Strange processes occur on the Sun: a new discovery has puzzled scientists

The Sun, the star that warms our planet, is a constant source of mystery for scientists. One of them is why some parts of the sun are much hotter than others and what causes this heating.

The Science Alert publication has reported that scientists have finally come close to solving it. The European Space Agency's Solar Orbiter spacecraft, which approached the star to an unprecedented distance, was able to see the processes in the star's magnetic field. To watch the video, scroll down to the end of the news story.

Scientists knew that the surface of the Sun has a temperature of about 5,500 degrees Celsius, but as it goes deeper into its atmosphere, it rises to 2 million degrees. The surface temperature is typical for a sun-like star, but what happens deeper down confused the researchers. They could not determine what caused the coronal temperature inversion.

However, the dominant assumption was the theory of a permanent small-scale magnetic reconnection of the magnetic field lines of the Sun. On a large scale, this phenomenon has been observed and well documented.

Most stars are seething turbulent balls of hot plasma. They are a large accumulation of charged particles that interact well with electromagnetic forces. Therefore, objects such as the Sun literally abound with extremely complex and disorderly magnetic fields.

Researchers have found that outside the Sun's inner atmosphere, known as its photosphere, these magnetic field lines can become tangled, stretched, broken, and then reconnected. These processes generate huge releases of energy, which is why solar flares occur and why coronal mass is periodically ejected into outer space.

But this theory has not been confirmed. The Sun is a very hot object, and it was impossible to approach it at a distance that would allow us to observe the reconnection of the power lines.

But the Solar Orbiter, launched in February 2020, was still able to cope with this task. It made several approaches to the Sun and during the first of them recorded something previously unseen. During the approach on 3 March 2022, the probe obtained ultra-high-resolution images in extreme ultraviolet wavelengths. It demonstrated that magnetic reconnection occurs on an absolutely tiny scale, as compared to the Sun, only 390 kilometres across.

Solar Orbiter found a point in the magnetic field where its strength drops to zero - the so-called zero point. This is the point of magnetic reconnection. It observed it for an hour. During this time, the temperature of the zero point was maintained at about 10 million degrees Celsius. The zero point also created a continuous flow of plasma travelling at a speed of about 80 kilometres per second.

This phenomenon is known as a "soft" reconnection, but the zero point also exhibited a phase of sharper reconnection. This explosive reconnection lasted only about four minutes, but it showed that the two types of reconnection occur simultaneously and on a smaller scale than scientists could previously determine.

These two types of reconnection transfer mass and energy to the corona above them. Thus, they provide a heat source that could explain at least some of the poorly understood temperature inversions. The data may also indicate that reconnection can occur on an even smaller scale.

The first evidence that a permanent small-scale magnetic reconnection is taking place on the Sun has finally confirmed the long-standing hypothesis. It also brought scientists closer to unravelling how the solar corona heats up.

Earlier, OBOZREVATEL told you what an unexpected forecast for the peak of solar activity was made by scientists - it could cause certain problems on Earth.

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