New observations from the European Solar Orbiter spacecraft reveal a continuous connection of small magnetic field lines on the Sun.
According to the European Space Agency (ESA), this connectivity may be part of the reason why some areas of the Sun are much hotter than others.
The surface of the Sun has a temperature of about 5,500 degrees Celsius, which is typical for a star like the Sun. However, the material in its atmosphere reaches a puzzling peak of 2 million degrees Celsius at its highest layer, known as the corona.
A solar storm causes pink auroras in the sky of Tasmania (Australia) – (Photo: NEWS.COM.AU).
Humanity has known about this temperature inversion in the corona since the 1940s, and it is believed to be a common feature in stars. However, scientists have been unable to determine why it is so hot.
One of the leading candidates to explain this phenomenon is the continuous magnetic reconnection at a small scale, according to the website Science Alert.
Most stars are extremely hot plasma spheres, moving chaotically. A fluid made from charged particles interacts strongly with electromagnetic forces. This means that objects like our Sun have extremely complex and chaotic magnetic fields.
Outside the innermost layer of the Sun’s atmosphere, known as the photosphere, these magnetic field lines can twist, extend, separate, and then reconnect. This creates a massive release of energy.
On a smaller scale, scientists believe that these reconnection events will transfer energy into the corona, thereby providing it with a source of heat. However, the Sun is very hot and bright, making it challenging to observe.
What did the solar probe observe? The ESA’s Solar Orbiter spacecraft was launched in February 2020 and has approached the Sun. As the spacecraft neared the Sun for the first time, it observed something remarkable. On March 3, 2022, ultra-high-resolution images in ultraviolet wavelengths showed magnetic reconnection occurring at an extremely small scale on the Sun, with a width of only 390 km. This confirms a long-standing hypothesis and brings scientists one step closer to solving how the corona is heated. The study has been published in the journal Nature Communications. |
