The Parker Solar Probe (PSP), built and operated by researchers at the Johns Hopkins University’s Applied Physics Laboratory (APL) in Laurel, has completed two initial flybys of the Sun and is already helping scientists gain insight into how other stars may form and behave throughout the universe.
Launched in August 2018, Parker has studied the Sun from a distance of about 15 million miles, closer than the planet Mercury, and will come even closer in the future.
Data gathered by Parker is being shared in four new papers, available online from the journal Nature. NASA also announced the initial findings of PSP during a teleconference on Dec. 4.
“Some of the information we found confirmed what we expected, but some of it is simply unexpected,” said Nicola Fox, director of the Heliophysics Division at NASA Headquarters.
Among the findings are new understandings of how the solar wind behaves. Seen near Earth, solar wind plasma appears to be a relatively uniform flow, but Parker’s observations reveal a more dynamic, highly structured system closer to its source.
Another goal of PSP is to better understand solar flares and mass ejections to help predict when these explosions might be directed toward Earth, improving the protection of astronauts, satellites and other technology in space.
According to Justin Kasper, principal investigator of PSP’s SWEAP instrument at the University of Michigan in Ann Arbor, scientists also want to understand what’s heating the solar corona up to millions of degrees, thousands of times hotter than the surface of the Sun, and what accelerates the solar wind to its high speeds.
One of the biggest surprises in PSP’s initial observations was the distance at which the solar wind still rotates under the sun’s influence, which proved to be 15 to 25 times larger than predicted.
“We’re clearly missing something fundamental in our models,” Kasper said, which could change the understanding of how stars lose angular momentum over time, meaning the Sun’s rotation could begin slowing down much faster than expected as it ages.
David McComas, principal investigator of the ISOIS instrument at Princeton, said PSP observed a very small, low-energy event a full day ahead of a small coronal mass ejection, a precursor that could equate to a lengthier advance warning of similar solar mass ejections in the future.
“Over the next few years we’re looking forward to getting closer to the Sun, near the sources of the heat, the acceleration of particles and the erupters,” Fox said.