By Dr David Whitehouse BBC News Online science editor

It occurred at 1319 GMT on Monday and was imaged by the Solar and Heliospheric Observatory, which sits in space at a gravitational balance point between our star and Earth.

The giant prominence at the bottom left of the image is more than 30 times the Earth's diameter. Such prominences are not uncommon on our star.

If they are directed towards the Earth, they can lead to dramatic lights in Northern and Southern polar skies and also radio and communications interference. Researchers say that this particular explosion was directed away from Earth.

Hot but faded

The prominences are gigantic loops of magnetic fields that emerge from below the Sun's surface. As they rise, they become filled with trapped, superhot gas that is heated to many millions of degrees.

Soho is a US/European satellite designed to study the Sun

Sometimes, as the magnetic fields become twisted and unstable, the magnetic energy collapses and explosively heats vast quantities of gas which then bursts and rises off the Sun in just a few minutes or hours.

The image taken by the Soho satellite is in the spectral line of singly ionised helium (He II) in the extreme ultraviolet region of the spectrum.

The material in the eruptive prominence is at temperatures of 60,000-80,000 Kelvin, which although extremely hot is still much cooler than the surrounding corona, or outer atmosphere, which is typically at temperatures above one million K.

Researchers followed the eruption as it moved out in space and faded.