(CNN) – New images of the Sun from the Solar Orbiter mission show the highest resolution images of the visible surface of our star taken to date, showing sunspots and a constantly moving charged gas called plasma. The images could give heliophysicists new clues that could help unlock the mysteries of the Sun like never before.
The images, taken on March 22, 2023, and released Wednesday, show various dynamic aspects of the Sun, including movements of its magnetic field and the glow of the super-hot solar corona, or outer atmosphere.
The spacecraft used two of its six imaging instruments, the Extreme Ultraviolet Imager (EUI) and the Polarimetric and Helioseismic Imager (PHI), to capture images at a distance of 74 million kilometers.
Solar Orbiter, a joint mission of the European Space Agency and NASA launched in February 2020, orbits the Sun at an average distance of 42 million kilometers. Missions like Solar Orbiter and NASA’s Parker Solar Probe are helping answer key questions about the golden ball, such as what powers its stream of charged particles, called the solar wind, and why the corona is so much hotter than the sun’s surface.
The Parker Solar probe will come the closest the spacecraft will attempt to the Sun in late December, and Solar Orbiter will be responsible for taking the closest images of the solar surface in history. Parker Solar’s flight path will be too close to the Sun to carry cameras and telescopes, but Solar Orbiter is equipped with a variety of instruments to share its unique observations of the Sun.
Additionally, Solar Orbiter and the Parker Solar probe are studying the Sun up close at the perfect time: during the peak of its annual cycle.
“The Sun’s magnetic field is key to understanding the dynamical nature of our star, from the smallest to the largest scales,” Solar Orbiter project scientist Daniel Müller said in a statement.
“These new high-resolution maps from the PHI Solar Orbiter instrument show in great detail the beauty of the Sun’s surface magnetic field and its fluxes. At the same time, they are crucial for determining the magnetic field in the hot corona of the Sun, which is imaged by our EUI instrument.”
Together, the new images reveal the varied and complex layers of the Sun.
The Polarimetric and Helioseismic Imager (PHI) has produced the highest resolution complete images of the Sun’s visible surface, or photosphere, to date. Almost all solar radiation comes from the photosphere, whose temperature ranges from 4,500 to 6,000 °C (8,132 to 10,832 °F).
Under the photosphere layer there is hot plasma moving in the convection zone of the Sun, just as hot magma moves in the Earth’s mantle.
The purpose of the PHI instrument is to map the brightness of the photosphere and measure the speed and direction of the Sun’s magnetic fields.
A visible light image of the photosphere shows sunspots that resemble holes on the surface of the Sun. These dark regions, some of which can be as large as the Earth or larger, are governed by the Sun’s strong, ever-changing magnetic fields. Sunspots, areas where the Sun’s magnetic field passes through the surface, are cooler than the surrounding environment and emit less light.
The PHI instrument also allowed scientists to obtain a magnetic map, or magnetogram, showing the concentration of the Sun’s magnetic field in its sunspot regions. Normally, convection helps transfer heat from the Sun’s interior to its surface, but this process is disrupted when charged particles are forced to follow magnetic field lines that cluster around sunspots.
Scientists also measured the speed and direction of material on the sun’s surface using a velocity map, or “shorthand.” The blue parts indicate movement towards the solar orbiter, and the red parts indicate movement away from the spacecraft.
Typically, the charged gas on the surface of the Sun moves parallel to the Sun’s rotation around its axis, and the plasma moves around sunspots.
For its part, the Extreme Ultraviolet Imager (EUI) is observing the solar corona to help determine why it is so much hotter than the photosphere, reaching 1.8 million °F (1 million °C). The EUI image of the corona gives a glimpse of what’s happening above the photosphere, and hot, bright plasma can be seen protruding from sunspot regions.
Given Solar Orbiter’s proximity to the Sun, the spacecraft had to be rotated after each image to capture every part of the Sun’s face. As a result, each image is a mosaic of 25 individual images.
Mark Misch, a scientist at the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center, acknowledged that the images show both large-scale features such as solar magnetism and small-scale surface features. Misch was not involved in the publication of the images.
“The closer we look, the more we see,” said Misch, who is also a researcher at the University of Colorado Cooperative Research Institute for Environmental Sciences. “To understand the complex interplay between the big and the small, between curved magnetic fields and swirling currents, we need to see the Sun in all its splendor. These high-resolution images from Solar Orbiter bring us closer than ever to this goal.”
Scientists from NOAA, NASA and the International Solar Cycle Prediction Group announced in October that the Sun has reached solar maximum, or peak activity, during its 11-year cycle. At the peak of the solar cycle, the Sun’s magnetic poles change position, causing the Sun to move from quiet to active. Experts record the increase in solar activity by counting the number of sunspots appearing on its surface. The Sun is expected to remain active throughout the next year.
“This announcement does not mean that this is the peak solar activity that we will see in this solar cycle,” Elsayed Talaat, director of space weather observations at NOAA, said at a news conference in October. “Although the Sun has reached its solar maximum period, the month in which solar activity peaks will not be determined for months or years.”
Solar activity, including flares or coronal mass ejections, creates space weather that impacts Earth. Coronal mass ejections are large clouds of ionized gas called plasma and magnetic fields that erupt from the sun’s outer atmosphere. Solar storms can affect power grids, GPS and aviation, as well as satellites in low Earth orbit. Storm activity also causes radio communications blackouts and even poses a risk to human spaceflight.
Storms are also responsible for creating the auroras that dance around the Earth’s poles, known as the northern and southern lights. When charged coronal mass ejection particles reach Earth’s magnetic field, they interact with gases in the atmosphere, creating colorful lights in the sky.
On December 24, the Parker Solar probe will approach the surface of the Sun at a distance of 6.2 million kilometers, which will be the closest to the Sun of any artificial object. The flyby could help scientists study the origins of space weather right at the source, as the probe will get close enough to pass through the plasma plumes and solar flares associated with the Sun.