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NASA’s Parker Solar Probe Snaps Closest-Ever Images to Sun
KEY POINTS
- NASA’s Parker Solar Probe has taken the closest ever images to the Sun, captured just 3.8 million miles from the solar surface.
- The new close-up images show features in the solar wind, the constant stream of electrically charged subatomic particles released by the Sun that rage across the solar system at speeds exceeding 1 million miles an hour.
- These images, and other data, are helping scientists understand the mysteries of the solar wind, which is essential to understanding its effects at Earth.
On its record-breaking pass by the Sun late last year, NASA’s Parker Solar Probe captured stunning new images from within the Sun’s atmosphere. These newly released images — taken closer to the Sun than we’ve ever been before — are helping scientists better understand the Sun’s influence across the solar system, including events that can affect Earth.
“Parker Solar Probe has once again transported us into the dynamic atmosphere of our closest star,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington. “We are witnessing where space weather threats to Earth begin, with our eyes, not just with models. This new data will help us vastly improve our space weather predictions to ensure the safety of our astronauts and the protection of our technology here on Earth and throughout the solar system.”
Parker Solar Probe started its closest approach to the Sun on Dec. 24, 2024, flying just 3.8 million miles from the solar surface. As it skimmed through the Sun’s outer atmosphere, called the corona, in the days around the perihelion, it collected data with an array of scientific instruments, including the Wide-Field Imager for Solar Probe, or WISPR.
Credit: NASA’s Goddard Space Flight Center/Joy Ng
The new WISPR images reveal the corona and solar wind, a constant stream of electrically charged particles from the Sun that rage across the solar system. The solar wind expands throughout of the solar system with wide-ranging effects. Together with outbursts of material and magnetic currents from the Sun, it helps generate auroras, strip planetary atmospheres, and induce electric currents that can overwhelm power grids and affect communications at Earth. Understanding the impact of solar wind starts with understanding its origins at the Sun.
The WISPR images give scientists a closer look at what happens to the solar wind shortly after it is released from the corona. The images show the important boundary where the Sun’s magnetic field direction switches from northward to southward, called the heliospheric current sheet. It also captures the collision of multiple coronal mass ejections, or CMEs — large outbursts of charged particles that are a key driver of space weather — for the first time in high resolution.
“In these images, we’re seeing the CMEs basically piling up on top of one another,” said Angelos Vourlidas, the WISPR instrument scientist at the Johns Hopkins Applied Physics Laboratory, which designed, built, and operates the spacecraft in Laurel, Maryland. “We’re using this to figure out how the CMEs merge together, which can be important for space weather.”
When CMEs collide, their trajectory can change, making it harder to predict where they’ll end up. Their merger can also accelerate charged particles and mix magnetic fields, which makes the CMEs’ effects potentially more dangerous to astronauts and satellites in space and technology on the ground. Parker Solar Probe’s close-up view helps scientists better prepare for such space weather effects at Earth and beyond.
Zooming in on Solar Wind’s Origins
The solar wind was first theorized by preeminent heliophysicist Eugene Parker in 1958. His theories about the solar wind, which were met with criticism at the time, revolutionized how we see our solar system. Prior to Parker Solar Probe’s launch in 2018, NASA and its international partners led missions like Mariner 2, Helios, Ulysses, Wind, and ACE that helped scientists understand the origins of the solar wind — but from a distance. Parker Solar Probe, named in honor of the late scientist, is filling in the gaps of our understanding much closer to the Sun.
At Earth, the solar wind is mostly a consistent breeze, but Parker Solar Probe found it’s anything but at the Sun. When the spacecraft reached within 14.7 million miles from the Sun, it encountered zig-zagging magnetic fields — a feature known as switchbacks. Using Parker Solar Probe’s data, scientists discovered that these switchbacks, which came in clumps, were more common than expected.
When Parker Solar Probe first crossed into the corona about 8 million miles from the Sun’s surface in 2021, it noticed the boundary of the corona was uneven and more complex than previously thought.
As it got even closer, Parker Solar Probe helped scientists pinpoint the origin of switchbacks at patches on the visible surface of the Sun where magnetic funnels form. In 2024 scientists announced that the fast solar wind — one of two main classes of the solar wind — is in part powered by these switchbacks, adding to a 50-year-old mystery.
However, it would take a closer view to understand the slow solar wind, which travels at just 220 miles per second, half the speed of the fast solar wind.
“The big unknown has been: how is the solar wind generated, and how does it manage to escape the Sun’s immense gravitational pull?” said Nour Rawafi, the project scientist for Parker Solar Probe at the Johns Hopkins Applied Physics Laboratory. “Understanding this continuous flow of particles, particularly the slow solar wind, is a major challenge, especially given the diversity in the properties of these streams — but with Parker Solar Probe, we’re closer than ever to uncovering their origins and how they evolve.”
Understanding Slow Solar Wind
The slow solar wind, which is twice as dense and more variable than fast solar wind, is important to study because its interplay with the fast solar wind can create moderately strong solar storm conditions at Earth sometimes rivaling those from CMEs.
Prior to Parker Solar Probe, distant observations suggested there are actually two varieties of slow solar wind, distinguished by the orientation or variability of their magnetic fields. One type of slow solar wind, called Alfvénic, has small-scale switchbacks. The second type, called non-Alfvénic, doesn’t show these variations in its magnetic field.
As it spiraled closer to the Sun, Parker Solar Probe confirmed there are indeed two types. Its close-up views are also helping scientists differentiate the origins of the two types, which scientists believe are unique. The non-Alfvénic wind may come off features called helmet streamers — large loops connecting active regions where some particles can heat up enough to escape — whereas Alfvénic wind might originate near coronal holes, or dark, cool regions in the corona.
In its current orbit, bringing the spacecraft just 3.8 million miles from the Sun, Parker Solar Probe will continue to gather additional data during its upcoming passes through the corona to help scientists confirm the slow solar wind’s origins. The next pass comes Sept. 15, 2025.
“We don’t have a final consensus yet, but we have a whole lot of new intriguing data,” said Adam Szabo, Parker Solar Probe mission scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
By Mara Johnson-Groh
NASA’s Goddard Space Flight Center, Greenbelt, Md.
