Imagine a huge fiery ball that seems familiar and almost calm to us. In reality, the Sun is a giant cauldron where invisible magnetic forces govern everything: from graceful plasma loops to powerful flares that can affect satellites and power grids on Earth. And these forces have long remained one of the biggest mysteries of solar physics. It is especially difficult to measure the magnetic field in the corona—the star's outer atmosphere, where temperatures reach millions of degrees.
Scientists from the U.S. National Solar Observatory have found an elegant way to 'hear' this field. Astrophysicist Alin Paraschiv developed a technique that combines two seemingly different approaches. The first is observing polarized light emanating from the corona. The second is analyzing waves that travel through the solar atmosphere, much like seismic vibrations inside our planet. Together, they allow reconstructing both the strength and direction of the magnetic field with accuracy comparable to much more complex and expensive methods.
'The Sun looks like a bright fluffy ball, but its magnetic field is a hidden force that shapes all its beautiful features and drives space weather,' says Paraschiv. 'We are learning to take a kind of magnetic snapshot without approaching the star.'
The essence is that polarized light and waves carry information that was previously considered lost. The scientist created an open software tool that allows extracting this data. The method works especially well with modern telescopes, such as the four-meter Daniel K. Inouye Solar Telescope in Hawaii. Now measurements of the coronal magnetic field can become more regular and accessible.
This is not just technical progress. Magnetic fields in the corona trigger solar eruptions that travel across the entire solar system. The more accurately we see them, the better we understand when and how strong the next 'space storm' might be. And that means we can better protect technology and people working in space.
Behind this work lies something more than just another scientific instrument. We stand before a star that has been shining for billions of years, and we are gradually learning to read its secret language. Waves, light, magnetic lines—all of this forms a complex yet surprisingly coherent picture. Just as seismic waves inside the Earth reveal the planet's structure, solar oscillations allow us to peer into the very heart of our Sun. And the deeper we look, the clearer it becomes: we live in a world where even the invisible is arranged with remarkable precision and beauty.
