NAT GEO * Explosive new images of the sun*

A sequence of ultraviolet images from the Solar Orbiter spacecraft as it was nearing a close approach to the sun in 2022. The images captured the gases in the sun’s atmosphere, which reach a temperature of around one million degrees.




Explosive new images of the sun may help unravel long-standing mysteries
Views from a new telescope in Hawaii and clues from spacecraft orbiting the sun could not only help us understand how stars work—they could help us predict solar activity that threatens Earth.


The sun is the heart of our planetary system, and while it may appear the same to us each day in the sky, that doesn’t mean it isn’t changing. Our star is a dynamic sphere of pulsating heated plasma, and currently it is approaching solar maximum—a peak of activity that occurs about every 11 years.
Thanks to the new Daniel K. Inouye Solar Telescope in Hawaii, which produces the highest resolution images of the sun's surface ever taken, scientists are getting an unprecedented look at our star’s roiling structures. Additionally, two spacecraft are orbiting closer to the sun than ever before. The details glimpsed by scientists can help us understand how stars work, and they give us the tools to understand and perhaps even predict explosive flares and other solar activity that could threaten Earth.





Resembling the flowers that bear its name, the sun blisters and bubbles in this image of its surface taken by the Daniel K. Inouye Solar Telescope in Hawaii. The dark sunspots are transient areas of cooler material, produced by intense magnetic fields that can also trigger solar flares and ejections. Convecti...
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PHOTOGRAPH BY NSO/AURA/NSF

“From the data we already got, we’ve opened so many new questions, and we’ve discovered phenomena that we didn’t even know existed,” says astrophysicist Nour Raouafi of Johns Hopkins University in Laurel, Maryland, the project scientist of NASA’s Parker Solar Probe, one of the spacecraft currently orbiting the sun.
The Inouye Solar Telescope, which began science operations in 2022, can image features on the sun as small as 20 kilometers. Images from the telescope show convective cells that scientists call granules, where hot plasma is rising from below and cooler material is sinking down—one of the motions generating a complex web of magnetic fields.
These magnetic fields periodically cause Jupiter-size flares and even larger blasts called coronal mass ejections (CMEs). The larger blasts send charged particles to nearly the speed of light, and if those particles hit Earth, they can affect our planet’s magnetic field and create stunning aurora light shows. But those same particles can also knock out satellites, shut down power grids, and even harm astronauts in space.
















During the Parker Solar Probe’s eighth orbit around the sun, the spacecraft flew through structures in the corona called streamers. This video was taken by the Wide-Field Imager (WISPR) instrument.

Parker and another spacecraft, the European Solar Orbiter, are beginning to untangle the threads of the sun’s magnetism, and they’re learning how small flares and explosions are crucial to driving solar activity. Scientists have found from models that some of these magnetic fields twist, spanning just tens of feet, and snap in seconds—tiny events that can hurl huge amounts of plasma into space.
With new views of the sun, scientists can not only plan to protect our astronauts and electronics from any harmful solar eruptions, they could also learn about the mysterious physical processes that power stars across the universe.

Into our star

The sun is the only star scientists can investigate in detail, and the only one they can watch evolve in real time. Like other stars, the sun is a giant ball of hot plasma; it’s so hot that the gas atoms can’t hold on to their electrons. Layers of negatively charged electrons and positively charged particles called ions flow, like liquid, through the sun’s interior. Those flows of charged plasma generate the threads of the sun’s magnetic fields.












One of the highest resolution images ever taken of the sun’s south pole, as seen by the Solar Orbiter spacecraft’s Extreme Ultraviolet Imager just four days after the spacecraft passed its closest point to the sun in 2022.
IMAGE BY ESA & NASA/SOLAR ORBITER/EUI TEAM


Roiling plasma moves through the sun, rotating at different speeds as the sun spins. Material closer to the surface also rises and falls, like liquid boiling in a pan. At the surface, we see this convection occurring in structures that scientists call granules, creating a scale-like pattern on the surface, as seen in images from the Inouye Solar Telescope.
Magnetic field lines pierce the surface as loops, twisting and dancing. Sometimes those cross one another, twist further, and like a rubber band, they snap with a burst of hot and fast-moving plasma and radiation. “You now have a sudden release of plasma that's driven by what’s called magnetic reconnection,” says solar astrophysicist Yeimy Rivera of the Harvard Smithsonian Center for Astrophysics. “That happens in a very explosive way.” The bursts can be tiny in solar scales (a bit bigger than the island of Sicily), while others are enormous mass ejections, larger than a planet.










