Scientists finally uncover the source of the Sun’s ghost-like shadows

Fareeha Arshad
Photo by NASA on Unsplash

The mysterious shadows present in the Sun’s atmosphere that appear during the solar flares and has a dark curtain-like appearance have been a source of attraction for scientists for a long time. Scientists have been finally able to uncover the basis of these shadows, called the ‘downward-travelling dark voids’ that surround the Sun and were first noticed in 1999. These shadows were assumed to be related to magnetic field interactions that cause solar eruptions. However, a new study published in Nature Astronomy hints that these ‘supra-arcade downflows’ happen because of fluid interactions in Sun’s plasma.

The Sun is made up of hot plasma that rapidly interacts with electromagnetic forces. In addition, the Sun’s spherical shape causes the rotation of the equatorial surface to be more rapid than the poles causing the solar magnetic field to become more twisted. This results in the production of enhanced localized magnetic field all around the Sun’s surface, causing the flares as we see. Sometimes, these magnetic fields become intertwined, causing the roots of solar flare to disconnect and reconnect. At the same time, the electric power current also flows over the flare surface, causing a large amount of energy.

These supra arcade downflows appear similar to reconnection outflows observed in magnetohydrodynamics; however, they are over 15% slower than simulated outflows – a dilemma the researchers tried to understand for a long time. This complexity is now being studied by the Harvard and Smithsonian Center for Astrophysics researchers analyzing the downflows data from the Solar Dynamics Observatory of NASA. So far, they have concluded that the interface region of the solar surface is perhaps more complex than previously assumed. Therefore, further studies are needed to understand better the phenomenon’s complexity, especially the magnetic energy released during solar flares.

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I am a scientist by profession and a historian by passion. I write about current affairs, history, science, and lifestyle.

Texas State

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