Dark side of the Northern Lights

Sir, – Spectacular as the Northern Lights seen in Donegal on Monday night may have been (Front page Home News, January 24th), …

Sir, – Spectacular as the Northern Lights seen in Donegal on Monday night may have been (Front page Home News, January 24th), the solar storms that produced these auroral displays can have more sinister effects. During periods of increased solar activity, storms can cause errors in GPS positions, disrupt radio communications, cause instabilities in electrical power systems, and damage electronics on satellites.

These effects are nothing new. Following the great solar storm of September 1st, 1859, daily London stock market prices were not received in Dublin due to a "mysterious atmospheric phenomena" ( The Irish Times, September 3rd, 1859), while telegraph operators in Valentia reported receiving electrical shocks in the course of operating the transatlantic cable between Co Kerry and Newfoundland in the late 1800s.

Of more concern was the March 1989 solar storm, which disrupted electric power transmission from the Hydro Québec generating station in Canada, plunging six million people into darkness for nine hours and burning out a power transformer at a nuclear power plant in New Jersey (which is at a lower latitude than Ireland); while very recently, a portion of the GPS network, including a GPS receiver in Shannon, was interrupted for approximately eight minutes following a solar storm in September 2011.

With solar activity expected to reach very active levels in 2012 and 2013, we can expect further spectacular aurora displays and and very possibly interruptions in the technologies on which we depend as part of our everyday lives. Luckily for us though, large geo-effective solar storms and their adverse effects are rare. – Yours, etc,

Dr PETER T GALLAGHER,

School of Physics,

Trinity College Dublin.