Excellent question Bob -- A filter is used to produce the image. It's called an "Fe XII" filter, which stands for Iron-12. It's an expensive filter than only allows emission by iron-12 at 1,000,000 Kelvin (Fahrenheit or Celsius...it's all the same +/- 300 degrees) and iron-24 at 20,000,000 Kelvin through the filter.
nasa.gov
So for this filter, if it's not a specific wavelength from iron-12 and iron-24, then it gets blocked. A black region would just be a lack of iron-12 and iron-24 in the region.
These extremely high temperatures are only observed in the corona, which is considered the "atmosphere" of the sun. In this region, the iron molecules are trapped within the powerful magnetic fields of the sun and heated by constant bombardment of radiation (called coronal loops). Some of these loops get so energetic, they have enough power to break away from the sun, and the plasma (and hot iron with it) is emitted into space. Where the loop breaks into space, there is no iron-12 and iron-24 in the sun's corona, so the region looks black in the filter...called a coronal hole.
The iron-12 and iron-24 are being emitted into space and can hit Earth's magnetic field, causing it to wobble. This wobble, I theorize, impacts upper-atmosphere dynamics leading to changes in weather patterns on Earth of all time-scales (couple days to multi-decadal).
Stag notes the high-energy particles perhaps exaggerates people's mood, which leads to enhanced moves in the market. Dunno if I have that right, but it's kind of how I understand it. |
