AFTER 10 years of comparative slumber, the sun is waking up - and it's got astronomers on full alert. This week several US media outlets reported that NASA was warning the massive flare that caused spectacular light shows on Earth earlier this month was just a precursor to a massive solar storm building that had the potential to wipe out the entire planet's power grid.

NASA has since rebutted those reports, saying it could come "100 years away or just 100 days", but an Australian astronomer says the space community is betting on the sooner scenario rather than the latter.

Despite its rebuttal, NASA's been watching out for this storm since 2006 and reports from the US this week claim the storms could hit on that most Hollywood of disaster dates - 2012. Similar storms back in 1859 and 1921 caused worldwide chaos, wiping out telegraph wires on a massive scale. The 2012 storm has the potential to be even more disruptive.

"The general consensus among general astronomers (and certainly solar astronomers) is that this coming Solar maximum (2012 but possibly later into 2013) will be the most violent in 100 years," astronomy lecturer and columnist Dave Reneke said.

Dr Richard Fisher, director of NASA's Heliophysics division, told Mr Reneke the super storm would hit like "a bolt of lightning", causing catastrophic consequences for the world's health, emergency services and national security unless precautions are taken. NASA said that a recent report by the National Academy of Sciences found that if a similar storm occurred today, it could cause "$1 to 2 trillion in damages to society's high-tech infrastructure and require four to 10 years for complete recovery".

Staff at the Space Weather Prediction Center in Colorado, which hosted the exercise, said with our reliance on satellite technology, such an event could hit the Earth with the magnitude of a global hurricane or earthquake.