Coronal hole

Coronal holes are part of the Sun's corona and are constantly changing and reshaping because the corona is not uniform. Coronal holes are areas where the Sun's corona is darker, and colder, and has lower-density plasma than average because there is lower energy and gas levels. The sun contains magnetic fields that arch away from areas in the corona that are very thin due to the lower levels of energy and gas, which cause coronal holes to appear when they do not fall back. Thus, solar particles or solar wind escape and create a lower density and lower temperature in that area. The aurora borealis that is seen at the northern and southern poles are the result of solar wind entering the Earth’s atmosphere.

First Discoveries

In the 1960s, the Sydney Chris Cross radio telescope took x-ray images, although it was unclear what they were. Some research also points out that coronal holes were first spotted in the early 1970s. These were found when X-ray telescopes in the Skylab mission were flown above the Earth's atmosphere to reveal the structure of the corona.