The Sun is not known for being quiet.

It blasts out energy equivalent to 100 billion nuclear bombs every single second, routinely hurls billion tonne clouds of magnetized plasma into space, and occasionally treats us to auroras visible as far south as my home in Norfolk, UK.

But even by the Sun’s own extraordinary standards, something that began on an unremarkable day in August 2025 turned out to be genuinely remarkable – and it took a small fleet of spacecraft spread across the inner solar system to piece together what had actually happened.

It started with a Type IV radio burst.

These are bursts of radio waves produced when electrons get trapped inside the Sun’s magnetic fields, swirling around and releasing energy as they go.

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They happen reasonably regularly, typically lasting a few hours to a couple of days, and while the radio waves themselves are harmless, the magnetic environments that produce them are not.

The very same regions can also launch dangerous particle storms capable of damaging satellites and disrupting spacecraft.

This one, however, didn’t stop.

Days passed. Then more days.

When it finally ended, the radio burst had lasted 19 days, that’s nearly four times longer than anything previously recorded. The previous record holder had only managed five days.

To work out what was going on, researchers combined data from four different spacecraft: NASA’s STEREO, Parker Solar Probe, and Wind missions, alongside ESA and NASA’s Solar Orbiter.

The Sun Just Did Something Nobody Expected And It Kept Going For 19 Days
Parker Solar Probe mated to its third stage rocket motor before observing the record breaking solar event. (NASA/Johns Hopkins APL/Ed Whitman)

Each spacecraft caught the burst for a few days over its duration as the Sun’s rotation slowly carried the source region in and out of view of each probe, a bit like relay runners passing a baton across the Solar System.

No single spacecraft could see the whole event. It took all of them together to build the full picture.

Using a new analysis technique applied to STEREO data, the team managed to pinpoint the burst was coming from a large magnetic structure in the Sun’s outer atmosphere called a helmet streamer.

The Sun Just Did Something Nobody Expected And It Kept Going For 19 Days
This image taken during a 2017 total solar eclipse shows the classic V-shape of a large helmet streamer. (Miloslav Druckmüller, Peter Aniol, Shadia Habbal/NASA Goddard, Joy Ng)

The name sounds oddly medieval for something 150 million kilometers away, but it describes a distinctive V-shaped feature visible during solar eclipses, where magnetic field lines arch up from the Sun’s surface and stretch outward into space.

They are regions of concentrated magnetic activity, and this one had been supercharged by a series of three coronal mass ejections from the same area in quick succession effectively feeding the magnetic trap and keeping it energized far beyond its normal lifespan.

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Understanding what makes solar radio bursts like this persist for days or weeks while others fizzle out quickly is directly relevant to space weather forecasting, our ability to predict when the Sun is about to throw something dangerous in our direction.

Related: A Hidden Shift Inside The Sun Could Help Explain Weak Solar Cycles

The more accurately we can identify these features and understand their behavior, the better protected our satellites, astronauts, and ground-based infrastructure will be.

A paper describing the record-breaking radio burst was published in The Astrophysical Journal Letters.

This article was originally published by Universe Today. Read the original article.