A snake seeming to sinuously slink across the surface of the Sun has been captured in a new video by an observatory in close solar orbit.
However, the “serpent” spotted by the European Space Agency’s Solar Orbiter is not a real stellar squamate but a newly observed solar phenomenon that may be linked to massive eruptions from a restless Sun.
The Orbiter observed the moving structure on 5 September as it moved in for its close approach – called a perihelion – planned for 12 October, the closest Solar Orbiter had been yet. (The video from that encounter was just incredible, by the way.)
As Solar Orbiter approached, it imaged a rippling line propagating a long path across the Sun. Solar scientists say this is a cooler tube of plasma in the surrounding hot plasma of the Sun’s atmosphere, bound by solar magnetic fields.
The video shows the plasma snaking across the Sun from one side to the other, following a filament of the solar magnetic field.
“You’re getting plasma flowing from one side to the other, but the magnetic field is really twisted. So you’re getting this change in direction because we’re looking down on a twisted structure,” explains astronomer David Long of University College London in the UK.
Solar magnetic fields are complicated, and attempting to understand them and their behavior is an ongoing Herculean effort.
But the solar atmosphere consists of plasma made up of charged particles that are easily confined by magnetic fields.
This is why fusion generators such as tokamaks rely on magnetic fields for plasma confinement – but it also means that if you can follow the structures in the plasma, you can get a pretty good idea of what the magnetic fields are doing.
The solar snake allows scientists to see the magnetic field moving, but it’s what it’s moving away from that makes it even more intriguing.
Shortly after the filament carved its path across the Sun, its starting point erupted in a coronal mass ejection, sending plasma blasting out into space.
These eruptions are usually associated with sunspots, regions of concentrated magnetic field lines on the Sun. These magnetic field lines tangle, snap, and reconnect, producing coronal mass ejections and sometimes solar flares.
It’s possible the snake was somehow connected to one of the most powerful detected by Solar Orbiter since it was launched in February 2020, perhaps as a precursor to the eruption.
Solar Orbiter isn’t alone up there, either; NASA’s Parker Solar Probe was directly in the line of fire of the coronal mass ejection. It’s unharmed – it was designed to withstand solar tantrums, and measure them to boot, so we’re all eagerly waiting to see what it found in the plasma ejected by such a monumental eruption.
Meanwhile, the next Solar Orbiter perihelion is due to take place in April of next year. The Sun’s sunspot activity continues to increase, leading into the peak of its 11-year activity cycle, so we’re excited to see what the little probe shows us next.