Indeed, there are many strange things about the sun, but a well-known space probe has given us a clue that we may have to solve one of them.
New observations from the European Space Agency’s (ESA) Solar Orbiter show that the constant reconnection of tiny magnetic field lines may be at least part of why some parts of the sun are hotter than others. .
The problem is, the sun’s surface is about 5,500 degrees Celsius (9,932 degrees Fahrenheit) — a normal temperature for a sun-like star. But the material in its atmosphere heats up even further from the surface, reaching 2 million degrees Celsius in the uppermost region known as the corona.
We have known about this coronal temperature reversal since the 1940s, and it is considered a common feature of stars. But what scientists cannot determine is the cause. A candidate solution is permanent magnetic reconnection on a small scale.
At least on a large scale, magnetic reconnection is a well-documented solar behavior. Most stars are chaotic balls of incredibly hot plasma. A fluid composed of charged particles interacts strongly with electromagnetic forces. This means that objects like our sun positively vibrate in a highly complex and chaotic magnetic field. And outside the innermost layer of the sun’s atmosphere known as the photosphere, these magnetic fields can intertwine, stretch, capture and reconnect.
It produces massive bursts of energy – the engine that powers solar flares and coronal mass ejections that send explosive particles throughout the solar system.
On smaller scales, scientists believe that these reconnection events will inject energy into the corona, thereby providing a source of heating. However, the sun was so bright and hot that it was difficult to observe it; We don’t have enough resolution to see the small scales where this process takes place.
This is where the Solar Orbiter comes in. Launched in February 2020, the European Space Agency’s (ESA) solar probe is approaching our star, zooming in dangerously close-ups in a series of repeated encounters to study the activity of our star in stunning detail.
When the spacecraft first approached, he noticed something surprising. On March 3, 2022, ultra-high resolution images at extreme ultraviolet wavelengths showed magnetic reconnection occurring on extremely thin scales, just 390 kilometers (242 miles) across.
It’s really incredible. Scientists have been able to unravel and study a phenomenon that is slightly smaller than the length of the “Grand Canyon” on the surface of the sun.
Within an hour, the spacecraft recorded a point known as the null point, where the strength of the magnetic field drops to zero. This is the magnetic reconnection point. During this time, the zero point temperature is maintained at approximately 10 million degrees Celsius. The blank area also produced a continuous jet, visible as “drops” of plasma, flowing at about 80 kilometers per second.
This is known as “soft” reconnection, but the null point also showed a more vigorous phase of reconnection. The reconnection process took just four minutes, but showed that the two types of reconnection are happening simultaneously and at much smaller scales than we could resolve before.
These two types of reconnection transfer mass and energy to the corona above them, providing a source of heat that may explain at least some of the poorly understood temperature reversals.
The results also show that reconnection can occur on scales too small for the Solar Orbiter to resolve, at least at this close approach. In addition to the one on April 10, the next few images will be zoomed in, which may lead to higher resolution observations.
Meanwhile, we have the first observational evidence of robust, small-scale magnetic reconnection occurring on the Sun’s surface, confirming a long-standing hypothesis about how the corona is heated and bringing us one step closer to understanding how the corona is heated. corona.
The research was published in the journal Nature Communications.
Source: ScienceAlert
Source: Arabic RT
