The Parker Solar Probe has made its 14th close flyby of the Sun as part of its ongoing quest to unlock our star’s secrets.
Early in the morning of Sunday, December 11, the NASA spacecraft approached the closest point to the surface of the sun, also known as the photosphere, at a distance of about 5.3 million miles (8.5 million km). , braving intense radiation and intense heat to gather data about the atmosphere, the outermost part of the star, called the “halo” or “crown.”
Scientists have estimated the exact time of closest approach to the sun, or perihelion, to be around 8:16 a.m. EDT (1:16 p.m. GMT), as the spacecraft is traveling at a staggering speed of about 364.639 miles per hour (586.829 km /h). ). This speed is 200 times faster than a bullet fired from a pistol.
The Dec. 11 perihelion won’t be as close as the Parker Solar Probe, which was launched aboard a Delta 4 Heavy rocket from Cape Canaveral in August 2018.
During the next flyby, the spacecraft will advance towards the sun and eventually pass close to it, 6,115,500 km from the surface. It is seven times closer to the sun than any previous spacecraft and about 10 times closer to the sun than the planet Mercury, and the Parker Solar Probe will experience temperatures as high as 2,500 degrees Fahrenheit (1,400 degrees Celsius).
To withstand these extreme conditions, the spacecraft is equipped with a 4.5-inch (11.43 cm) thick carbon composite shield that maintains its scientific payload at room temperature.
One of the Parker Solar Probe’s main goals is to study the corona, the outermost layer of the sun’s atmosphere, and gather data that can help solve one of the sun’s oldest mysteries: why the sun’s atmosphere is hotter than its surface. ?
Theories of stellar physics indicate that pressure increases deeper within the star’s plasma, and the star becomes hotter. But Halo challenges that theory. Though fragile and diffuse, the plasma in this layer is much hotter than the plasma on the Sun’s surface, the photosphere below the corona.
Temperatures in the corona are 2 million Fahrenheit (1.1 million degrees Celsius) and higher, and despite the fact that 1,000 miles (1,600 kilometers) below them, the photosphere is 10 million times denser and reaches temperatures up to 10,000 Fahrenheit (5,500 degrees Celsius) .
The corona is difficult to study from Earth because the light it emits dims the brighter light from the photosphere, meaning the corona is only visible during a total solar eclipse, when the moon blocks light from the photosphere (scientists can also use special tools to replicate the effect).
Hence the need for the Parker Solar Probe to be “close” to our star to better understand the corona, which is also responsible for the release of the solar wind, a stream of charged particles that here can interfere with communications and energy infrastructure on earth .
Since the sun is the only star close enough to be studied in this way, learning more about it will also help scientists understand much more distant stellar objects.
The solar probe will reach its next fifteenth close to the sun on March 17, 2023, and will also reach about 5.3 million miles (8.5 million kilometers) above the sun’s surface.
Later in the year, the spacecraft will swing close to Venus to adjust its trajectory near the sun as the mission comes to an end in 2025, having completed 24 scheduled flybys of the sun during the mission.
