Scientists Discovered Something We've Never Seen on the Sun, and It Could Explain a Lot

Scientists have discovered something we’ve never seen before on the Sun: a weird new class of jets on its surface that could help explain the mysterious origin of the solar wind, a stream of charged particles that exerts a huge influence over our planetary system, reports a new study. 

Solar Orbiter, a spacecraft launched by the European Space Agency in 2020, spotted small bursts of plasma near the Sun’s South Pole from a distance of just 28 million miles, which is closer than the orbit of Mercury. 

These newfound “picoflare jets” are a few hundred miles in scale and they fire for just 20 to 100 seconds, rendering them invisible to previous missions. But though they are tiny features relative to the Sun, their cumulative impact may seriously juice up the solar wind, a phenomenon that scientists have struggled to explain for decades.

The solar wind is made of charged particles, such as electrons and protons, that escape from the Sun’s outermost atmosphere, known as the corona, through holes that open in the solar magnetic field. These particles interact with solar system bodies, including Earth, and generate auroras, geomagnetic storms, and a range of other phenomena. But while the solar wind is an essential component of our local system, scientists are not sure what exact mechanisms underpin this prominent force.

Now, a team led by Lakshmi Pradeep Chitta, a solar physicist at the Max Planck Institute for Solar System Research, has discovered a missing piece of this puzzle in images captured by Solar Orbiter in March 2022. As the spacecraft made its close approach, it observed the picoflare jets inside a “coronal hole” on the Sun, which is an opening in the magnetic field that allows matter to escape. The team believes the jets could be an important driver of the solar wind, according to a study published on Thursday in Science.

“Coronal holes are areas on the Sun with open magnetic field lines,” Chitta and his colleagues in the study. “They are a source region of the solar wind, but how the wind emerges from coronal holes is not known.” 

“We observed a coronal hole using the Extreme Ultraviolet Imager on the Solar Orbiter spacecraft,” the researchers continued, noting that the jets reach speeds of about 60 miles per second and occupy the “picoflare” range of kinetic energy. “We suggest that such picoflare jets could produce enough high-temperature plasma to sustain the solar wind and that the wind emerges from coronal holes as a highly intermittent outflow at small scales.”

Scientists have long suspected that the solar wind is supercharged with matter that escapes from coronal holes, but getting a firmer read of this process required a closer look at an object that is infamously difficult to study: the Sun. Solar Orbiter is part of a new generation of sophisticated solar observatories, including NASA’s Parker Solar Probe and the Daniel K. Inouye Solar Telescope, that aims to stare down our star and extract some of its most persistent secrets, including the mechanics of the solar wind. 

The picoflare jets observed by Solar Orbiter appear to erupt when shifting magnetic field lines inside the corona suddenly “reconnect” in more stable configurations, an event that produces blinding jolts of light and energy. This is basically a smaller-scale version of the same “magnetic reconnection” that triggers solar flares and coronal mass ejections, which are tempestuous explosions on the Sun that can wreak havoc on spacecraft and electronic infrastructure here on Earth. 

Though picoflare jets have only been observed in one coronal hole, the eruptions could supply enormous amounts of charged material and heat to the solar wind, assuming they are present in holes across the Sun. Future observations may reveal more about these short-lived jets, and their role in the solar wind, revealing new insights about the radiant enigma at the center of our solar system.