By Scott Hamilton

Last week I received a question about a post floating around on the internet about a coming geomagnetic storm. In the article there were several statements being made to cause a lot of fear over something that is a very normal occurrence. There are certain times of the year when these storms are strong enough to cause major interference with television, satellite and radio signals, but most of the time we do not even know a geomagnetic storm has occurred.

What causes the geomagnetic storms is when there is a very efficient transfer of energy from the solar winds into the space around Earth. These storms are a result of variations in the solar wind that produce major changes in the electromagnetic field of the Sun. The Earth and Sun have electromagnetic fields that overlap one another and are usually fairly balanced and cause little interference with one another, but occasionally the solar field shifts during a southern solar wind and causes the magnetic field of the Earth to drop significantly.

If you want to see the effects of the geomagnetic storms, you can actually watch them by installing a magnetometer application on your cell phone. This is an application that uses the magnetometer in our cellphone, which is there to provide input for the compass and navigation applications on your phone. The application takes periodic readings from the magnetometer and reports the strength of any magnetic fields around the phone. You can see the current magnetic force levels around your phone and watch for changes while the device is stationary. Any of these stationary changes can be either from a geomagnetic storm or from another nearby device creating a magnetic field, so don’t get too excited over spikes and dips in the magnetic force; it is much more likely from another device.

NASA and NOAA both have a prediction center on their website that attempts to predict the arrival of the storm based on data collected from the sun. The sun releases plasma in very large amounts, billions of tons, during coronal mass ejections (CMEs), which are a necessary part of the chemical reactions within the sun. These large plasma releases also release massive amounts of electromagnetic energy. It usually takes several days for the field to reach the earth after these CMEs are observed, so we usually know when to expect the surge. However, sometimes they can arrive in as little as 18 hours.

During storms, the electrical currents in the ionosphere increase the temperature of the upper atmosphere. The increase in temperature increases the drag on low earth orbit satellites, which cause positioning issues that interfere with satellite TV, GPS systems and satellite internet services. The localized heating in the ionosphere also causes the paths of radio signals to bend in strange ways, creating interference and increasing the error rate of the positioning information provided by GPS systems.

If you are lucky enough to be far north or south nearer to poles, you will see an increase in the color and size of the aurora, but do not expect stability from your electronics during such a storm. They can cause power outages by inducing extra power into the power grid and disrupt electronic signals of all kinds. The good news is they rarely cause any permanent damage to these systems and they only last a few minutes, in bursts spread over several days.

Ultimately geomagnetic storms are nothing to be concerned about and if you hear about one, take some time to go out and look to the northern sky. On rare occasions these storms are strong enough to let us see the aurora in Missouri. Until next week, stay safe and learn something new.

Scott Hamilton is a Senior Expert in Emerging Technologies at ATOS and can be reached with questions and comments via email to

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