NASA’s Parker solar probe is the first to “touch” the Sun

(CNN) — Sixty years after NASA set the goal, and three years after the launch of its Parker Solar Probe, the spacecraft has become the first to “touch the sun.” The Parker solar probe has successfully flown through the solar corona, or upper atmosphere, to sample particles and magnetic fields from our star.

“Parker Solar Probe ‘touching the Sun’ is a monumental moment for solar science and a truly remarkable feat,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate, in a statement.

“This milestone not only provides us with a deeper understanding of the evolution of our Sun 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 announcement was made at the 2021 American Geophysical Union Fall Meeting in New Orleans this Tuesday, and the solar landmark research was published in Physical Review Letters.

Parker Solar Probe launched in 2018 and set out to circle ever closer to the sun. Scientists, including the spacecraft’s namesake astrophysicist Eugene Parker, want to answer fundamental questions about the solar wind that rises from the sun and spews energetic particles through the solar system.

This illustration shows the Parker solar probe reaching the outer atmosphere of the sun (NASA)

The sun’s corona is much hotter than the actual surface of the star, and the spacecraft might give us an idea why. The corona is one million Kelvin (1,800,000 degrees Fahrenheit) at its hottest, while the surface is around 6,000 Kelvin (10,340 degrees Fahrenheit).

The spacecraft has already revealed surprising findings about the sun, including the discovery in 2019 of zig-zag magnetic structures in the solar wind called curves.

Now, thanks to Parker’s latest approach to the sun, the spacecraft helped scientists determine that these changes originate on the solar surface.

Before the Parker Solar Probe mission is completed, it will have made 21 close approaches to the sun over the course of seven years. The probe will orbit 3.9 million miles from the sun’s surface in 2024, closer to the star than Mercury, the closest planet to the sun.

Although that sounds far away, the researchers compare it to the probe located on the four-yard line of a soccer field and the sun as an end zone.

When they are closer to the sun, the 4½-inch-thick carbon composite solar shields will have to withstand temperatures close to 2,500 degrees Fahrenheit. However, the interior of the spacecraft and its instruments will remain at a comfortable room temperature.

“Flying so close to the Sun, Parker Solar Probe now detects conditions in the magnetically dominated layer of the solar atmosphere, the corona, that we have never been able to before,” said Nour Raouafi, Parker project scientist at the Johns Hopkins Laboratory of Applied Physics in Laurel, Maryland, in a statement.

“We see evidence of being in the corona in magnetic field data, solar wind data, and visually in imagery. In fact, we can see the spacecraft flying through coronal structures that can be observed during a total solar eclipse.”

Approaching a star

In April, Parker’s team realized that their spacecraft had crossed the boundary and entered the solar atmosphere for the first time.

It occurred as the spacecraft made its eighth flyby of the sun and recorded specific particle and magnetic conditions of a boundary where the sun’s massive solar atmosphere ends and the solar wind begins: 8.1 million miles above the sun’s surface.

“We fully expected that sooner or later we would meet the crown for at least a short period of time,” said Justin Kasper, lead author of the study, professor at the University of Michigan and deputy director of technology at BWX Technologies, Inc. in a statement. “It is very exciting that we have already reached it.”

Parker went in and out of the corona several times over the course of a few hours during the April flyby, helping researchers understand that the boundary, called the Alfvén critical surface, is not a uniform circle around the sun. Instead, it has peaks and valleys. Understanding the presence of these features could allow scientists to compare them with solar activity on the sun’s surface.

During the flyby, Parker had another intriguing encounter while passing 6.5 million miles from the sun’s surface. It passed through a feature called a pseudostreamer, a large structure that rises above the surface of the sun that has been observed from Earth during solar eclipses.

Parker Solar Probe witnessed these streamers while flying through the crown earlier this year.

When the spacecraft flew through the pseudostreamer, things were quiet, like in the eye of a storm. Typically Parker is bombarded with particles while flying through the solar wind. In this case, the particles moved more slowly and the zigzag curves decreased.

The spacecraft is likely to pass through the corona again in January during its next flyby.

“I am excited to see what Parker encounters as he repeatedly passes through the crown in the coming years,” Nicola Fox, divisional director of NASA’s Heliophysics Division, said in a statement. “The opportunity for new discoveries is limitless.”

Parker is likely in the right place at the right time during future flybys, as the sun’s 11-year cycle intensifies with activity in the coming years. Every 11 years, the sun completes a solar cycle of calm and stormy activity and begins a new one.

Understanding the solar cycle is important because space weather caused by the sun (flares such as solar ones and coronal mass ejection events) can affect the power grid, satellites, GPS, airlines, rockets, and astronauts in space. .

The newest solar cycle, which began in December 2019, is predicted to peak in July 2025, signifying an increase in solar activity.

This means that the outer edge of the solar corona will expand and Parker will likely spend more time flying through the sun’s mysterious outer atmosphere.

“It’s a really important region to go into because we think all kinds of physics are potentially activated,” Kasper said. “And now we are entering that region and hopefully we will start to see some of these physics and behaviors.”