The images show three solar eruptions combining, which can lead to powerful geomagnetic storms on Earth. Photo / Nasa
Scientists have released the closest images ever taken near the sun, captured by Nasa’s Parker Solar Probe flying 6 million km above the solar surface.
In unprecedented detail, the visuals reveal how superhot ionised particles from the sun travel through space, providing information that can help improve forecasts of solar storms headed towards Earth.
The striking images, snapped in December and released last week, show three solar eruptions combining after occurring in close succession.
These eruptions, known as coronal mass ejections, are large clouds of solar particles and plasma with embedded magnetic fields – picked up as brighter bursts in the images.
One large cloud leads the pack, followed shortly by two smaller ejections catching up to it.
“These successive events coming from the sun actually are the biggest threat to Earth in terms of space weather,” said project scientist Nour Rawafi of the Johns Hopkins Applied Physics Laboratory, which built and operates the spacecraft.
Space weather refers to solar activity, like eruptions or flares, that can affect Earth – sometimes causing the aurora or disrupting the planet’s technology.
When such ejections combine, it can lead to a powerful geomagnetic storm on Earth. The initial ejection clears the pathway of particles, allowing the following eruptions to move faster and lose less energy, Rawafi said.
In May 2024, a multi-eruption event brought widespread auroras and knocked out communications for some commercial satellites.
Scientists previously saw only hints of such ejections combining, but Rawafi said the Parker Solar Probe is “basically giving you a front seat to see that happening”.
But, as they collide, he said, there’s a lingering question: do they combine magnetically or merge like fluids?
More data from the spacecraft may help solve this and similar questions.
In the background of these eruptions, the photos show another intriguing aspect of the sun: the solar wind, which is a constant stream of charged particles emitted from the sun.
Together with ejections from the sun, they also can deliver strong geomagnetic storms to Earth that brighten our skies.
Specifically, the images show the solar wind shortly after it is released from the sun’s outermost layer, called the corona.
One part of the solar wind is the heliospheric current sheet, which protrudes from the sun like a twirling skirt.
It’s an invisible boundary that delineates where the sun’s magnetic field direction switches from north to south. It’s always around, although it can sometimes change shape and location.
In the images, the heliospheric current sheet can be seen more clearly and brightly than other parts of the solar wind. From about 145 million km away, other images showed the current sheet as just a bright ray.
But as the Parker Solar Probe got closer and even crossed the sheet, it showed the structures that formed the sheet.
The stream of charged particles can slow down a solar eruption headed towards Earth. But it can be disrupted by a large solar eruption, which is why multi-eruption events can be particularly powerful.
“Understanding the background solar wind will help us to predict when these events are going to arrive to Earth, how strong are they going to be and what is the likely activity that will drive in the Earth’s atmosphere,” Rawafi said.
The images were collected when the Parker Solar Probe made its closest approach to the sun on December 24.
At 6 million km away, it flew through the solar atmosphere at 692,000km/h – a record speed for any human-made object.
After about two days, it sent a signal back to Earth and indicated that it not only survived the historic journey but was also operating normally.
The onboard camera, called the Wide-Field Imager for Solar Probe, or WISPR, collected numerous snapshots still to be released.
The Parker Solar Probe has been on its journey to the sun since 2018, snapping pictures along the way. When it crossed into the sun’s corona at about 13 million km away in 2021, it noticed that the corona boundary was intriguingly more complex. But no previous images rival the detail of the pictures taken so close to the sun.
In its orbit, the spacecraft will make more passes from 6 million km as it’s able to, collecting more high-quality data.
Rawafi described sharing a sneak peek of some of the images. Scientists, he said, were astonished by what they saw.
“It’s really the complex dynamics that capture the imagination of people,” he said.
“We invested so much time and so much effort, generation after generation, to it. But when you see what we are getting back from it, it’s all worthwhile.”