What happens when the sun unleashes a massive solar flare?

Flares originate from sunspots—areas on the sun’s surface that have high magnetic activity. These flares and other activities of the sun throw ionised gases or plasma towards the earth. The plasma has an electromagnetic field which, on interaction with the earth’s magnetic field, gives rise to a solar storm.

Being the largest explosion in the solar system, a storm releases as much energy as a thousand billion atom bombs bursting together. It can knock out satellites affecting telecommunication; power grids causing blackouts; and disturb transport and finance systems.

The sun’s magnetic activity goes up and down on a fairly regular 11-year cycle. The highs are full of sunspots, the lows see less or no sunspots. At present, the sun is in the midst of an active phase of a solar cycle. This cycle is called the solar cycle 24 counting since 1755 when recording of solar sunspot activity began. According to scientific data, many solar storms are expected in the near future because the current cycle is reaching its peak. In August 2010, the first storm of the solar cycle 24 occurred. Before this, a storm occurred in December 2006.

The good thing is, these episodes did not cause much destruction. The intensity of a solar storm depends on the direction of the plasma’s electromagnetic field. If it is parallel to the earth’s magnetic field, the charged particles cannot affect it. The bad thing is, a massive solar storm can cause mayhem.

The recent Japan nuclear crisis, for instance, showed how power outages can affect functioning of a nuclear power plant. The storms result in huge monetary losses too. A storm in January 1994 affected Canada’s two telecommunication satellites. The first satellite recovered in a few hours but nearly US $50 million was spent to repair the second one.

Airlines in the US had to alter their high latitude routes because a solar storm in October 2003 had affected high frequency communication in the country. The rerouted flights cost airline firms about US $100,000 per flight. The firms suffered similar losses during the January 2005 storm. A February 14, 2011 solar storm was mild but affected China’s shortwave radiocommunication system.

The loss is expected to be more now since the world is more dependent on satellites and telecommunication. Installation of shields to satellites and transmission lines can prevent damage from solar storms. Better monitoring of flares is also an option as satellites and grids can be shut down before a solar storm to minimise damage. The US federal agency National Oceanic and Atmospheric Administration can predict occurrence of a solar storm one to three days before.