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What's up with that huge dark hole in the Sun?

ImaGeo iconImaGeo
By Tom Yulsman
Jul 11, 2016 7:48 PMNov 20, 2019 1:29 AM


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Not to worry, everything's under control

An animation of images of the Sun acquired by NASA's Solar Dynamics Observatory spacecraft on July 11, 2016 highlights a dark area, called a "coronal hole," covering the top of the Sun. In the animation, the Sun is seen in extreme ultraviolet light. This highlights the atmosphere —the Sun's corona. Hot, active regions are bright. The dark coronal hole is an area where very little radiation is being emitted. (Source: NASA Solar Dynamics Observatory) Every once in awhile, the Sun develops a huge "hole" — a dark patch in its outer atmosphere, or corona, like the one visible above. This is the Sun, as seen today by NASA's Solar Dynamics Observatory. I've posted about these coronal holes before, but I really like this animation, as well as the one below offering a visualization of what's actually going on.


A coronal hole is a place where where the Sun's magnetic field opens out into interplanetary space, allowing hot material from the corona to speed outward. As a result, these areas have very little hot plasma compared to their hotter, brighter surroundings. So they appear much darker.

The Sun blows its top — again

This video clip shows the Sun as seen by the Solar Dynamics Observatory spacecraft on June16, 2016. A map of the Sun's magnetic field is overlaid on the SDO video. In the animation above, acquired by the SDO spacecraft on June 16th, the Sun is once again seen in extreme ultraviolet light, highlighting the corona. A coronal hole is evident here too. This animation also adds a map of the Sun's magnetic field lines. Those lines are tightly bundled near the brighter active regions in the corona. Here, the Sun's magnetic field is particularly intense. Meanwhile, the magnetic lines from the coronal hole clearly open out into space, allowing hot particles to stream outward. The result: a relatively cool, dark "hole."

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