Every 11 years, the Sun moves from a violent solar maximum to a tranquil-ish solar minimum. At a maximum, sunspots – dark patches of intense magnetic activity – appear more frequently and cluster just above and below the equator.
More sunspots up the chances of solar storms appearing, which could mean anything from more potent aurorae in our skies to malfunctioning electrical infrastructure. At a minimum, sunspots become more of a rarity.
This activity is driven by the magnetic activity buried deep within the Sun. Indeed, the plasma waves that the team were tracking swim beneath the surface too on the order of several million meters, near to the radius of Earth in terms of distance.
The Sun expands a little during the minimum, and contracts during the maximum. Although the team note that there is currently “no theory” that links the displacements to changes in the internal magnetic machinations of the Sun, they suggest that it’s linked to the change in the orientation of the magnetic fields that occur over the cycle.
The field of research is known by an extremely cool name, by the way: helioseismology, which is essentially the equivalent of terrestrial seismology – like listening to faults move or volcanic tremors – but in space.
Just in case you were wondering: no, this incredibly small change in solar dimensions does not affect the climate here on Earth. We still have to deal with anthropogenic climate change. Let’s nip that one in the bud right there, and never speak of it again.