Tiny, Explosive ‘Jetlets’ Might Be Fueling the Solar Wind

Streaming out of the sun at a million miles an hour, the solar wind—a blistering plasma of electrons, protons, and ions flowing through space—is a decades-old enigma. Scientists know it once stripped Mars of its atmosphere, and some think it put ice on the moon. Today, it causes the glimmering Northern Lights displays and messes with satellite communication systems. But researchers haven’t been able to nail down how the solar wind gets made, heats up to millions of degrees, or accelerates to fill the entire solar system. 

Now, a team of researchers think they’ve figured it out: The solar wind, they say, is driven by jetlets—tiny, intermittent explosions at the base of the sun’s upper atmosphere, or corona. The theory, which was just published in The Astrophysical Journal, emerged from data taken by NASA’s Parker Solar Probe, a car-sized satellite that has repeatedly flown by the sun since 2018. It measures properties of the solar wind and traces the flow of heat and energy in the outermost part of the sun’s atmosphere that begins about 1,300 miles above its…