Sun could jeopardise electrical systems

A fresh bout of heightened solar activity has officially begun, bringing with it increased risks for power grids, critical military, civilian and airline communications, GPS signals and even cell phones and ATM transactions.

The cycle's first sunspot appeared in the sun's Northern Hemisphere on 3 January, NOAA scientists said.

"This sunspot is like the first robin of spring," said solar physicist Douglas Biesecker from the US National Oceanic and Atmospheric Administration's (NOAA) Space Weather Prediction Center.

"In this case, it's an early omen of solar storms that will gradually increase over the next few years."

A sunspot is an area of highly organised magnetic activity on the surface of the sun. They vary in number "” going from a minimum to a maximum and back to a minimum again "” about every 11 years, the same timescale on which the sun's magnetic poles reverse direction.

The new 11-year cycle is expected to build gradually with the number of sunspots and solar storms reaching a maximum by 2011 or 2012, though devastating storms can occur at any time.

During a solar storm, highly charged material ejected from the sun may head towards Earth, where it can bring down power grids and disrupt critical communications. The storms can knock out commercial communications satellites and swamp GPS signals. Routine activities such as talking on a cell phone or getting money from an ATM machine could suddenly halt over a large part of the globe.

"Our growing dependence on highly sophisticated, space-based technologies means we are far more vulnerable to space weather today than in the past," said Vice Admiral Conrad Lautenbacher, Jr, under secretary of commerce for oceans and atmosphere and NOAA administrator.