September 2011 was an active month for the Sun.
Active region number AR1302 unleashed two X-class flares as it appeared on the disk of the Sun, and seemed to be ready for more action. This sunspot was so large that 10 Earths could fit side by side across it.
These X-class solar flares caused great excitement amongst the solar scientists watching the Sun with spacecraft such as Hinode and the SDO.
Aurora created by an X-class Flare
Some of the solar flares had impressive coronal mass ejections (CMEs) associated with them, but these were not directed towards the Earth. However, the solar flares became increasingly more geoeffective as the sunspots turned toward Earth, causing spectacular aurorae and other less welcome effects.
Here is a photo of a spectactular aurora taken in September 2011 by Bjørn Jørgensen in the Lofoten Islands, North Norway.
The Sun has been relatively quiet in the past few years, leading some people to speculate that we were headed for another Maunder minimum, with very few sunspots. However, the Sun has well and truly woken up again now, and we can watch out for more action in the next few months and years as we head for solar maximum.
A movie of the aurorae filmed from the International Space Station (ISS) during September 2011.
Find out more about Hinode, SDO, solar flares, sunspots, coronal mass ejections, aurorae and the solar cycle in the Sun|trek website.