On last December 24, 2024, NASA’s Parker Solar Probe accomplished an extraordinary feat by flying closer to the Sun than any man-made object in history. This mission, a collaboration between NASA and the Johns Hopkins Applied Physics Laboratory, will revolutionize our understanding of our star and its influence on the solar system.
At 6:53 a.m. Eastern time, the Parker Solar Probe passed within 3.8 million miles of the Sun’s surface, more than seven times closer than any previous mission. During this close encounter, the spacecraft will reach an astonishing speed of 430,000 miles per hour, shattering its own record as the fastest man-made object ever.
Dr. Nicky Fox, associate administrator for NASA’s Science Mission Directorate, emphasizes the importance of this mission: “It’s a voyage of discovery. We really are going into the unknown. Nothing has flown through the atmosphere of a star, and no other mission will for a long time“.
Since its launch in 2018, the Parker Solar Probe has completed 21 solar flybys, getting closer and closer to the sun with each pass. These perihelia have yielded remarkable science, captured stunning images, and even provided unexpected observations of Venus.
The 22nd encounter on December 24 was particularly special, as the spacecraft ventured hundreds of thousands of miles closer to the Sun than ever before. This took it well beyond the Alfvén surface, the boundary where the solar wind escapes into space, and into uncharted stellar territory.
Dr. Adam Szabo, a mission scientist at NASA’s Goddard Space Flight Center, explains the potential significance of this deeper dive: “Going deeper into that area of the Sun’s atmosphere could offer insights into the ‘interacting waves’ that ultimately may contribute to the solar wind’s acceleration out into the solar system“.
The timing of this close approach coincides with the Sun’s most active state, known as solar maximum. This increases the possibility of witnessing spectacular solar events at close range. The mission team is eagerly anticipating the chance to observe major solar phenomena such as coronal mass ejections, which could provide crucial data on the mechanisms that drive the solar wind and heat the Sun’s corona.
Dr. Nour Rawafi, project scientist at the Applied Physics Laboratory, shares the team’s excitement: “If the Sun gives us one of these huge explosions, like a coronal mass ejection, when Parker Solar Probe is very close to the Sun, that would be fantastic.“
Parker Solar Probe’s journey to the Sun is a testament to human ingenuity and perseverance. The concept of sending a spacecraft to study the Sun up close has been around since the dawn of the space age, but the technical challenges were immense. One major hurdle was the enormous amount of energy required to propel a probe toward the Sun.
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Dr. Yanping Guo, the mission’s design and navigation manager, came up with an innovative solution in 2007. The spacecraft’s trajectory includes seven gravitational tugs from Venus, allowing it to gradually approach the Sun while conserving fuel.
The mission was named after Eugene Parker, the solar physicist who predicted the existence of the solar wind in the 1950s. Dr. Parker lived to see the launch of his namesake spacecraft before passing away in 2022 at the age of 94.
The Parker Solar Probe has already made significant discoveries during its previous encounters with the Sun. One surprising finding was the presence of magnetic “switchbacks” that help drive the solar wind. The spacecraft also observed a dust-free zone near the Sun, confirming a 1929 prediction by astronomer Henry Norris Russell.
These discoveries have far-reaching implications, from protecting our civilization from dangerous space weather to assessing the potential for extraterrestrial life in other star systems. As Dr. Rawafi notes, the best may be yet to come: “I wish I could go back and be a kid and start all over again.”
The December 24 solar encounter marks a pivotal moment in solar science. As Parker Solar Probe plunges deeper into the Sun’s atmosphere, it will collect unprecedented data on the corona and the processes that drive solar activity.
This milestone builds on the spacecraft’s historic achievement in April 2021, when it became the first spacecraft to “touch” the Sun by crossing the Alfvén critical surface. This boundary marks the end of the Sun’s atmosphere and the beginning of the solar wind.
Dr. Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate, highlights the significance of this achievement: “Parker Solar Probe ‘touching the Sun’ is a monumental moment for solar science and a truly remarkable feat. Not only does this milestone provide us with deeper insights into our Sun’s evolution and its impacts on our solar system, but everything we learn about our own star also teaches us more about stars in the rest of the universe“.
The spacecraft’s unique vantage point allows it to make discoveries that other spacecraft orbiting farther from the Sun simply cannot. For example, Parker has revealed that the mysterious magnetic structures known as switchbacks are abundant near the Sun and emanate from its surface.
Dr. Nour Raouafi explains the unprecedented nature of these observations: “We see evidence of being in the corona in magnetic field data, solar wind data, and visually in images. We can actually see the spacecraft flying through coronal structures that can be observed during a total solar eclipse.“
As Parker Solar Probe continues its mission, scientists expect more groundbreaking discoveries. The spacecraft is scheduled to make additional close flybys of the Sun, potentially as close as 3.83 million miles from the surface.
Dr. Nicola Fox, division director of NASA’s Heliophysics Division, is optimistic about the mission’s future: “I’m excited to see what Parker finds as it repeatedly passes through the corona in the years to come. The opportunity for new discoveries is boundless“.
