A powerful blast of plasma erupts from the Sun, like a dragon breathing fire, in this colorized view of a ‘coronal mass ejection’. Image © SOHO (ESA/NASA)/S. Hill
These huge clouds of magnetised plasma are ejected from the Sun’s atmosphere – the corona – and launched into interplanetary space. Millions of tonnes of gas race away from the Sun at several million kilometres per hour.
This image shows an event observed by the SOHO satellite on 4 January 2002, coloured to indicate the intensity of the matter being ejected by the Sun. White represents the greatest intensity, red/orange somewhat less, and blue the least.
An extreme-ultraviolet view is superimposed to show the size and active regions of the Sun that day.
The shaded blue disc surrounding the Sun at the centre of the image deliberately blots out direct sunlight to allow study of the details in the corona.
When ejections like this hit planet Earth, spectacular natural light displays – aurora – can be triggered over the poles. In the most extreme events, they can lead to geomagnetic storms that can result in regional power outages and communications blackouts.