'Humanity Has Touched the Sun'

A NASA spacecraft has officially "touched" the sun, plunging through the unexplored solar atmosphere known as the corona. 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; they made the announcement Tuesday during a meeting of the American Geophysical Union. "We have finally arrived," said NASA heliophysics director Nicola Fox, per Nature. "Humanity has touched the Sun."

Launched in 2018, Parker was 8 million miles from the center of the sun when it first crossed the jagged, uneven boundary between the solar atmosphere and outgoing solar wind known as the Alfvén surface. The BBC offers a definition: "It is the point where solar material that is normally bound to the Sun by gravity and magnetic forces breaks free to stream out across space." The spacecraft dipped in and out of the corona at least three times, its instruments safeguarded by a carbon-composite heat shield. (NASA has a great explanation here of why the spacecraft won't melt.)

"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 per second. The corona appeared dustier than expected, according to project scientist Nour Raouafi of Johns Hopkins University, per the AP. Future coronal excursions will help scientists better understand the origin of the solar wind, he said, and how it is heated and accelerated out into space.

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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. (More NASA stories.)