The Parker Solar Probe has become the first spacecraft to “touch the sun,” sixty years after NASA set the aim and three years after it launched. The Parker Solar Probe has completed a successful flight through the sun’s corona, or upper atmosphere, collecting particles and magnetic fields. On Tuesday, the news was made at the American Geophysical Union’s Fall Meeting in New Orleans, and research from the solar milestone was published in Physical Review Letters. The Parker Solar Probe was launched in 2018 with the goal of getting closer to the sun. Scientists, notably Eugene Parker, the spacecraft’s namesake astrophysicist, want to learn more about the solar wind, which blows out from the sun and flings energetic particles across the solar system.
The sun’s corona is far hotter than the star’s real surface, and the spacecraft may be able to explain why. At its hottest point, the corona reaches one million degrees Kelvin (1,800,000 degrees Fahrenheit), while the surface is roughly 6,000 degrees Kelvin. The spacecraft has already made some surprise discoveries about the sun, such as the discovery of switchbacks, or magnetic zig-zag patterns in the solar wind, in 2019. Parker’s most recent close encounter to the sun has now assisted scientists in determining that these switchbacks originate on the solar surface.
The spacecraft’s interior and instruments, on the other hand, will remain at a comfortable room temperature. Parker’s team discovered their spacecraft had passed the boundary and entered the solar environment for the first time in April. It happened when the spacecraft made its eighth flyby of the sun and recorded magnetic and particle conditions particular to a boundary 8.1 million miles above the sun’s surface where the enormous solar atmosphere ends and the solar wind begins. During the April flyby, Parker weaved in and out of the corona numerous times over the course of a few hours, revealing that the barrier, known as the Alfvén critical surface.