A spacecraft just got the first look at the bottom of the sun, and what it saw was a hot mess — literally.
Our host star, about 93 million miles away in space, is in utter turmoil right now, having just reached peak chaos in its solar cycle. Similar to storm seasons on Earth, the sun experiences a weather pattern that repeats every 11 years. At the beginning and end of this stretch, flares and sunspots calm down. But solar activity rises before it falls, and when it climaxes, the sun roils with giant eruptions.
The Solar Orbiter, a collaborative mission between the European Space Agency and NASA, captured detailed images of the sun’s southern region in March, something no other probe has done at close range. While previous spacecraft have taken pictures around the sun's middle, the Solar Orbiter tilted to get the unprecedented southern view.
What its instruments observed wasn't unexpected, though it remains mysterious: The poles had flipped. While a normal magnet has clear north and south poles, both of the sun's poles occupy the bottom now. This happens only for a short period during "solar maximum" before a single polarity eventually takes over, and the entire magnetic field reorders itself in the reversed configuration.
"How exactly this build-up occurs is still not fully understood," said Sami Solanki, leader of one of the orbiter instrument teams from the Max Planck Institute for Solar System Research, in a statement, "so Solar Orbiter has reached high latitudes at just the right time to follow the whole process from its unique and advantageous perspective."
The spacecraft, launched in 2020, used a gravity assist from Venus in February to swing out of the sun’s equatorial plane. That change in trajectory gave its cameras the fresh angle to see the southern region. One previous spacecraft — NASA and ESA's now-defunct Ulysses mission that began in the 1990s — flew over the sun's poles but did not have the ability to take pictures.
The orbiter comes equipped with several instruments that have different purposes. One images the sun in optical light, and another captures ultraviolet light. Two others map the sun's surface magnetic field and capture light from different temperatures of charged gas above the sun's surface.
Though the basis of the solar cycle — our star's internal clock — remains unclear, scientists think the key to understanding it lies at the poles. One of the primary mission objectives for the orbiter is to try to figure it out. Its findings may also improve predictions for space weather events that can disrupt power grids, satellites, and navigation systems.
In the March images, the orbiter viewed the sun from an angle of 17 degrees below the solar equator. Over the coming years, the spacecraft will tilt even farther. In December 2026, the orbit will change to a steeper 23 degrees. By 2029, it may reach 33 degrees to fully map both poles.
Topics NASA
