Recent developments in solar research have brought forth groundbreaking images captured by the Solar Orbiter mission, revealing the highest-resolution views of the sun’s visible surface ever obtained. These spectacular photographs display the intricacies of sunspots as well as the dynamic movement of charged gas, known as plasma, providing heliophysicists with unprecedented insights into our star. The significance of these images extends far beyond their beauty, as they are instrumental in uncovering the sun’s many mysteries.
The latest images were taken on March 22, 2023, and were made public shortly thereafter. They reveal several aspects of solar dynamics, including the shifting magnetic fields and the radiant glow of the sun’s ultrahot corona, or outer atmosphere. The Solar Orbiter utilizes two out of its six imaging instruments: the Extreme Ultraviolet Imager (EUI) and the Polarimetric and Helioseismic Imager (PHI). These instruments captured intricate details from a staggering distance of approximately 46 million miles (74 million kilometers) away.
The Solar Orbiter, an ambitious collaborative mission between the European Space Agency (ESA) and NASA, was launched in February 2020 and orbits the sun at an average distance of about 26 million miles (42 million kilometers). This spacecraft, alongside NASA’s Parker Solar Probe, is crucial in addressing essential questions about the sun, such as the mechanics behind the solar wind—a stream of charged particles emitted from the sun—and why the corona is significantly hotter than the photosphere.
Anticipation builds around the Parker Solar Probe, which is set to make the closest approach to the sun by any spacecraft in late December. While it lacks the capability to carry imaging instruments due to its proximity, the Solar Orbiter is equipped with several key tools that allow it to capture exceptionally close images of the sun’s surface. Both missions are strategically timed to study the sun during a period of heightened activity—known as the solar maximum—within the sun’s 11-year cycle.
Daniel Müller, Solar Orbiter’s project scientist, emphasized the importance of understanding the sun’s magnetic field: “The Sun’s magnetic field is key to understanding the dynamic nature of our home star.” The latest high-resolution maps produced by the PHI instrument vividly depict the solar surface’s magnetic field and dynamic flows, providing vital information about the magnetic field within the sun’s hot corona.
The recent findings illustrate the sun’s complex and multi-layered structure. The PHI instrument has captured the highest-resolution images of the sun’s visible surface, or photosphere, to date. The photosphere emits nearly all the radiation we perceive from the sun, with temperatures soaring between 8,132 and 10,832 degrees Fahrenheit (4,500 and 6,000 degrees Celsius). Beneath this layer lies hot plasma in the convection zone, akin to the movement of magma within Earth’s mantle.
The PHI also enables scientists to map the brightness of the photosphere while measuring the movement and direction of the sun’s magnetic fields. The visible light images reveal sunspots—dark areas on the solar surface resulting from the sun’s continuously varying magnetic fields. Some sunspots can be immense, even larger than Earth, exhibiting cooler temperatures and reduced brightness compared to their surroundings.
In addition to magnetic maps of sunspots, scientists have created velocity maps that depict the material’s speed and direction on the sun’s surface. The maps illustrate that charged gas generally follows the sun’s rotation, while plasma is forced away around sunspot areas. Concurrently, the Extreme Ultraviolet Imager analyzes the corona and provides insights into why it exhibits significantly higher temperatures—up to 1.8 million degrees Fahrenheit (1 million degrees Celsius)—than the photosphere.
With Solar Orbiter’s proximity to the sun, each image represents a composite of 25 individual captures, requiring the spacecraft to rotate after taking each picture. This intricate mosaic reveals not only large-scale features like solar magnetism but also small-scale surface details, highlighting the evolution of solar dynamics. Mark Miesch, a research scientist, stated, “The closer we look, the more we see,” emphasizing the importance of these high-resolution images for comprehending the complex interactions between varying features on the sun.
As scientists from NOAA, NASA, and the international Solar Cycle Prediction Panel announce the sun’s attainment of solar maximum, understanding its activities becomes increasingly pertinent. This period of heightened solar activity, marked by the sun’s magnetic poles flipping and intensified sunspot formations, is anticipated to impact various technologies on Earth. Events such as flares and coronal mass ejections generated by the sun can disrupt electric power grids, GPS systems, and aviation, in addition to posing risks to space missions.
The solar storms initiated by coronal mass ejections lead to mesmerizing auroras, commonly known as the northern and southern lights. These stunning displays occur when energized particles collide with Earth’s magnetic field and atmospheric gases, creating vibrant lights in the skies. The Parker Solar Probe’s upcoming flyby on December
