The first-ever images of the sun’s south pole reveal a messy jumble of magnetic activity in a never-before-seen region of our nearest star.
The images, taken by the Solar Orbiter spacecraft and released Wednesday by the European Space Agency, offer fresh insights into the sun’s behavior, its magnetic field and how it produces space weather.
“The sun is our nearest star, giver of life and potential disruptor of modern space and ground power systems, so it is imperative that we understand how it works and learn to predict its behaviour,” Carole Mundell, director of science at the European Space Agency (ESA), said in a statement. “These new unique views from our Solar Orbiter mission are the beginning of a new era of solar science.”
The images have already been a boon for heliophysicists, showing turbulent magnetic activity at the south pole as the sun ramps up to the most active phase of its natural cycle.
The solar cycle typically spans about 11 years, with the sun going from a quiet period of low magnetic activity to a highly active phase characterized by intense solar flares and solar storms. As the sun reaches peak activity — a phase known as the solar maximum — its magnetic poles flip, meaning the sun’s south pole becomes magnetic north.
Why exactly that happens is unclear, as are precise forecasts for when it will occur. Solar Orbiter may be able to tease out some of these answers.
From the spacecraft’s observations, scientists discovered that magnetic fields with both north and south polarity are currently present at the sun’s south pole. This mishmash of magnetism is expected to last only a short time during the solar maximum before the magnetic field flips.
Once that happens, a single polarity should slowly build up over time at the poles as the sun heads toward its quiet solar minimum phase, according to ESA.
“How exactly this build-up occurs is still not fully understood, so Solar Orbiter has reached high latitudes at just the right time to follow the whole process from its unique and advantageous perspective,” said Sami Solanki, director of the Max Planck Institute for Solar System Research in Germany and lead scientist for Solar Orbiter’s PHI instrument, which is mapping the sun’s surface magnetic field.
Scientists have enjoyed close-up images of the sun before, but before now, they have all been captured from around the sun’s equator by spacecraft and observatories orbiting along a plane similar to Earth’s path around the sun.
But Solar Orbiter’s journey through the cosmos included close flybys of Venus that helped tilt the spacecraft’s orbit, allowing it to see higher-than-normal latitudes on the sun.
The newly released images were taken in late March, when Solar Orbiter was 15 degrees below the sun’s equator, and then a few days later when it was 17 degrees below the equator — a high-enough angle for the probe to directly see the sun’s south pole.
“We didn’t know what exactly to expect from these first observations — the sun’s poles are literally terra incognita,” Solanki said in a statement.
Solar Orbiter was launched in February 2020. The European-led mission is being operated jointly with NASA.
In the coming years, Solar Orbiter’s path is expected to tilt even further, bringing even more of the sun’s south pole into direct view. As such, the best views may be yet to come, according to ESA.
“These data will transform our understanding of the sun’s magnetic field, the solar wind, and solar activity,” said Daniel Müller, ESA’s Solar Orbiter project scientist.
