On October 9, the Sun had dramatic activity aimed right at Earth. Our star emitted an M1.6 class flare and a coronal mass ejection (CME). A deluge of fast electrically charged particles was flung at our planet, hitting it on October 12. Insights into the peculiar event have been reported by NASA.
These flares and CME can be dangerous but luckily this was not the case this time. The flare itself was several hundred times weaker than the most powerful one ever recorded, even weaker if we include the estimate for the 1859 "Carrington event" – the strongest geomagnetic storm in history. The event of this week led to an increase in auroral activity at the poles.
When CME particles interact with the Earth’s magnetic field, they are carried towards the poles. There they might end up slamming into the atmosphere, releasing light. These are the Northern and Southern Lights or Aurorae Borealis and Australis, respectively.
The activity across the night between October 11 and 12 was quite high so northern lights were visible as low as the north of England in Europe and the northern parts of Iowa and Nebraska in the US. In the southern hemisphere, Tasmania and the Southern Island of New Zealand/Aotearoa were the limit for visibility.
Higher latitudes appreciated the spectacle in full, with swirling aurorae dancing in the night skies of both hemispheres. Stunning images have been shared of the events of the last few days. Just check the Northern Light tag on Instagram to get an idea.
From space, the event was equally spectacular. NASA’s Solar Dynamics Observatory showed the flare being emitted right at us, flashing brightly and easily outshining the surrounding region. But the scale of the event is shown in its true greatness by another NASA mission. STEREO-A. This observatory is located further ahead on the Earth’s orbit so can look at the Sun from the side.
And on the observation from last week, it shows clearly the powerful CME being released towards our planet. NASA’s Moon to Mars Space Weather Operations Office estimate that at the point of release, the CME particles were traveling at approximately 983 kilometers per second (610 miles per second).