As it circles closer to the solar surface, Parker is making new discoveries that other spacecraft were too far away to see. (Illustration: Nasa)
The Parker Solar Probe became the first human-made object to venture into the Sun’s atmosphere, known as the corona.
During the risky maiden flight, the spacecraft sampled particles and magnetic fields emerging from the Sun, which has always intrigued astronomers the world over. Being hailed on the same scale as the Moon landings, the probe’s arrival into the solar world is set to unravel unknown features about the biggest star in our solar system.
“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 impact on our solar system, but everything we learn about our own star also teaches us more about stars in the rest of the universe,” Thomas Zurbuchen, the associate administrator for the Science Mission Directorate at Nasa said.
WHAT IS THE PARKER SOLAR PROBE?
The Parker Solar Probe was launched in 2018 to explore the mysterious world of our Sun. Named after American solar astrophysicist Eugene Parker, the spacecraft is working to unravel the mysteries of our Sun.
It will fly through the Sun’s atmosphere as close as 3.8 million miles to our star’s surface, well within the orbit of Mercury and more than seven times closer than any spacecraft has come before.
The spacecraft will fly close enough to the Sun to watch the solar wind speed up from subsonic to supersonic, and it will fly through the birthplace of the highest-energy solar particles.
Nasa said that to perform these unprecedented investigations, the spacecraft and instruments are being protected from the Sun’s heat by a 4.5-inch-thick carbon-composite shield, which can withstand temperatures outside the spacecraft that reach nearly 1,377 degrees Celsius.
The close approach and venture into Sun’s atmosphere is set to provide critical new data that has remained elusive to astronomers so far including from within the solar wind the flow of particles from the Sun that can influence us at Earth.
The probe in 2019 discovered that magnetic zig-zag structures in the solar wind, called switchbacks, but how and where they form remained a mystery.
“Scientists are hopeful that with the distance decreasing after every flyby, Parker Solar Probe has now passed close enough to identify one place where they originate: the solar surface. Flying so close to the Sun, Parker Solar Probe now senses conditions in the magnetically dominated layer of the solar atmosphere the corona that we never could before.
“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,” Nour Raouafi, the Parker project scientist said.
As Parker Solar Probe ventures closer to the Sun, it’s crossing into uncharted regimes and making new discoveries. This image represents Parker Solar Probe’s distances from the Sun for some of these milestones and discoveries. (Photo: Nasa)
INTO THE EYE OF (SOLAR) STORM
During the first flyby, the Parker Solar probe passed into and out of the corona several times in April during the spacecraft’s eighth close approach to the sun. The spacecraft encountered the specific magnetic and particle conditions at 18.8 solar radii (around 8.1 million miles) above the solar surface that told scientists it had crossed the Alfvén critical surface for the first time and finally entered the solar atmosphere.
At one point, as Parker Solar Probe dipped to just beneath 15 solar radii (around 6.5 million miles) from the Sun’s surface, it transited a feature in the corona called a pseudostreamer. Pseudostreamers are massive structures that rise above the Sun’s surface and can be seen from Earth during solar eclipses.
The spacecraft found itself in a region where the magnetic fields were strong enough to dominate the movement of particles there. Nasa said that the first passage through the corona, which lasted only a few hours, is one of many planned for the mission.
The spacecraft will continue to spiral closer to the Sun, eventually reaching as close as 8.86 solar radii (3.83 million miles) from the surface. The next flyby of the Sun is scheduled for January 2022.
The timing of the flyby is just right as the Sun’s 11-year activity cycle the solar cycle ramps up. With the Sun waking up, the outer edge of the corona will expand, giving Parker Solar Probe a greater chance of being inside the corona for longer periods of time.