IRIS Movie of the Day
At least once a week a movie of the Sun taken by NASA's Interface Region Imaging Spectrograph (IRIS) is posted by one of the scientists operating the instrument.
Formation of a solar prominence
Credit: IRIS, LMSAL/NASA, Gosic Milan
On 6-May-2018 IRIS captured a prominence at the solar limb. Prominences represent cool gas located at coronal heights. They are about 100 times cooler, but also about 100 times denser than the surrounding million Kelvin hot coronal plasma. Since we cannot predict where prominences will appear, this movie gives us a quite rare opportunity to see how prominences are formed. Around the prominence we can also see some loop-like structures representing plasma that is rapidly cooled from millions down to a few tens of thousands of Kelvins (coronal rain). Bright pixels that stands out clearly at the end of the movie are not caused by solar radiation but happen whenever high energy particles hit our CCD camera when IRIS is passing through the Earth's radiation belts.