The Sun completes a full rotation approximately every 28 days, a cycle that significantly dictates how solar activity is monitored from our planet. Due to this relatively slow rotational period, observers on Earth are restricted to viewing any specific active region on the solar surface for a duration of roughly two weeks. Once a region rotates beyond the terrestrial line of sight, it remains obscured for another two weeks before eventually reappearing.
The impact of the solar orbiter mission
The limitations of Earth-based observation have been effectively mitigated by the Solar Orbiter mission, which was launched by the European Space Agency (ESA) in 2020. According to Ioannis Kontogiannis, a solar physicist at ETH Zurich and the Aldo and Cele Daccò Solar Research Institute (IRSOL) in Locarno, this mission has significantly broadened our observational perspectives. Unlike stationary or Earth-orbiting observers, the Solar Orbiter follows an expansive trajectory that circles the Sun every six months, allowing the probe to document areas of the Sun—including its far side—that are typically hidden from Earth's view.
Between April and July 2024, the Solar Orbiter captured comprehensive data on one of the most intense solar regions recorded in the last twenty years. This region, designated as NOAA 13664, became visible from Earth in May 2024 and immediately demonstrated its volatility by triggering the most powerful geomagnetic storms since 2003. Louise Harra, a professor at ETH Zurich and Director of the Physical Meteorological Observatory Davos, notes that this specific region was responsible for the extraordinary aurora borealis displays that were visible as far south as Switzerland.
To gain a deeper understanding of the formation and evolution of such extreme solar environments, Professor Harra and Dr. Kontogiannis convened an international research team. By integrating observations from two distinct spacecraft, the scientists have succeeded in constructing a far more exhaustive and nuanced profile of NOAA 13664 than was previously possible through single-perspective monitoring.
Data integration and continuous monitoring
The Solar Orbiter provided critical data from the far side of the Sun, while NASA’s Solar Dynamics Observatory maintained continuous observations from the Earth-Sun line, monitoring the solar hemisphere facing our planet. By synthesizing these distinct datasets, researchers successfully tracked the active region NOAA 13664 with almost no interruption for a period of 94 days. This comprehensive monitoring began with the region's initial emergence on the far side of the Sun on April 16, 2024, and continued through its full evolution and ultimate decay after July 18, 2024. This extended timeline offered scientists a rare opportunity to document subtle transitions and developments that would typically remain undetected.
Active solar regions are characterized by powerful and intricate magnetic fields. These zones manifest when highly magnetized plasma rises from the solar interior and penetrates the surface. As these magnetic fields become increasingly entangled and unstable, they can release vast amounts of energy in spectacular displays. Such events result in solar flares, which are intense bursts of electromagnetic radiation, and coronal mass ejections that propel immense quantities of plasma and high-energy particles across the solar system.
While solar storms are celebrated for generating the aurora borealis, their impact extends significantly into the realm of modern infrastructure. Extreme space weather conditions possess the potential to destabilize power grids, interfere with global communication systems, and heighten radiation exposure for flight crews. Satellites are particularly susceptible to these forces, as evidenced in February 2022 when SpaceX lost 38 of its 49 Starlink satellites just two days after launch due to heightened solar activity. Professor Harra further highlights the risks to terrestrial safety, noting that railway signaling systems can be erroneously triggered, a phenomenon that poses significant operational dangers.
The activity associated with NOAA 13664 in May 2024 caused substantial disruptions to modern digital agriculture. Dr. Kontogiannis explains that interference with signals from satellites, drones, and specialized sensors led to significant operational downtime for farmers and subsequent crop losses, resulting in notable economic damage. These events serve as a poignant reminder that the Sun is the only star directly influencing human activity. Given our proximity to this celestial body, the scientific community emphasizes the vital importance of observing and understanding solar mechanics to better safeguard our technological environment.
Longitudinal observation of solar evolution
For the first time, researchers successfully tracked a single, highly active solar region across three complete rotations of the Sun. This unprecedented continuity allowed the scientific team to document the step-by-step evolution of its magnetic structure, which grew increasingly sophisticated over several months. This progressive accumulation of magnetic energy culminated in a tightly interconnected configuration, eventually triggering the most powerful solar flare recorded in the last two decades on May 20, 2024, while the region was positioned on the far side of the Sun.
The primary objective behind these detailed observations is the development of more precise models for predicting solar storms and their subsequent impact on Earth. Enhanced space weather forecasting is essential for the protection of satellite constellations, global energy infrastructure, and other sensitive modern technologies. Professor Harra explains that identifying regions with exceptionally complex magnetic fields allows scientists to infer the presence of significant energy reserves, which must inevitably be discharged through solar eruptions.
Despite these advancements, the ability to forecast the exact timing and magnitude of specific eruptions remains a significant challenge for the scientific community. Currently, researchers cannot definitively determine whether an active region will produce a singular massive event or a series of smaller disruptions, nor can they pinpoint the precise moment of such occurrences. To address these limitations, the European Space Agency is developing a new dedicated spacecraft known as Vigil. Scheduled for launch in 2031, this mission will be specifically tasked with refining our understanding of space weather and improving our early warning capabilities.
The study was published in Astronomy & Astrophysics.
Post a Comment