On April 17, 2016, an active region on the Sun released an M6.7 class solar flare, captured here by NASA’s Solar Dynamics Observatory (SDO).
Solar flares are powerful outbursts of electromagnetic radiation from the Sun lasting from minutes to hours.
Harmful radiation from a flare cannot pass through the atmosphere of Earth to affect humans on the ground. However, when intense enough, they can disturb the atmosphere in the layer where GPS and communications signals travel.
Solar astronomers classify flares according to their brightness in the X-ray wavelengths. There are three categories: C, M, and X.
The April 17 event is classified as an M6.7 class flare (the number provides more information about its strength; an M2 is twice as intense as an M1, an M5 is five times as intense).
M-class flares are medium-sized; they generally cause brief radio blackouts that affect polar regions; minor radiation storms sometimes follow M-class flares.
NASA’s SDO spacecraft captured this image of an M6.7 class solar flare on April 17, 2016. Image credit: NASA’s Goddard Space Flight Center / SDO / Genna Duberstein.
According to NOAA’s Space Weather Prediction Center, the April 17 flare caused moderate radio blackouts.
The flare came from an area of complex magnetic activity on the Sun – known as an active region, and in this case labeled Active Region 2529 – which has sported a large sunspot over the past several days.
This sunspot has changed shape and size as it slowly made its way across the Sun’s face over the past week and half.
For much of that time, it was big enough to be visible from the ground without magnification and is currently large enough that almost five Earths could fit inside.
The newly-released 4K movie was captured in several wavelengths of extreme UV light, a type of light that is typically invisible to our eyes, but is color-coded in SDO images for easy viewing.
