![]() It was borrowed directly from the Latin corōna, meaning “garland, wreath, crown.” Its plural form is corōnae. These findings are based on models that examine the 3D structure of plasma in the Sun’s corona and remind us that there is still much to discover about our Sun.Flowers and crows, priests and soldiers, suns and moons, kings and queens, lagers and viruses? What could all these disparate things possibly have in common? Well, in one way or another, they are involved in the rich history of the word corona.Ĭorona entered English around 1555–65. Instead, the more recent coronal veil hypothesis suggests that there are wrinkles or folds in sheets of plasma, much like you would observe in a piece of fabric. Because the Sun’s corona is thin and transparent, it is difficult to observe whether structures that overlap each other are actually looping or not. Instead, they might appear to loop due to an optical illusion. New research by NCAR’s High Altitude Observatory suggests that coronal loops actually may not be loops at all. Scientists have long thought that the strands of plasma extending above the Sun’s surface formed loops. Large coronal holes can cause geomagnetic storms to occur in Earth's magnetosphere and result in colorful displays of auroras in the skies near Earth's poles. This coronal hole is about 400,000 miles wide - more than 50 times as wide as Earth. ![]() The dark blue area covering almost the entire upper left quadrant of the Sun is a giant coronal hole, captured by NASA’s Solar Dynamics Laboratory in June 2013. Perhaps when a sunspot fades away, a coronal hole is left behind. Though scientists aren’t completely sure what causes coronal holes to form, there seems to be a connection between the location of sunspots on the solar surface and coronal holes in the Sun’s atmosphere. Coronal holes appear dark in X-ray and ultraviolet images of the Sun, but they are invisible to the eye. The plasma in these coronal hole regions is cooler and more dense than in other parts of the corona. Coronal holes are openings in the Sun’s magnetic field where streams of high-speed solar wind rush out of the solar atmosphere. Coronal loops are more common around solar maximum, when the Sun is most active and there are many sunspots.ĭuring solar minimum, when the Sun is least active, another feature of the corona is apparent - dark patches called coronal holes. Coronal loops often appear to arc between pairs of sunspots with opposite magnetic poles. The energy they give off is almost entirely ultraviolet rather than in the visible light spectrum, which means they can only be seen with the help of specialized equipment.Ĭoronal Loops, Coronal Holes, and SunspotsĬoronal loops are often associated with sunspots, which are places on the Sun's surface where powerful magnetic fields break through and extend up into the Sun's atmosphere. Some loops are extremely hot, having temperatures well above a million degrees. The electrified plasma flows along the curving lines of powerful magnetic fields, giving the coronal loops their characteristic shape.Ĭoronal loops can extend upwards many thousands of kilometers above the Sun’s surface. Hot, dense plasma causes these loops to glow. Plasma flows along closed magnetic field lines in the corona that pull it back toward the solar surface, forming structures that appear to loop.Ĭoronal loops are ropey, curving strands of plasma that appear as arcs above the Sun's surface.
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