Other effects, such as light scattering from cosmic dust and the synchrotron radiation generated by electrons moving
around galactic magnetic fields within our own galaxy, can also produce these polarisation twists.
We propose that the cycle may be caused by modulation of cosmic ray (CR) flux by the Solar system vertical oscillation (64 My period) in the galaxy, the galactic north - south anisotropy of CR production in the galactic halo / wind / termination shock (due to the galactic motion toward the Virgo cluster), and the shielding
by galactic magnetic fields.
But because the particles are electrically charged, they interact
with galactic magnetic fields, causing them to wander in their journey to Earth.
About three years ago they and another research team working independently at Princeton found a serious flaw in what has been the most widely accepted theory
of galactic magnetic fields — a theory that with slight variations has also been used to explain the magnetic fields of individual stars such as the sun.
Since this galaxy is seen as it was almost five billion years ago, when the universe was about two - thirds of its current age, this discovery provides an important clue about
how galactic magnetic fields are formed and evolve over time.
It is likely that the polarization arises because the dust grains are partially aligned by
the galactic magnetic field.