A mosaic of images from the sun's south pole shows a multitude of tiny jets of material, taken by the Solar Orbiter spacecraft. These events could be the long-sought-after mechanism behind the solar wind, the constant outflow of charged particles that comes from the sun and flows through the solar sy...
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MOSAIC BY ESA & NASA/SOLAR ORBITER/EUI TEAM

Above that churning surface is the sun’s atmosphere, or corona, where diffuse hot gas floats. Mysteriously, this part of the sun is hotter than the material at the surface, which is around 10,000 degrees Fahrenheit. One would expect that as you move away from a hot object, things would get cooler. “But that does not work with the corona,” says Raouafi. Instead, the corona is millions of degrees—and scientists don’t know how or why.


The corona flows into the solar wind, which speeds away from the sun at about a million miles an hour, out to the edges of the solar system. But what’s driving this high speed is only starting to be understood.

Getting a closer look

Observations with the Solar Orbiter, which has been orbiting the sun since 2020, have found many tiny jets bursting forth on the surface, the result of small-scale magnetic fields catching, twisting, and breaking. Those jets of hot plasma are channeled into the corona, carrying mass and energy into the solar wind, says solar physicist Lakshmi Pradeep Chitta of the Max Planck Institute for Solar System Research in Göttingen, Germany, who led a recent study about these jets.





The chromosphere, part of the sun’s atmosphere just above the surface, taken with the Daniel K. Inouye Solar Telescope. The image shows a region 51,263 miles across with the Earth overlaid for scale.
COMPOSITE BY NSO/AURA/NSF

The Parker Solar Probe, orbiting the sun since 2018, has also spied small flares launching by snapping magnetic fields. The team calls these jetlets, and they contribute to energizing the solar wind.
“That is totally different from the picture that we knew for decades,” says Raouafi, who led a recent study about this discovery. The solar wind doesn’t just gently blow away from the corona, but instead it is formed by many small explosions.
Parker has also witnessed the sun’s enormous coronal mass ejections, which spew extremely high-speed particles. The spacecraft flew headlong into one of these CMEs last fall. “You can see the violence of that event,” says Raouafi. The blast “basically acted like a vacuum cleaner,” clearing away any particles and even heavier molecules of dust.
“As we are collecting more and more of these events, we will actually learn how the energetic particles get almost to the speed of light,” says Raouafi. “And that will be a huge breakthrough for us.”

A magnetic machine

 Behind the sun’s many bursts and blasts are the constantly changing forces of magnetism. “The force that will propel everything that can impact the Earth … is powered by the sun's magnetic field,” says University of Montreal physicist Paul Charbonneau.








NASA's Solar Dynamics Observatory watches the sun constantly, and it captured this solar flare, one of the most intense ever seen, on January 9, 2023. Flares and solar eruptions can impact radio communications, electric power grids, navigation signals, and pose risks to spacecraft and astronauts.
IMAGE BY NASA/GSFC/SDO

Flowing electric currents within the sun are so complex that supercomputer models can’t simulate what is happening well enough to match real-world observations. But what researchers do know from centuries of documented observations is that the sun follows a roughly 11-year cycle, where our star’s magnetic activity reaches a minimum, increases to a maximum, and then drops again.
The most recent minimum was in 2019, and the next maximum is expected to peak in 2024 or 2025. As the sun spins, the magnetic fields wrap tighter around the sphere and start to move. Researchers think the fields gather at the sun’s poles, and somehow, “at the end of the solar cycle, the magnetic field that is piled up near the poles of the sun gets dragged inside,” says Charbonneau. Yet scientists don’t know how that happens, or even if it happens, because no telescope that can detect magnetic fields has seen the solar poles. But that’s about to change.
Solar Orbiter is slowing tilting its orbit so that in four to five years, says Chitta, the spacecraft should have a view of the north and south poles. “We can actually track the magnetic fields and then the flow structure at the poles, which will be adding one important missing link,” says Chitta.
As the sun revs up to solar maximum, scientists will be watching, and what they see could transform what we know about the star that our home planet depends on.