of Wales, Aberystwyth, Armagh Observatory, University of Cambridge, Rutherford Appleton Laboratory and The University of Central Lancashire.

If a CME occurs in the direction of the Earth, the particles can cause significant problems to the electrical systems of spacecraft and satellites in orbit around the planet. Some CMEs have also been known to affect electrical power lines on Earth, and the highly energetic particles that are thrown out of the Sun could pose a radiation risk to astronauts in space, and even to passengers in aeroplanes that pass near the Earth’s poles.

The exhibit’s stand at the Royal Society will enable members of the public to talk to scientists involved in research to predict when CMEs are headed towards Earth. There will be 3D videos and posters describing the journey of a CME from its initiation on the Sun to its arrival at the Earth, and models of the satellites scientists use to observe them.

Dr Steve Bradshaw from Imperial’s Department of Physics, one of the scientists involved in the exhibition, explained: "Our best defence against CMEs is to have plenty of warning when one is heading towards the Earth, so that pre-emptive action can be taken to protect ourselves and the sensitive electronic equipment that we depend on."

Two solar observing missions were recently launched that should give scientists significantly more warning and time to be prepared than they have had in the past. The Hinode satellite will help solar physicists to better understand the physical processes taking place on the Sun that lead to CMEs, which will lead to more accurate forecasting of when a CME will erupt. The STEREO satellites will allow researchers to track CMEs in-flight between the Sun and the Earth, and by providing a stereoscopic view of their path through space - in the same way that our two eyes provide us with depth perception – the research team will be more quickly able to determine whether the CME is heading straight for us.

Dr Bradshaw added: "The Royal Society’s Summer Science Exhibition provides scientists with an ideal opportunity to talk to the public about their work. The research we’re doing on CMEs gives a new insight into some impressive explosions on our nearest star, which are fascinating for both scientists and the public to see, and I’m looking forward to sharing our discoveries this week."
Powered By Blogger