Parker Solar Probe has pulled back the curtains on the Sun’s dazzling corona in the past few years. It has revealed a new mystery that could fundamentally change our understanding of the star at the center of our Solar System. It’s a discovery that could help scientists rewrite their models to model space weather and our Sun’s role in the evolution of stars like ours.
The revelation came in a new study published in the journal Nature. Parker’s FIELDS instrument spotted “reversals” in the direction of the magnetic field embedded in the flow of solar wind that passes over the spacecraft. The events last seconds to minutes as they move over the spacecraft. They were not detectable at other times, either during the first 16 flybys or when analyzed from Earth, which is nearly 149 million kilometers (93 million miles) away.
As Parker continues to study the Sun, it will use encounters with Venus to leverage the planet’s gravity to slingshot itself closer and closer to our closest star. This will put it in a position to take advantage of future events at the Sun called perihelion when it gets as close to the surface of the Sun as it can get.
At its closest, Parker will be less than 7 million kilometers from the Sun’s surface – 6 times closer to it than the Helios probes that broke the previous record set in the 1970s. That will allow the spacecraft to see more of the corona’s wispy plasma and trace the energy that heats it. It will also explore why the corona is hotter than the Sun’s interior.
Scientists will be able to look at the corona in unprecedented detail, thanks to the spacecraft’s heat shield, which keeps its instruments above room temperature even when they are the closest the spacecraft can reach the Sun’s fiery surface. This will give them a clearer picture of the dynamics that drive the solar winds that blow away from the Sun and into the interstellar medium and the mechanisms that accelerate and transport energetic particles.
The results from the latest flyby will be added to Parker’s data archive and used to refine further the science goals for its next perihelion, scheduled to occur on Nov. 21, 2023. In that mission phase, Parker will make 24 passes of the Sun, racing through the corona at up to 250 times faster than a Lockheed Martin F-16 fighter jet. It will be the fastest spacecraft ever built and the closest to the Sun by far. This is part of a seven-year NASA mission to unravel the secrets of our nearest star. The mission is part of a more significant effort, known as Living With a Star, to understand our Sun’s effects on our planet and beyond.