Scientists have created the first detailed maps of the sun’s outer atmosphere, where solar material breaks free and streams into space. Using data from NASA’s Parker Solar Probe and distant spacecraft, these maps reveal that this boundary grows larger and more chaotic during periods of high solar activity, marked by increased sunspots and solar flares.
Published recently in The Astrophysical Journal Letters, these findings help refine our understanding of space weather, which affects everything from our communications to power grids. Lead author Sam Badman from Harvard & Smithsonian noted, “Before, we had to guess about the sun’s boundary. Now, we have an accurate map to guide our studies.”
This boundary, called the Alfvén surface, marks where the solar wind accelerates past magnetic waves that try to pull particles back to the sun. Beyond this point, solar particles are lost to space permanently. Researchers previously knew that this boundary shifts with the sun’s roughly 11-year activity cycle, expanding during solar maxima and contracting during solar minima. Now, they can confirm these changes with direct observations.
The Parker Solar Probe made close passes through the sun’s outer atmosphere, gathering data that confirms where the sun’s influence ends and the solar wind begins. Co-author Michael Stevens added, “This research shows that Parker is diving deep into the region where the solar wind is born.”
Understanding how and where solar wind escapes is critical. It could answer key questions about why the sun’s corona becomes hotter as it moves away from the surface. This insight is vital for improving space weather forecasts, protecting astronauts and technology on Earth from solar storms.
In the next solar minimum, the Parker Solar Probe will return to study these boundaries further, allowing scientists to observe their evolution throughout a complete solar cycle. Stevens emphasized, “We still have many questions about the sun’s corona that need answers.” As we dive deeper into these mysteries, we enhance our understanding of our star and its impact on our solar system.
For detailed insights on space weather dynamics, you can refer to reliable sources like NASA or the National Oceanic and Atmospheric Administration (NOAA).
