The American space agency NASA says a spacecraft has entered the sun's outermost atmosphere for the first time. Scientists announced that Parker Solar Probe traveled through the solar atmosphere's outer edge, known as the corona (日冕). They described the entry as a successful touch on the sun.
Unlike Earth, the sun does not have a solid surface. Instead, it is a superheated ball of material held
together by gravity and magnetic ( 磁 的 ) forces. The temperature of the corona is so high that the sun's gravity cannot hold on to it and some solar material escapes from it and goes into space, which causes the solar wind. The solar wind is the flow of charged pieces, known as plasma.
Parker Solar Probe was launched in 2018 which mainly studied the solar wind. The sun is actually a magnetic variable star with solar activity happening nearly periodically. Scientists said being able to study the solar wind and the corona close up could help them better understand "the way the activity causes changes to the planet we live on".
"We can actually see the spacecraft flying through the coronal structure during a total solar eclipse (日全食)," Nour Raouafi, the project scientist, said, adding that it took them a few months to examine information from the spacecraft and to confirm the result and that the evidence used included data on magnetic fields and the solar wind, as well as images. Scientists reported Parker Solar Probe successfully went in and out of the corona at least three times.
The Parker team said early data also suggested the spacecraft may have entered the corona during its ninth close approach in August, but a further study is needed to make a confirmation. The spacecraft is expected to keep getting closer to the sun and diving deeper into the corona until its final orbit, planned for 2025.
