In a groundbreaking discovery, scientists have observed a mesmerizing display of radio waves resembling the Northern Lights on Earth, known as auroras, occurring on the surface of the sun. This captivating solar lightshow unfolded approximately 25,000 miles above a sunspot, a magnetic dark area on the sun’s surface. This marks the first time such a phenomenon has been observed on our own sun.
Astronomers, based on Earth, detected these bursts of radio waves over the course of a week. Unlike typical transient solar radio bursts lasting minutes or hours, this discovery is described as “quite unlike” anything seen before, with the potential to reshape our understanding of magnetic processes on stars. The findings were published in the journal Nature Astronomy on November 13.
On Earth, auroras result from energetic solar debris interacting with the atmosphere near the poles, where the protective magnetic field is weaker. This interaction causes oxygen and nitrogen molecules to release energy in the form of light, creating the beautiful and colorful displays seen in the night sky.
Solar debris is usually ejected from the sun when magnetic fields around sunspots become tangled and then suddenly snap. This release of energy leads to solar flares and explosive jets of solar material, known as coronal mass ejections (CMEs).
By pointing a radio telescope at a sunspot on the sun’s surface, researchers detected an aurora-like emission above it. They believe this emission is caused by electrons from solar flares being accelerated along the sunspot’s powerful magnetic field lines. Unlike Earth’s auroras, these sunspot aurora emissions occur at much higher frequencies due to the sunspot’s magnetic field being thousands of times stronger than Earth’s.
The scientists express excitement about this discovery, as it introduces new avenues for studying the sun’s activity. They have already started examining archival data to uncover hidden evidence of past solar auroras. The research not only enhances our understanding of our own sun but also opens doors to studying stars beyond our solar system.
The researchers are in the early stages of assembling the puzzle of how energetic particles and magnetic fields interact, especially in the presence of long-lasting sunspots. This knowledge has broad implications, not only for understanding our sun but also for gaining insights into the activities of stars far beyond our solar system.
