Christmas present from the sun
Probe flies spectacularly close to our star
Updated on December 23, 2024 – 12:58 p.mReading time: 3 min.
At Christmas, a space probe flies deep into the sun’s atmosphere and reaches unexplored regions. Astronomers are eagerly awaiting the first signals.
A space probe flies through the solar atmosphere and comes closer to the sun than any man-made object before, right on Christmas. According to calculations by the US space agency NASA, its “Parker Solar Probe” probe comes within around six million kilometers of the surface of the sun – a record.
The rendezvous between the probe and the sun on December 24th around 1 p.m. our time was initially impossible for anyone to notice, “since we have no radio contact with the probe at that time,” says astrophysicist Volker Bothmer from the University of Göttingen.
The research team only expects a signal on the night of December 27th – assuming everything went well. “The probe then sends a sign of life to Earth.” This happens via a short, autonomous radio signal, comparable to the flashing of a lighthouse.
The first data will be available from the end of January, when the probe’s main antenna points towards Earth. “But it will take a few years until we have evaluated and understood all the data.” Bothmer leads the German participation in the mission and, among other things, helped develop its concept and a wide-angle camera.
The probe, which is the size of a small car, has a speed of around 690,000 kilometers per hour at its planned point closest to the sun and can withstand temperatures of around 1,000 degrees Celsius, writes NASA. This means it flies faster than any other object built by humans to date. However, if their 11.4 centimeter thick carbon heat shield were to shift even slightly, Bothmer says a large proportion of the instruments, including the camera developed with German help, would burn up.
Among other things, the researchers expect to find out why the sun’s outer atmosphere is many times hotter than its surface. This could shed more light on how the atmospheres of other stars work. “We don’t know exactly what Christmas presents the sun is giving us,” says Bothmer. But he expects surprises. There are numerous questions: How are the solar currents generated in the atmosphere? How do solar wind or solar storms form?
The “Parker Solar Probe” probe is not the first man-made visitor to the sun: the German-American probes “Helios 1” and “Helios 2” were launched in the 1970s, but at around 45 million kilometers they kept a reasonable distance from the heat ball .
The “Parker Solar Probe” probe, which was launched in August 2018 and weighs around 700 kilograms, has so far orbited the sun in highly elliptical orbits and therefore alternates between being near and far from the sun. According to NASA, on its first flyby in October 2018 it came closer to the sun than any other spacecraft before, at 42.7 million kilometers.
In 2021, it became the first probe to fly through the outermost layer of the sun’s atmosphere – called the corona. “For the first time in history, a space probe has touched the sun,” NASA wrote at the time. In 2023 it even came within a little more than 7 million kilometers of the sun’s surface.
According to Bothmer, the proximity of around six million kilometers means an even deeper immersion into the solar corona. “This will give us data from areas of the solar atmosphere that have never existed before. In this proximity we will then find ourselves in the birth regions of the solar wind and solar storms.”
For comparison: the Earth is on average around 150 million kilometers away from the Sun, and the closest planet to the Sun, Mercury, is around 58 million kilometers away.
After approaching the sun on December 24th, the space probe will probably continue to fly on the same elliptical orbit and will approach the star again on March 22nd and June 19th at a distance of around six million kilometers, says Bothmer. What will happen after that is currently being discussed: “We hope that we can continue to work with the Parker Solar Probe for many more years.”