Solar Orbiter: The Spacecraft That Flew Into the Sun's Magnetic Switchbacks — and Finally Traced Where They Come From

The solar wind is blowing past Earth right now. Half a million kilometres per hour. Invisible. Constant. And buried inside it, there are knots in the magnetic field that bend physics in ways scientists have never been able to fully explain.

Until this week.

On October 8, 2026, researchers announced that the Solar Orbiter spacecraft — a joint ESA/NASA mission — had done something that looked impossible on paper. It flew directly through one of these magnetic anomalies, called a switchback, and fingerprinted the particles inside it. For the first time, scientists could trace where this bizarre solar feature actually originates.

And the answer changes how we understand the star our entire civilisation depends on.

What is a solar wind switchback?

Picture the Sun as a giant fan blowing a magnetic field outward in all directions. The solar wind is that stream — plasma and charged particles racing away from the Sun at 400 to 800 km/s. The magnetic field lines embedded in it should flow relatively smoothly outward.

They don't.

In 2019, NASA's Parker Solar Probe — the fastest object humanity has ever built — flew closer to the Sun than any spacecraft before it. What it found shocked the solar physics community. The magnetic field kept flipping backward. S-shaped kinks where the field suddenly reversed direction, then snapped forward again. Like a garden hose that doubles back on itself mid-flow, then straightens out — over and over, across hundreds of millions of kilometres of space.

Scientists named them switchbacks. They were everywhere. But nobody could agree on what created them, or where.

Here's what made switchbacks more than a curiosity: the Sun's surface — the photosphere — burns at around 5,500°C. But the corona, the wispy outer atmosphere you see glowing during a total solar eclipse, reaches one to three million degrees. The atmosphere is somehow hundreds of times hotter than the surface below it.

That's like standing next to a campfire and getting colder as you walk closer. Backward. Physically absurd. And these magnetic switchbacks might be carrying the energy that explains it.

What did Solar Orbiter actually do differently?

Parker Solar Probe is the daredevil — fast and close, going where no machine has gone before. Solar Orbiter, launched in 2020, took a different approach. It carries instruments that can analyse particle composition in extraordinary detail — essentially taking a chemical fingerprint of whatever it flies through.

Different regions of the Sun shed different kinds of particles. Coronal holes — dark, open patches on the solar disc — produce a fast, clean wind. Active regions near sunspot groups emit a heavier, compositionally richer stream. By measuring the ratio of specific ions inside a switchback, Solar Orbiter can work backward to determine which part of the Sun the structure originally came from.

On its latest pass, Solar Orbiter flew directly into the S-bend. It sampled the particles. It looked at the composition. And it traced the switchback back to a coronal jet — a small, violent magnetic reconnection event on the Sun's surface that had flung a loop of magnetic field backward into the outgoing wind.

This is the equivalent of sending a probe through a hurricane, sampling a single raindrop, and working out which specific cloud it fell from. Over a star, 150 million kilometres away.

Why were there two competing theories — and which one won?

For years, solar physicists were split between two explanations for switchbacks.

Theory one: switchbacks form near the Sun, in the lower corona, when magnetic reconnection events — essentially miniature magnetic explosions — fling field lines backward into the outgoing wind. They're born at the source and travel outward fully formed.

Theory two: switchbacks form far from the Sun, in the solar wind itself, through turbulence — like river eddies that build up naturally as the wind travels hundreds of millions of kilometres outward. They're not launched from the corona; they grow during transit.

The difference matters enormously. If they form near the Sun, they carry direct fingerprints of coronal physics — diagnostic clues about the explosive processes that might be driving the corona's impossible temperature. If they form far out, they're interesting, but less revelatory.

Solar Orbiter's latest data points toward a coronal origin. The particles inside this switchback carried the unmistakable chemical signature of a coronal jet — a small explosive event right at the Sun's surface. This S-bend wasn't grown gradually through turbulence. It was launched, fully formed, from the star itself.

To be fair: one flythrough establishes one data point. Scientists are rightly cautious. It's possible that multiple mechanisms create switchbacks in different solar wind regions — near-surface origin for some, in-transit turbulence for others. Future Parker and Solar Orbiter passes will test whether this origin story holds across different solar conditions.

Why does the solar corona stay so much hotter than the Sun's surface?

This is one of astrophysics' most enduring embarrassments. Basic thermodynamics says energy moves from hot to cold. As you move away from a heat source, things should get cooler. The Sun's surface is about 5,500°C. The corona — the layer above — should be cooler than that.

Instead it's a million degrees hotter. Sometimes three million degrees hotter in active regions.

The leading suspects are wave heating (magnetic Alfvén waves rippling up from below and depositing energy into the corona) and nanoflare heating (billions of tiny magnetic reconnection explosions on the surface, each too small to observe individually, but collectively depositing enormous energy). The coronal jets that Solar Orbiter's latest data implicates are the same class of event as nanoflares — small reconnection events, happening constantly across the entire solar disc.

This doesn't prove nanoflares heat the corona. But it does suggest that coronal reconnection events are more energetic, more pervasive, and more structurally significant than previously understood. They're not just heating the corona — they appear to be physically launching structure into the solar wind that we can still detect millions of kilometres away.

How does this affect Earth's satellites right now?

The solar wind isn't just a physics curiosity. It's the reason we have geomagnetic storms. It's why the operators of every satellite currently tracked live on SkyLens — all 15,968 of them — have to watch the Sun as closely as they watch the ground below.

When the solar wind intensifies and hits Earth's magnetosphere, it distorts the planet's magnetic bubble. Satellites in low Earth orbit experience increased atmospheric drag as the upper atmosphere expands — orbits decay faster, fuel burns faster, lifetimes shorten. During extreme solar storms, GPS signals get corrupted mid-flight. Power grids on the ground develop surging induced currents. The 1989 Quebec blackout that cut power to 6 million people for 9 hours? A solar storm did that — and the grid today is far more electronics-dependent than it was then.

Understanding switchbacks better means understanding what drives the solar wind's structure. Understanding that means better space weather forecasting. And better forecasting means earlier warnings before the next major storm — warnings that matter for satellite operators, airline pilots on polar routes, power grid managers, and ultimately anyone who uses GPS navigation to get home.

Want to understand how solar activity shapes every orbit above you right now? SkyLens has a deep-dive on space weather and orbital mechanics — because the Sun's behaviour and the health of every satellite in the sky are not separate stories.

What comes next for Solar Orbiter and Parker Solar Probe?

The two missions were designed to complement each other — one goes deep and fast, the other goes precise. Parker Solar Probe will keep tightening its spirals, eventually skimming just 6.9 solar radii from the Sun's centre — close enough that if you could stand on its heat shield, the Sun would fill the entire sky 22 times over. Solar Orbiter will keep building its library of particle fingerprints from different solar wind streams, different latitudes, different solar conditions.

Each pass adds a data point. Each data point makes the picture sharper. The mystery of what makes the corona so impossibly hot has been open since the 1940s. These two spacecraft are the most powerful tools we've ever aimed at it.

The Sun has been burning for 4.6 billion years. It's kept its secrets for most of that. But the gap is closing — one magnetic S-curve at a time. For more stories like this, explore the SkyLens blog.