Scientists Unveil the Secrets of the Sun's 'Point of No Return'
December 16, 2025258 VuesTemps de lecture: 2 minutes
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Astronomers have created the first accurate maps of the outer boundary of the solar atmosphere, known scientifically as the Alfvén surface. This boundary marks the point where solar material transitions from being influenced by the sun's magnetic field to freely flowing into space, forming what is referred to as solar wind.
A Dynamic Map of the Sun
Researchers utilized direct measurements from NASA's Parker Solar Probe along with data from other spacecraft, revealing that these boundaries are not static but rather dynamic, fluctuating with the sun's activity.
Sam Badman, an astrophysicist at the Harvard-Smithsonian Center and lead author of the study, stated: "For the first time, we have an accurate map that can serve as a navigation guide in this critical region. We can now monitor transformations in real-time and compare them to direct measurements, deepening our understanding of processes around the sun."
Boundary Changes with Solar Activity
As the sun approaches the peak of its 11-year activity cycle, the solar boundaries expand, becoming more rugged and irregular, while smoothing out during solar calm periods. This discovery allows scientists to refine their models for predicting solar storms, which can disrupt electrical grids on Earth and threaten the safety of astronauts and satellites.
Insights into Other Stars
The research also suggests that these findings could be used to understand the behavior of atmospheres around other stars in our galaxy. Through repeated passes of the Parker Solar Probe through the outer solar atmosphere and utilizing the specialized SWEAP instrument, scientists have obtained direct samples from the region beneath the Alfvén surface, accurately determining where and when solar winds escape the sun's magnetic grip.
The Next Steps in Solar Study
Research teams plan to return the Parker Solar Probe during the next solar calm period, allowing them to observe the solar boundary transformations throughout an entire solar cycle. Scientists hope this study will help solve one of the most complex mysteries of solar physics:
> Why does the solar corona become hotter as one moves away from its surface?
A Dynamic Map of the Sun
Researchers utilized direct measurements from NASA's Parker Solar Probe along with data from other spacecraft, revealing that these boundaries are not static but rather dynamic, fluctuating with the sun's activity.
Sam Badman, an astrophysicist at the Harvard-Smithsonian Center and lead author of the study, stated: "For the first time, we have an accurate map that can serve as a navigation guide in this critical region. We can now monitor transformations in real-time and compare them to direct measurements, deepening our understanding of processes around the sun."
Boundary Changes with Solar Activity
As the sun approaches the peak of its 11-year activity cycle, the solar boundaries expand, becoming more rugged and irregular, while smoothing out during solar calm periods. This discovery allows scientists to refine their models for predicting solar storms, which can disrupt electrical grids on Earth and threaten the safety of astronauts and satellites.
Insights into Other Stars
The research also suggests that these findings could be used to understand the behavior of atmospheres around other stars in our galaxy. Through repeated passes of the Parker Solar Probe through the outer solar atmosphere and utilizing the specialized SWEAP instrument, scientists have obtained direct samples from the region beneath the Alfvén surface, accurately determining where and when solar winds escape the sun's magnetic grip.
The Next Steps in Solar Study
Research teams plan to return the Parker Solar Probe during the next solar calm period, allowing them to observe the solar boundary transformations throughout an entire solar cycle. Scientists hope this study will help solve one of the most complex mysteries of solar physics:
> Why does the solar corona become hotter as one moves away from its surface?
