Cape CanaveraL, Florida: A Nasa spacecraft has officially “touched’’ the sun, plunging through the unexplored solar atmosphere known as the corona.
Scientists announced the news on Tuesday during a meeting of the American Geophysical Union.
The Parker Solar Probe actually flew through the corona in April during the spacecraft’s eighth close approach to the sun. Scientists said it took a few months to get the data back and then several more months to confirm.
“Fascinatingly exciting,’’ said project scientist Nour Raouafi of Johns Hopkins University.
Launched in 2018, Parker was 8 million miles (13 million kilometers) from the centre of the sun when it first crossed the jagged, uneven boundary between the solar atmosphere and outgoing solar wind. The spacecraft dipped in and out of the corona at least three times, each a smooth transition, according to scientists.
“The first and most dramatic time we were below for about five hours ... Now you might think five hours, that doesn’t sound big,” the University of Michigan’s Justin Kasper told reporters. But he noted that Parker was moving so fast it covered a vast distance during that time, tearing along at more than 62 miles (100 kilometers) per second.
The corona appeared dustier than expected, according to Raouafi. Future coronal excursions will help scientist better understand the origin of the solar wind, he said, and how it is heated and accelerated out into space. Because the sun lacks a solid surface, the corona is where the action is” exploring this magnetically intense region up close can help scientists better understand solar outbursts that can interfere with life here on Earth.
Preliminary data suggest Parker also dipped into the corona during its ninth close approach in August, but scientists said more analyses are needed. It made its 10th close approach last month.
Parker will keep drawing ever closer to the sun and diving deeper into the corona until its grand finale orbit in 2025.
The latest findings were also published by the American Physical Society.
Box The new milestone marks one major step for Parker Solar Probe and one giant leap for solar science, NASA said, adding that it will help scientists uncover critical information about our closest star and its influence on the solar system.
The first-ever passage through the corona at 4.89 million miles lasted only a few hours. It is also one of many planned for the mission.
Launched in 2018 to explore the mysteries of the Sun, the Parker Solar Probe has, so far, completed nine full orbits of the Sun.
Before its prime mission ends in 2025, it will complete another 15 orbits.
It is expected to spiral closer to the Sun in January, eventually reaching as close as 3.83 million miles from the surface.
During its eighth flyby of the Sun in April, the spacecraft encountered the specific magnetic and particle conditions at around 8.1 million miles above the solar surface that told scientists it finally entered the solar atmosphere.
In 2019, Parker discovered that magnetic zig-zag structures in the solar wind, called switchbacks, are plentiful close to the Sun. But how and where they form remained a mystery. Halving the distance to the Sun since then, Parker Solar Probe has now passed close enough to identify one place where they originate: the solar surface.
