Giant solar flare set to come back into view on the face of the Sun
The largest sunspot in 24 years, known as Active Region 12192, fascinated scientists as it rotated across the face of the Sun in late October (as shown in the time-lapse video above, courtesy of NASA's Solar Dynamics Observatory), before disappearing to the far side. Now it's making a return, its movements on the far side of the Sun mapped by the Joint Science Operations Center at Stanford University.
Sunspots are active areas on the Sun that form when magnetic field lines are warped. They look dark because they are cooler than the surrounding area.
The sunspot Active Region 12192 shot out four powerful solar flare and numerous smaller ones over the course of four days. The picture below shows the impressive display of coronal loops between 26 and 29 October.
Coronal loops are found around sunspots and in active regions and are associated with the closed magnetic field lines that connect magnetic regions on the solar surface. Energetic particles spinning along magnetic field lines make them visible to us.
Many coronal loops last for days or weeks, but most change quite rapidly.
However, Active Region 12192 was unusual as it did not shoot out huge bursts of plasma – called coronal mass ejections (CMEs) – as is more usual with sunspots.
CMEs that shoot out towards Earth cause geomagnetic storms that can interfere with satellites in orbit or even disable power grids on the surface.