(ORDO NEWS) — A new type of high-frequency acoustic wave propagating into the Sun has baffled scientists.
Waves appear on the surface of the Sun in the form of swirling vortices moving against the rotation of the star.
The problem is that these high-frequency retrograde vortices travel three times faster than theory predicts, and solar physicists have been unable to determine why.
The discovery, they say, suggests we have yet to uncover new solar physics, and also provides new insights into the Sun’s internal properties and activity.
What is hiding inside the sun
While we can’t actually look inside the Sun, stars are remarkable in that their internal processes can often be inferred from surface activity.
In particular, acoustic waves can tell us a lot. They are generated close to the surface and then partially or completely reflected inward, where they resonate, creating acoustic vibrations. Solar scientists study these oscillations to learn about the interior of the Sun.
A team of scientists led by solar physicist Chris Hanson of New York University Abu Dhabi studied and analyzed such data using 24 years of observations from the ground-based Global Oscillation Network Group and 10 years of observations from space-based Helioseismic, as well as magnetic imager scanner.
In the data, the researchers found a very consistent signal the presence of previously unseen waves. They formed a pattern of vortices on the surface of the Sun with antisymmetry between the north and south poles moving against the rotation of the star.
However, the fact that these waves are moving three times faster than expected is a mystery. The team explored a number of possibilities as to why this is happening.
First, the Coriolis force – the way a spinning spherical object’s equator moves faster than its poles – excites the swirling waves we know can occur here on Earth.
In addition, there are three mechanisms that can influence and change waves: magnetism, gravity, or convection. However, none of them could explain the observational data.
“If high-frequency retrograde waves could be attributed to any of these three processes, then the discovery would answer some of the open questions we still have about the Sun,” says Hanson.
“However, these new waves do not seem to be the result of these processes, and this is interesting because it leads to a whole new set of questions.”
The researchers say this suggests that our models of the Sun are missing or poorly limited information that could make up for unraveling the mystery.
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