Wednesday 09 April 2025
Scientists have long been fascinated by the mysterious threads of plasma that burst forth from the surface of the sun, known as spicules. These towering columns of hot gas can reach heights of over 10,000 kilometers and are thought to play a crucial role in heating the sun’s corona, the outer atmosphere of our star.
But despite their importance, spicules have proven difficult to study. They’re tiny, fleeting, and occur at incredibly high temperatures, making it challenging for scientists to get a good look at them. Until now, that is. A new paper published in The Astrophysical Journal Letters has revealed the most detailed observations of spicules yet, using a combination of cutting-edge telescopes and sophisticated data analysis techniques.
The study focused on two quiet regions of the sun’s surface, where spicules are more common than in areas with intense magnetic activity. Using the Interface Region Imaging Spectrograph (IRIS) and the Atmospheric Imaging Assembly (AIA) instruments on board the Solar Dynamics Observatory (SDO), researchers were able to capture high-resolution images and spectra of the spicules.
The results were astonishing. The team discovered that spicules are much more common than previously thought, with thousands of them erupting from the sun’s surface every minute. They also found that these columns of plasma are incredibly dynamic, with temperatures ranging from a scorching 10 million degrees Celsius to a relatively cool 1 million degrees.
But perhaps most excitingly, the researchers were able to observe the spicules as they transitioned from the chromosphere, the sun’s lower atmosphere, into the corona. This is a critical moment in the heating process, and scientists have long been trying to understand how it occurs.
The new observations suggest that the spicules are heated by magnetic reconnection, a process where magnetic field lines are torn apart and then reform, releasing a massive amount of energy in the process. This energy is thought to be responsible for heating the corona to its incredibly high temperatures.
The implications of this study are significant. By better understanding how spicules heat the corona, scientists may be able to improve their models of solar activity and even predict when the sun will erupt in a powerful flare or coronal mass ejection (CME). These events can have devastating effects on Earth’s magnetic field and technology, so being able to anticipate them would be a major breakthrough.
Cite this article: “Unveiling the Million-Degree Secret of Solar Spicules”, The Science Archive, 2025.
Sun, Spicules, Plasma, Corona, Solar Activity, Magnetic Reconnection, Chromosphere, Atmospheric Imaging Assembly, Interface Region Imaging Spectrograph, Solar Dynamics Observatory
