NASA Records 19-Day Solar Radio Burst

NASA has recorded a solar radio burst lasting 19 days, the longest ever observed. The event took place between August 21 and September 9 2025 and exceeded the previous record of five days. When first detected the burst appeared routine but continued far longer than typical solar radio bursts which usually last only hours to a few days.

The burst is classified as a Type IV solar radio emission which is produced by reservoirs of electrons trapped within the sun's magnetic fields. These electrons generate radio waves as they move. Researchers determined that three coronal mass ejections from the sun filled the electron reservoir and sustained the burst for the extended period.

Radio Emission Linked to Potentially Disruptive Events

While the Type IV radio burst itself is harmless coronal mass ejections can release plasma and particles capable of affecting satellites spacecraft and other technology on Earth. The same magnetic environments that produce the radio waves can send particles toward the planet.

Such events can disrupt systems that modern infrastructure depends upon. To examine the burst researchers combined observations from four spacecraft positioned across the inner solar system. The missions included NASA's STEREO Parker Solar Probe and Wind as well as the jointly operated Solar Orbiter from the European Space Agency and NASA.

Each spacecraft captured portions of the 19-day event as the sun's rotation brought the source into view. Scientists developed a new tracking technique using data from the STEREO spacecraft. This allowed them to identify the burst's origin in a large magnetic structure known as a helmet streamer in the sun's outer atmosphere.

Helmet streamers are funnel-shaped features visible around the sun's edges during solar eclipses. The study was published in the Astrophysical Journal Letters. Researchers said the work is helping improve identification and tracking of solar radio bursts.

The findings are also expected to enhance space weather forecasting capabilities.