Quoted from the science.nasa.gov page, Wednesday (12/15/2021), this achievement has been long awaited and actually happened in April, but was only announced on December 14, 2021. This is a big achievement for Parker Solar Probe, a spacecraft that flies closer to the Sun than any mission in history.
“We have finally arrived. Humanity has touched the Sun,” said Nicola Fox, Director of NASA’s Heliophysics Division, based in Washington DC, as quoted by SINDOnews from the nature page, Wednesday (15/12/2021). (Read also; Photographed from a distance of 1 million miles, this is how Antarctica looks like during a solar eclipse )
The Parker Solar Probe spacecraft crossed the Sun’s atmosphere at 09:33 Universal Time on April 28, 2021. It took several months for mission scientists to download and analyze the data it collected, including to confirm that the spacecraft did indeed cross the defined boundary, known as the Alfven surface.
This Alfven surface marks the interface between the Sun’s atmosphere and the region of space dominated by the solar wind. The spacecraft crosses the Alfvén boundary when it is about 14 million kilometers, or just under 20 solar radii, from the Sun’s surface.
Since launching in 2018, the Parker Solar Probe has been orbiting the Sun and rotating closer and closer to the Sun’s surface with each pass. The carbon-composite heat shield is able to keep the instrument inside from overheating up to 1,370 degrees Celsius. (Read also; Archaeologists Find the Lost Temple of the Sun in Egypt )
This new milestone marks a major step for the Parker Solar Probe and a giant leap for solar science. This success helps scientists uncover information and understand how the Sun was formed and what materials make it up.
The most important thing is how the Sun is the closest star to the planet Earth. The paper describing the discovery is published in Physical Review Letters1. (Read also; NASA Spacecraft Sets Record for Closest Distance from the Sun )
The Parker Solar Probe is a rival to NASA’s Voyager twin spacecraft. In 2012, Voyager 1 traveled so far from the Sun that it became the first mission to leave a region of space dominated by the solar wind, a flood of energy particles emanating from the Sun.
In contrast, the Parker Solar Probe probe is flying ever closer to the heart of the Solar System, straight into the solar wind and into its atmosphere. Through the Parker Solar Probe, scientists can explore the Sun and find out the biggest unanswered questions about the Sun.
For example, how the sun produces wind and how its corona heats up to more extreme temperatures than on the surface of the sun. “This is a huge milestone,” said Craig DeForest, a solar physicist at the Southwest Research Institute in Boulder, Colorado.