Northern Lights Forecast: Aurora Activity Expected to Increase This Month

Did you miss out on seeing the northern lights earlier this year? You may be in luck—either leading up to or following the fall equinox, which occurs on September 22, unusually intense geomagnetic storms are predicted to occur. These storms may give stargazers increased opportunities to see the aurora borealis this month.

The strong geomagnetic storms are caused by a phenomenon known as the Russell-McPherron Effect. This effect was explained in a paper published in 1973 by Christopher Russell and Robert McPherron. In the paper, the geophysicists share their theory for why the northern lights are so active around March and September—Earth's two equinoxes.

Typically, the magnetic fields of the Earth and solar wind are misaligned. The geophysicists argue that during March and September, the magnetic fields of the Earth and solar wind momentarily line up, which can result in more auroral activity.

The solar wind is created by a collection of charged particles from the sun's outermost atmosphere, the corona. The particles are heated until the sun's gravity can't hold them, then travel along its magnetic field lines. As the sun rotates, it winds up its magnetic field lines into a rotating spiral that creates a wind stream.

When charged particles from the solar wind enter Earth's magnetosphere, they slam into the atmosphere and collide with oxygen and nitrogen particles. When these particles lose the energy they picked up from the collision, each atom starts to glow in a different color, creating what we know as the northern lights.

During the equinoxes, Earth's magnetic poles are tilted and can receive these charged particles more easily. While it's not guaranteed, stargazers will likely see an uptick in northern lights activity throughout September around the fall equinox due to this phenomenon.