Jupiter & Sunspots
20 March 2004
New Scientist Letters
Glyn Wainwright Leeds, UK
While the work of Mausumi Dikpati suggests that
meridional flows in the sun's convective layer may allow us to forecast
sunspot activity (6 March, p 38), other forces may also be at work. In
particular, the giant planets in the solar system may play a role through the
gravitational pull they exert on the massive amount of fluid flowing in the
outer layer of the sun.
Curiously, this gravitational force can be expressed as
a Fourier series whose most important terms have interesting periodicities:
one of these coincides with the 11-year cycle of the sunspots. What we may be
seeing, therefore, is the direct influence of planetary tidal forces and
their effects on the stability of the magnetic loops created in the
meridional flows in the sun's convective layer. These forces could be a major
factor in the cycle of magnetic loops believed to create the sunspots.
Jupiter is the largest contributor to the solar plasma
tides. It may eventually transpire that its influence contributes to our
From issue 2439 of New Scientist
magazine, 20 March 2004, page 32.
on Solar Tides &
Link to Sunspot & Jovian Tide Data