19 Feb 2003

The show became even more spectacular in the early hours of 18 February 2003, when the Sun unleashed a storm of charged particles, known as a Coronal Mass Ejection (CME). It looked as if this ejection was heading for the comet. Astronomers are trying to find out if there was a head-on collision. The comet will remain in the LASCO field of view until Thursday 20 February 2003.

First recognised in the 1970s, CMEs play an important role in space weather. They occur when the magnetic field of the Sun whiplashes, sending a cloud of super-hot gaseous debris flying off into space. When a CME occurs very fast and powerfully and stretches out in the direction of our planet, it can cause a chain of effects. What can happen? The effects can affect satellites in orbit, burn out power station transformers on Earth, and endanger orbiting astronauts. Studying CMEs and their effects is an important goal for modern science.