Hidden secret of the Sun finally revealed

Scientists discover high-frequency magnetic waves as the possible cause behind the Sun's mysterious corona heating, revealing a long-standing solar secret.

| Updated on: Jul 27 2023, 09:44 IST
Solar storms that plagued the Earth this week: Massive solar flare eruption, 2 CME strikes, more
Solar Flare
1/5 The week began with a minor solar storm incident on Monday, when aurora displays were seen in some high-latitude areas. The solar activity didn't stop there as another new sunspot, AR3363, that appeared to be crackling with solar flares also began moving towards Earth's view. (Pixabay)
Solar Flare
2/5 The very next day, the unstable region on Sun began exploding. NASA's Solar Dynamics Observatory detected a massive M6-class solar flare that kept erupting for a long duration. Reportedly, it released more energy than some X-class flares. This sparked a planet-wide shortwave radio blackout. (Pixabay)
Solar Flare
3/5 On Wednesday, the National Oceanic and Atmospheric Administration (NOAA) prediction models confirmed that a fast-moving coronal mass ejection (CME) released during the flare eruption, and it was set to deliver a glancing blow to the Earth.  (NASA)
Solar Flare
4/5 NOAA declared a 3-day warning for solar storms as it confirmed that yet another CME cloud is also headed for our planet and can impact the magnetosphere on July 22. The first CME was expected to strike on Friday, July 21. (NASA SDO)
Solar Flare
5/5 On Friday, the first of two CME struck the Earth, delivering the second minor solar storm for the week. The second CME was expected to strike by July 22 and intensify the first ongoing storm. The resultant effect has been forecasted to even spark a G3-class geomagnetic storm. Now, the weekend appears to be a quiet one, as no further solar activity is expected. But with multiple new sunspots expected to come to the Earth's view over the weekend, the next week can be even more chaotic. (Pixabay)
Solar Flare
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Mystery solved: High-frequency waves heat Sun's corona, say scientists. (NASA)

Scientists at the Royal Observatory of Belgium (ROB) and KU Leuven have achieved a momentous breakthrough, potentially resolving one of the most enigmatic puzzles of our solar system: why is the Sun's corona hotter than its surface?

The Sun's corona exhibits a temperature approximately 200 times higher than the photosphere, the Sun's surface, Space.com reported. This apparent contradiction to the general principle that temperature decreases with distance from a heat source has long puzzled astrophysicists and has been dubbed the "coronal heating problem."

Role of High-Frequency Magnetic Waves

In a significant stride towards understanding this enigma, Professor Tom Van Doorsselaere from KU Leuven stated, "For the past 80 years, astrophysicists have grappled with this problem, and now, mounting evidence suggests that the corona may be heated by magnetic waves."

The pivotal discovery stemmed from observations made by the Extreme Ultraviolet Imager (EUI) telescope, stationed on the European Space Agency's Solar Orbiter spacecraft. This telescope, operated by ROB, captures solar corona images with unprecedented clarity, unveiling rapid oscillations within the smallest magnetic structures of the corona. These high-frequency waves contribute to the heating of the Sun's atmosphere.

Unprecedented Insights and Future Prospects

To ascertain the significance of these new, swift oscillations compared to the known slower ones, the researchers conducted a comprehensive meta-analysis. Dr. Daye Lim, the study's lead author, concluded that high-frequency waves play a more substantial role in heating the solar atmosphere than their low-frequency counterparts.

Dr. David Berghmans, the principal investigator of EUI, remarked, "Since her results have indicated the crucial role of fast oscillations in coronal heating, we will dedicate much of our focus to uncovering higher-frequency magnetic waves using EUI."

The findings, which have been published in the Astrophysical Journal Letters, pave the way for a new era of exploration, offering insights into the intricate dynamics of our Sun and its far-reaching impact on our solar system.

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First Published Date: 27 Jul, 08:42 IST