A paper recently published in the Astrophysical Journal goes over how the Sun seems to be growing and shrinking every 11 years by 1-2 kilometers. While this is a very faint change it is something that has been noted for quite some time.
It is as if the sun is doing a very faint inhale/exhale.
The abstract of the study mentioned above goes as follows:
The questions whether the Sun shrinks with the solar activity and what causes this have been a subject of debate.
Helioseismology provides means to measure with high precision the radial displacement of subsurface layers, co-called
‘seismic radius’, through analysis of oscillation frequencies of surface gravity (f) modes. Here, we present
results of a new analysis of twenty-one years of helioseismology data from two space missions, Solar and Heliospheric
Observatory (SOHO) and Solar Dynamics Observatory (SDO), which allow us to resolve previous uncertainties and
compare variations of the seismic radius in two solar cycles. After removing the f-mode frequency changes associated
with the surface activity we find that the mean seismic radius is reduced by 1-2 km during the solar maxima and
that most significant variations of the solar radius occur beneath the visible surface of the Sun at the depth of about
5±2 Mm, where the radius is reduced by 5-8 km. These variations can be interpreted as changes in the solar subsurface
structure caused by predominately vertical ∼ 10 kG magnetic field
The sun seems to expand during the minimum and contract during the maximum. During this, the number of sunspots continue to rise and fall unexpectedly. This study suggests some kind of change in the orientation of the magnetic fields located in the sun.
That all being said, we do not know exactly why this happens or what it could mean in the years to come. Measuring the sun’s shape has proven to be quite the task. Most measurements don’t actually agree with one another at all.
The frequencies of the sun’s waves are always changing depending on the size of the sun. This is something we can measure but not truly understand just yet. More research needs to be done in regards for sure. What do you think about all of this?