The same kind of large-scale planetary waves that meander through the atmosphere high above Earth's surface may also exist on the Sun, new research has found.
Just as the large-scale waves that form on Earth, known as Rossby waves, influence local weather patterns, the waves discovered on the Sun may be intimately tied to solar activity, including the formation of sunspots, active regions, and the eruption of solar flares.
"The discovery of magnetised Rossby waves on the Sun offers the tantalising possibility that we can predict space weather much further in advance," said study lead author Scott McIntosh, scientist at US National Center for Atmospheric Research.
On Earth, Rossby waves are associated with the path of the jet stream and the formation of low- and high-pressure systems, which in turn influence weather events.
Unlike Earth, which is scrutinised at numerous angles by satellites in space, scientists historically have been able to study the Sun from only one viewpoint: as seen from the direction of Earth.
But for a brief period, from 2011 to 2014, scientists had the unprecedented opportunity to see the Sun's entire atmosphere at once.
During that time, observations from NASA's Solar Dynamics Observatory (SDO), which sits between the Sun and the Earth, were supplemented by measurements from NASA's Solar TErrestrial RElations Observatory (STEREO) mission, which included two spacecraft orbiting the Sun.
Collectively, the observatories provided a 360-degree view of the Sun until contact was lost with one of the STEREO spacecraft in 2014.
McIntosh and his co-authors of the study, published in the journal Nature Astronomy, mined the data collected during the window of full solar coverage to see if the large-scale wave patterns might emerge.
What emerged from the analysis were bands of magnetised activity that propagate slowly across the Sun — just like the Rossby waves found on Earth, the researchers said.