The Solar Orbiter has been observing the sun since 2021, but it recently went on a side trip to Venus which significantly tilted its orbit and gave it a good view of the sun’s polar region. That is how it was able to capture images that will historically be known as humankind’s first-ever views of the sun’s pole. All our galaxy’s planets and the other spacecraft we’ve deployed orbit the sun around an imaginary ecliptic plane along the star’s equator. But thanks to the Solar Orbiter’s Venus flyby, it now has a view of the sun from below its equator, allowing it to see the star’s southern pole clearly. The images you see above were captured from an angle of 15 degrees below the equator on March 16 and 17, but the probe has reached the 17 degree maximum angle it could achieve since then.
Three of the probe’s instruments were responsible for the images. The Polarimetric and Helioseismic Imager (PHI) imaged the sun in visible light and mapped its surface magnetic field. Meanwhile, the Extreme Ultraviolet Imager (EUI) imaged the sun in ultraviolet light, and the Spectral Imaging of the Coronal Environment (SPICE) instrument captured light “coming from different temperatures of charged gas above the sun’s surface, thereby revealing different layers of the sun’s atmosphere.”
So what exactly was the Solar Orbiter able to observe at the sun’s southern pole? Well, the pole’s magnetic field, simply put, is a mess at the moment. See, the sun’s magnetic field flips roughly every 11 years, and it’s about to flip this year if it hasn’t yet. Normally, a magnet has a clear north and south pole, but the orbiter’s PHI instrument showed that both north and south polarity magnetic fields are present at the sun’s south pole right now. “This happens only for a short time during each solar cycle, at solar maximum, when the Sun’s magnetic field flips and is at its most active,” ESA explained.
After the flip, the magnetic field fixes itself so that the poles have single polarities. The process is gradual, however, and it will take five to six years to achieve solar minimum, wherein which the sun’s magnetic field is at its most orderly. These solar cycles or regular magnetic field flips aren’t fully understood yet, and the orbiter’s observations could be the key to unlocking that knowledge.
In addition, scientists used the orbiter’s SPICE instrument to take Doppler measurements, or how fast clumps of solar material are moving. They then took that information to create a velocity map that shows how solar material moves within a specific layer of the sun. These measurements can show how the sun flings out particles into space in the form of solar winds, which is one of the orbiter’s key goals.
