Scientists have unveiled the closest images ever taken of the sun, captured by NASA’s Parker Solar Probe, which flew an astonishing 3.8 million miles above the solar surface. These groundbreaking visuals provide an unparalleled look at how superheated, ionized particles from the sun traverse through space. This crucial information is expected to enhance forecasts of solar storms approaching Earth, which can significantly impact our planet's technology and atmosphere.
Released last week, the striking images were captured in December and depict three solar eruptions merging after occurring in rapid succession. These eruptions, referred to as coronal mass ejections (CMEs), are vast clouds of solar particles and plasma embedded with magnetic fields, visible as brighter bursts in the photos. Among the images, one large CME leads the group, closely followed by two smaller ejections that are catching up.
“These successive events coming from the sun are the most significant threat to Earth regarding space weather,” stated project scientist Nour Rawafi from the Johns Hopkins Applied Physics Laboratory, which designed and operates the spacecraft. Space weather encompasses solar activities such as eruptions or flares that can affect Earth, sometimes resulting in beautiful auroras or technological disruptions.
When solar ejections merge, they can trigger powerful geomagnetic storms on Earth. The initial ejection clears a path for subsequent particles, allowing them to accelerate and lose less energy, as explained by Rawafi. An example of this occurred in May 2024, when a multi-eruption event caused widespread auroras and disrupted communications for numerous commercial satellites. Previous missions only provided hints of such ejections combining, but Rawafi emphasized that the Parker Solar Probe offers a "front seat" view of this fascinating phenomenon.
As these ejections collide, a lingering question remains: Do they merge magnetically or behave like fluids? The images captured by the probe also reveal another intriguing aspect of solar activity: the solar wind. This constant stream of charged particles emitted from the sun combines with ejections to create strong geomagnetic storms that illuminate our skies.
The images clearly depict the solar wind shortly after its release from the sun’s outermost layer, known as the corona. One component of the solar wind, the heliospheric current sheet, extends from the sun like a swirling skirt. This invisible boundary defines where the sun’s magnetic field direction switches from north to south and is ever-present, albeit shifting in shape and location. In the captured images, the heliospheric current sheet appears more vividly than other aspects of the solar wind, resembling a bright ray from approximately 90 million miles away.
As the Parker Solar Probe approached and even crossed the current sheet, it revealed the structures underlying this sheet. The stream of charged particles can slow down a solar eruption directed toward Earth, but a large solar eruption can disrupt it, making multi-eruption events particularly potent. “Understanding the background solar wind will aid us in predicting when these events will reach Earth, their intensity, and the likely atmospheric activity they will induce,” Rawafi noted.
The remarkable images were collected during the Parker Solar Probe's closest approach to the sun on December 24, flying at a record speed of 430,000 mph through the solar atmosphere. Just two days after this historic journey, the probe sent a signal back to Earth confirming not only its survival but also its normal operation. The onboard camera, known as the Wide-Field Imager for Solar Probe (WISPR), collected numerous snapshots, with more images yet to be released.
Since its launch in 2018, the Parker Solar Probe has been on a mission to study the sun, capturing images along its path. When it crossed into the sun’s corona about 8 million miles away in 2021, it revealed the corona boundary's complexity. However, no previous images come close to the detail captured by this recent close-up.
As the Parker Solar Probe continues its orbit, it will make additional passes at a distance of 3.8 million miles, gathering more high-quality data. Rawafi described the excitement among scientists as they previewed some of the new images, expressing astonishment at the findings. “It’s really the complex dynamics that capture the imagination of people,” he remarked. “We invested so much time and effort, generation after generation, into this project. But witnessing the incredible data we are receiving makes it all worthwhile.”
