A year of examining the Sun-Earth relationship starts *First Images of a CME from STEREO’s HI cameras*

The initiative started with an event at the United Nations in Vienna. The Sun produces the solar wind – a stream of charged particles that blows across the planets of the solar system, including the Earth. Whilst the Earth’s magnetic field protects us from most of the effects of the solar wind, we still experience the consequences of massive events on the Sun, both as a threat to satellites and power systems and as the beautiful aurora seen at the poles.

International Heliophysical Year (IHY) is a multinational coordination effort both to raise awareness of the relationship between the Sun and the Earth and also to drive a programme of collaborative scientific research in this important field. The UK was one of the founding countries of IHY, and the science programme is being coordinated from the CCLRC Rutherford Appleton Laboratory in the UK.

To mark the launch of International Heliophysical Year, scientists have released the first dramatic images of a Coronal Mass Ejection taken with the UK-built HI cameras on the STEREO mission. Prof. Richard Harrison of the Rutherford Appleton Laboratory, Principal Investigator for the HI cameras and one of the original proposers of IHY said: “It is wonderful for the UK that we are able to deliver these first dramatic pictures right at the start of IHY”.

Dr Lucie Green of UCL’s Mullard Space Science Laboratory is outreach co-ordinator for IHY in the UK. She explains “Many people imagine the Sun to be a docile disc in the sky. In reality it is a seething fireball of high-energy explosions. Sometimes these explosions throw off huge clouds of debris, known as Coronal Mass Ejections (CMEs). These can be ejected in any direction, but some come directly towards the Earth, posing a threat to astronauts, satellites and even ground-based electricity distribution systems. The more we understand about the way the Sun relates to its environment, the better we can protect humanity from this ‘space weather’.”

Professor Keith Mason, Chief Executive of the Particle Physics and Astronomy Research Council said “2007 will be a significant year in developing our understanding of the Sun-Earth relationship. We will learn a great deal about the Sun from the recently launched Hinode and STEREO spacecraft and co-ordinate those results with what we see closer to home, with for example the 4 Cluster satellites studying the upper atmosphere and the EISCAT ground radar in Svalbard.”

NASA’s STEREO mission is starting to return data on the Sun and in the coming months will release unique panoramic views from the Sun to Earth as well as the first 3D images of the Sun ever. Today, scientists provided a teaser of what is to come, with pictures of a CME that erupted on 24th January 2007.

Another mission that will provide new data this year is NASA’s THEMIS mission to study the Aurora, successfully launched late on Friday 16th February.

During IHY scientists aim to use observations taken with Hinode and STEREO to learn more about CMEs. A new tool will be developed at the CCLRC Rutherford Appleton Laboratory that will allow the prediction of CMEs that are Earth directed. These CMEs are then tracked along their journey to the Earth using the STEREO spacecraft. The tool identifies regions that have dimmed as a result of the expelled material.

Website

As part of IHY a new website is being launched that will draw together information on the UK’s research in this area in one place. The website will also have a special section containing Educational materials in the form of fact sheets, contacts and activity ideas. The activities aim to show students the science of the Sun-Earth connection and put across the knowledge that the Earth isn't an isolated object. Students will be able to look at real data and act out the role of scientist. The activities are about the science but they are also about how science is done.

Dr Jim Wild, the website co-ordinator from Lancaster University said: “Whether using satellites to study the heart of the sun or the sizzling radiation found in Saturn's magnetic field or ground-based cameras and radars to probe the northern lights high over the arctic circle, UK scientists are at the forefront of solar, solar-terrestrial and solar planetary science. The sunearthplan.net website will showcase this exciting science and provide a forum for visitors to directly question the scientists directly.”