This very cool movie (click on the picture to watch the movie) shows the space environment in the Sun’s neighbourhood. The coronagraph LASCO onboard the spacecraft SOHO recorded it. The black disk occults the Sun such that the direct overwhelming light is blocked, it is simply an artificial solar eclipse. The white moving features are plasma clouds ejected from the Sun: Coronal Mass Ejections or CMEs. The coloured arcs indicate how wide and how fast those CMEs are. The left movie is made in visible light (the red is artificial - space doesn’t look red), the right movie is a difference movie in which two images are subtracted such that you see the difference between the two images. In this way, plasma clouds that look faint in the red movie are better seen.
On September 2, a cloud moving to the right is visible. A shock in front of the cloud (similar like what happens with a speed boat) accelerated electrons such that they started to emit radio waves. These waves were recorded by our radio instruments in Humain, Belgium and are seen as a bright blob in the Frequency-Time graph (below). When we see a blob like this, we immediately check the solar environment for clouds.
The Sun continued on this rhythm. On September 4, a really fat cloud was seen in the red and grey movie. At a certain point, the cloud even seems to enfold the entire black disk. This is what we call a halo CME. It is a cloud that moves along the Sun-Earth line. And this one is heading into the direction of the Earth and will bump on the Earth’s magnetic field one of these days. Fasten your seat belt!
Stay tuned and check the alerts of our Space Weather forecast centre: http://sidc.be
