It is rare to see an extremely close-up view of our Sun, but this photo gives us a chance to look. This part of the sun is called the chromosphere, the second of the three layers of the star. You can see the dark sunspots, along with skinny threads and lighter regions called plains taken from the French word for beach. The sun goes out with them, while other times it's completely naked. Interestingly, the darker sunspots are much colder than the surroundings – they are formed because the magnetic fields are twisted over each other, essentially interrupting the flow of gas and leaving the region cooler.
A. de Burgos / ESA / ESAC / CESAR