Space and PhysicsAstronomy

One Of The Sun’s Most Famous Features Might Be An Illusion


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockMar 28 2022, 17:32 UTC
Coronal loops

Coronal loops are very visible in this image taken by the Solar Dynamic Observatory on March 28. Image Credit: NASA/SDO via Atmospheric Imaging Assembly

The Sun’s Coronal loops are one of the most spectacular features we can observe on our star. Thin strands of extremely hot plasma rise from the surface of the Sun, into the solar upper atmosphere: the corona. A new study now has a radical suggestion. Not all those structures are there and what we see is a trick of the light.


In a paper published in The Astrophysical Journal, Dr Anna Malanushenko and her team reported the peculiar findings of a simulation of the Sun. Computer models are often used to study what we can’t explore firsthand, and the simulation employed has been used in the past to explain several solar features by recreating them successfully.

The team didn’t expect to find anything unusual in looking at coronal loops. Observations in ultraviolet light have shown these bright arcs of material in so many pictures, and theories have suggested that they are thin, long, magnetized tubes of plasma creating bright loops. The simulation creates images filled with these thin structures, but once the team looked at them in 3D, the whole perspective changed.

Most of the strands are not there, even though when looking at the system in two dimensions they appear to be so. They are created by the overlapping intensity of plasma not confined in thin tubes, but diffused in a vast and more spread-out structure, just like a veil. Not every loop is like that but any loop could be.

Malanushenko loop versus veils
Dark lines appear projected in the shadow both in the solid loops and veil-wrinkle approach, but three-dimensionally we know that the two setups are wildly different. Image Credit: Malanushenko with permission.

“The take-home message of the paper is not that every coronal loop is a wrinkle in a veil. The implication is that each one of them could be a veil and we would not know,” Malanushenko, who’s a scientist at the National Center for Atmospheric Research High Altitude Observatory, told IFLScience. “The coronal veil hypothesis is important because we need to measure the solar corona differently.”


So how could these observations take place? Malanushenko explains that this is far from easy. Her group is working on a statistical approach that might be able to reveal if we are looking at a veil or individual strands, but it is early days. And she thinks that other researchers might have other approaches to confirm or disprove this hypothesis.

“I’d like to initiate a discussion in the community on how to best approach this because this is bigger than a topic for just one group,” Malanushenko told IFLScience.

Malanushenko has spent her entire career studying coronal loops so the findings of the simulation – that they might not be what we thought – created some strong emotions.


“I’m both depressed and excited. I’m depressed because this concept may impact an unknown number of previous studies in unknown ways. I’m also excited because it means we will have to develop some new techniques, and whenever we do that there can be a breakthrough in how we understand the Sun,” Malanushenko told IFLScience.

“I’m very excited to see what will happen!”

Space and PhysicsAstronomy
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