STEREO gives astronomers a first look at the space between the Earth and Sun

For the first time, an international team of astronomers have a side-on view as giant clouds of solar material leave the Sun and slam into the magnetic field of the Earth

On Tuesday 17 and Wednesday 18 April at the RAS National Astronomy Meeting in Preston, Professor Richard Harrison and Dr Chris Davis of the Rutherford Appleton Laboratory will present spectacular images and movies of these dramatic events taken by UK cameras mounted on the two STEREO spacecraft.

The two spacecraft that make up the NASA STEREO mission were launched last October. One probe is now travelling in an orbit ahead of the Earth while the other lags behind. Together the probes are imaging the Sun in 3D. They also have a unique perspective - they can view the space between the Sun and the Earth (the so-called Earth-Sun line), giving scientists their first views of this region of space.

The Rutherford Appleton Laboratory (RAL) in Oxfordshire and the University of Birmingham led an international effort to develop two identical Heliospheric Imager (HI) instruments. One HI is mounted on each of the two spacecraft so astronomers can watch the Earth-Sun line. In particular, this view gives scientists a ringside seat when giant clouds of material (Coronal Mass Ejections or CMEs) travel from the Sun to the Earth.

CMEs can be made up of more than 1000 million tonnes of charged particles and travel at up to 1000 km per second. When a CME reaches the Earth it can have dramatic effects; compressing the terrestrial magnetic field, generating displays of the northern lights, disrupting radio communications, overloading power grids and damaging satellites.

The ability to track CMEs as they leave the Sun, to understand how they propagate and evolve and to predict their arrival at Earth are all goals of the unique HI system. As the STEREO spacecraft move into their orbits over the coming months we will see increasingly better views of the 3D Sun and the passage of Earth-directed clouds in space. However, the UK HI instruments have now made their first observations of CMEs in the inner solar system, showing spectacular images of these clouds and demonstrating that the instruments are operating flawlessly.

UK participation in STEREO is funded by the Science and Technology Facilities Council which also operates the Rutherford Appleton Laboratory.

Contact Information

• RAS Press Office
  Robert Massey
  Tel: +44 (0)20 7734 4582
  Mobile: +44 (0)794 124 8035
  
  
• Anita Heward
  Tel: +44 (0)1483 420 904
  Mobile: +44 (0)7756 034 243
  
  
• National Astronomy Meeting Press Room (16 - 20 April only)
  Tel: +44 (0)1772 892 613
  
  
• Professor Richard Harrison
  Rutherford Appleton Laboratory
  HI/STEREO Principal Investigator
  Tel: +44 (0)1235 446884
  Mob: +44 (0)7876 582 776
  
  
• Dr Chris Davis
  Rutherford Appleton Laboratory
  HI/STEREO Project Scientist
  Tel: +44 (0)1235 446710
  
  

From 16-20 April, the STEREO team can be contacted via the RAS press office (details above).

Notes for Editors

The 2007 RAS National Astronomy Meeting is hosted by the University of Central Lancashire. It is sponsored by the Royal Astronomical Society and the Science and Technology Facilities Council.

This year the NAM is being held together with the UK Solar Physics (UKSP) and Magnetosphere, Ionosphere and Solar-Terrestrial (MIST) spring meetings. 2007 is International Heliophysical Year.

STEREO is a NASA-led mission, with major contributions from European countries including the UK.

Images and Movies

The HI images will be posted on the RAS NAM website (link opens in a new window)| at www.nam2007.uclan.ac.uk/press.php and also on the RAL STEREO website (link opens in a new window)|.

Image caption: A solar mass ejection viewed in the inner solar system from one of the UK HI instruments on STEREO. The Sun is off the right hand side and the Earth is off the left hand side of the image. We see a background of stars as well as the two inner planets (the brightest objects in the frame) Venus (left) and Mercury (right). The cloud of solar material can be seen entering the frame from the right, setting off on its journey from the Sun to the Earth.

View further images and animations of Coronal Mass Ejections (link opens in a new window)|.

View further images of and from the STEREO spacecraft (link opens in a new window)|.

Royal Astronomical Society website (link opens in a new window) |.

RAS National Astronomy Meeting website (link opens in a new window).