It is not a secret that our Sun is quite an average star in relation to all the others that we observe in the deep and beautiful darkness of space. But nevertheless, it is still a rather calm little nuclear reactor. It produces pseudo-tornadoes and solar flares and sends complex streams of plasma into space.
Incredible news
Carrying out regular observations, scientists made a discovery that adds another remarkable fact to our knowledge.
According to a new article in the Astrophysical Journal, the Sun increases and decreases every eleven years by approximately 1 to 2 km. Figuratively, you can beautifully say that it breathes, albeit very slowly.
This is a very weak "inhale" and "exhale" as these additional kilometers increase the Sun's radius by only 0.00029 percent. With that in mind, it's incredible that a team of researchers from the New Jersey Institute of Technology and the University of the Cote d'Azur were lucky enough to spot it at all. So how did they do it?
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Saxophone and the Sun
As with several recent studies, the team analyzed plasma streams escaping and returning to the sun's surface - high-energy ionized gas filaments.
It turns out that the frequency of oscillations of plasma waves flowing over a star is in many respects similar to the sound waves emitted by a musical instrument.
For example, you have a saxophone because you like jazz. You play on the right note, the noise comes out, and you're good. Now, if the tubing inside the saxophone suddenly expands outward, the tone of that note will drop. Squeeze it all together and the tone will be higher.
In this sense, the Sun is a bit like a magic saxophone. Its wave frequencies change according to how large the sun is. And it can be measured fairly accurately by scientists on Earth. However, the science work was not easy: in the end, it took 21 years of observations with two separate NASA space telescopes.
Cycles of magnetic activity
People who follow solar science among the readers may have already guessed what this "breathing" is connected with. And they will be right: it has to do with the solar cycle.
Every eleven years, the Sun changes from its violent maximum to a calm minimum. At the maximum of the cycle, sunspots - dark spots of intense magnetic activity - appear more often and are grouped just above and below the equator.
More than sunspots, solar storms have a chance to affect the Earth. When they appear, they cause at least brighter sunrises in our skies. As a maximum, they lead to malfunctions in the electrical infrastructure. Sunspots are becoming rather rare.
This influence is driven by magnetic activity hidden deep within the Sun. Indeed, the plasma waves that the team tracked also float below the surface at a depth of several million meters. In terms of distance, it is close to the radius of the Earth.
The sun expands slightly during the minimum and contracts during the maximum. Although the researchers note that there is currently no theory that links these movements to changes in the Sun's internal magnetic fluxes. Scientists speculate that the shape change is due to cyclical fluctuations in magnetic fields.
No reason to panic
The field of research bears an extremely sonorous name: helioseismology, which is essentially the equivalent of terrestrial seismology (like listening to displacement changes or volcanic tremors), but in space.
Just in case you wondered this question, let's clarify: no, this incredibly small change in the shape of the Sun does not affect the climate here on Earth.
We still have to fight anthropogenic climate change. Let's stop doubting in the bud and never talk about it again.
