The primordial magnetic field in our cosmic backyard
At the very beginning of the Universe, not only elementary particles and radiation were generated but also magnetic fields. A team of researchers led by the Max Planck Institute for Astrophysics now calculated what these magnetic fields should look like today in the local universe – in great detail and in 3D. To achieve this, first they traced back the current distribution of matter to the time of the Big Bang; this distribution of matter was then used to calculate the generation of the magnetic field; and finally the resulting fields were translated back to the present. Thus, the researchers were able to predict the structure and morphology of the primordial magnetic field in our cosmic neighbourhood for the first time. This field is incredibly weak; nevertheless, the prediction could help to address the challenge of measuring it.
Fig. 1: Sky view of the Harrison magnetic field strength averaged within a sphere with 300 million light years radius around the Earth. The region with stronger fields on the left side of the image is the Perseus Pisces galaxy cluster, the one in the upper part is the Virgo cluster.