Why Do the Northern and Southern Lights Differ?

When the magnetic field lines curve symmetrically around Earth, aurorae should appear in identical places in the Northern and Southern hemispheres. It alters the path traced by Earth’s field lines, squashing the lines on our planet’s dayside facing the sun and elongating the lines on the nightside, creating a magnetic tail. His team’s modeling and observations show uneven squeezing in the Northern and Southern hemispheres skews Earth’s field lines and relocates the aurorae.

Source: www.scientificamerican.com