The European Space Agency’s (ESA) Solar Orbiter spacecraft has provided the most detailed images of the Sun’s surface ever. The images, taken in March 2023 from a distance of about 74 million kilometers, were released on November 20. These photos provide unprecedented insight into the atmosphere, which is responsible for emitting sunlight. The images show complex and dynamic patterns of granules — plasma cells about 1,000 km wide — formed by convection as hot plasma rises and cold plasma sinks.

Sunspot activity and magnetic fields were analyzed.

The images show sunspots as cold, dark regions on the photosphere, where strong magnetic fields disrupt the movement of plasma. The Polarimetric and Helioseismic Imager (PHI) aboard the Solar Orbiter produced detailed maps of these magnetic fields, indicating their main concentrations in sunspot regions. According to Daniel Müller, ESA Project Scientist for Solar Orbiters, said these observations are essential to understanding the dynamics of the Sun. Sunspots appear colder because magnetic forces restrict normal motion, causing the surface temperature to drop.

New data on solar rotation and winds

A velocity map, called a tachogram, is also shared, showing the speed and direction of material movement on the surface of the Sun. Blue regions show plasma moving toward the spacecraft, while red regions show plasma moving away, reflecting the rotational dynamics of the Sun. Additionally, magnetic fields in sunspot regions were observed to further affect the surface material.

The Sun’s outer atmosphere, the corona, was imaged by the spacecraft’s Extreme Ultraviolet Imager. Plasma loops from the Sun, visible in these images, are connected to sunspots and contribute to the solar wind. This solar wind, when it reaches Earth, often results in an auroral display.

Future missions to study the solar poles

The Solar Orbiter, launched in 2020 as a joint mission with NASA, aims to capture unprecedented views of the Sun’s poles. The observations are scheduled for 2025, when the spacecraft’s orbit will be aligned for a direct approach. Recent imaging involved the assembly of 25 small images, a complex process that is now expected to accelerate for future releases.