NASA’s Parker Solar Probe was launched into space in August 2018 from Cape Canaveral, Florida, with the goal of touching the Sun. Having spent the last few years spiraling closer to our star, the spaceship has now arrived at its destination. The Parker Solar Probe is literally touching the Sun, which is amazing since it is a dream come true for everyone involved.
What does it mean to come into contact with the Sun? In order to answer this question, we must first examine the structure of the Sun. Our Sun, in contrast to the Earth, does not have a solid surface. It’s a massive ball of heated plasma that’s held together by the force of gravity in which it exists. Solar material is emitted from the surface of the sun. However, as it orbits the Sun, it is confined by the gravity and magnetic field of the Sun. The corona is made up of this material, which is responsible for the formation of the Sun’s atmosphere.
Eventually, some of this hot and rapid solar material manages to elude the Sun’s gravitational influence and erupts into space in the form of the solar wind. The Alfvén critical surface is a barrier that marks the outermost frontier of the Sun’s atmosphere. We were unsure of the precise location of this boundary. However, for the first time in history, a spaceship has successfully traversed it. The Parker Solar Probe traveled into the corona, where it came into contact with solar material that was still linked to the Sun. Most of the time, the wispy corona is too weak to be seen, but during total solar eclipses, the corona is clearly visible.
During solar eclipses, we’ve been studying the Sun’s atmosphere for centuries because it’s critical to understanding how our star effects life on Earth and the rest of the solar system. However, there is still much that is unknown about the corona.
Two of the most difficult scientific questions in astrophysics occur in an area known as the solar corona, which is where the sun’s magnetic field is strongest. The temperature of the corona is the first enigma, and the corona is approximately 300 times hotter than the photosphere, which is the visible surface of the Sun below.
The solar wind, which is a continuous stream of particles emanating from the Sun, is the second factor to consider. It accelerates out of the corona at speeds of up to millions of miles per hour, and we have no idea how it does it. Solar wind has the potential to interfere with our satellites and technologies. We must get to where the solar wind originates — the corona — in order to properly protect them.
As a result, getting there has been a crucial goal of NASA’s for quite some time. We originally proposed sending a spacecraft to the Sun in 1958, but we didn’t have the technology to make it through the mission until the 2000s, when we finally did. Parker has been on a collision course with our star since its inception in 2018. Once the spacecraft entered the corona in April 2021, it was around 20 solar radii away from the Sun’s surface, or approximately 8 million miles away, during Parker’s eighth orbit. This is a significant achievement, and it has taken us more than six decades to reach this stage.
The WISPR sensor on Parker’s spacecraft captured photographs as the spacecraft entered the corona. Spacecraft was encircled by streams of plasma, and Parker’s other equipment noticed a shift in the magnetic field surrounding the spacecraft.
Solar wind erupts from the Sun’s outer corona, hurling solar material out at tremendous speeds and preventing it from returning to the Sun’s surface. Solar material moves more slowly and is bound to the Sun when it enters the corona, where the Sun’s magnetic field becomes much stronger. It is formed by massive fluxes of plasma going out of the corona, which results in the bumpy ridges. Parker discovered that the boundary between these two sides is wrinkled rather than smooth, as opposed to the smooth separation that was expected. Massive fluxes of plasma going out of the corona are responsible for the formation of these rough ridges.
Scientists are baffled as to why this is happening, but as Parker comes closer, we’re uncovering more evidence. In the days before hitting the corona, Parker noticed kinks in the solar wind, when the solar wind would momentarily reverse direction. Switchbacks are the aspects of the solar wind that scientists have named. No one, however, knew how or where they came to be.
Finally, in 2021, the spacecraft was able to trace switchbacks back to one of their sources. As Parker moved closer to the Sun, it began to detect bursts of switchbacks, which scientists were able to trace back to the visible surface of the Sun, according to NASA.
The sun is made up of different cells. As heat rises beneath the surface of the earth, these convection cells churn and generate funnels of magnetic energy above the surface of the earth. According to the findings of the scientists, switchbacks form within these funnels before rising into the corona and beyond. This is simply one piece of the puzzle of the switchbacks, and it is still unclear how they came to be.
Parker will continue to seek for clues as it studies our Sun, which is the only star that we can observe up close for the next many years. It is also important to recognize that the Sun may be the only star known to support life, which is important as we seek for life outside of our solar system. That will go directly to the question of whether or not we are alone in this universe. In fact, it is one of the most difficult problems that humanity has yet to address.