In a first since the Halloween storms of October 2003, which caused blackouts in Sweden and destroyed power infrastructure in South Africa, the most powerful solar storm in over two decades struck Earth on Friday.

From Tasmania to the United States, the rare solar event has triggered a display of spectacular celestial auroras in skies across nations. However, besides the magnificence and surprise, the hyperactive solar event also holds the potential to cause threatening disruptions to satellites and power grids as it is expected to persist till the weekend.

About the 'extreme geomagnetic solar storm'

The source of the storm is a massive sunspot cluster that is 17 times wider than the Earth. Sun approaching the peak of an 11-year cycle has been cited as the primary reason behind the intense solar activity.

Anticipating the occurrence of the celestial event, the US National Oceanic and Atmospheric Administration (NOAA), issued a rare solar storm warning. On Friday, NOAA said that the solar outburst reached Earth at about 16:00 GMT, hours sooner than anticipated.

Soon after hitting the Earth, the storm was upgraded to an 'extreme geomagnetic storm', the first since the so-called 'Halloween Storms' of October 2003.

According to NOAA, the solar storm resulted from the ‘first of several coronal mass ejections (CMEs), which are defined as expulsions of plasma and magnetic fields from the Sun. The space watchdog further added that several other coronal mass ejections (CMEs) are expected to hit Earth in the coming days.

Social media lit up with Northern Lights visible across countries

Owing to the heightened solar activity, spectacular auroras were spotted across countries in Europe, Australasia, Britain and the United States. Social media has been inundated with breathtaking views of the rare celestial extravaganza which, in general, stays confined within the limits of the polar regions.

Solar storm likely to affect power grids, communications

Taking cognisance of te possible disruptions caused by the Earth's magnetic field, authorities across countries have notified satellite operators, airlines and the power grid to stay alert and take precautionary steps. Fluctuations in magnetic fields caused by the strong geomagnetic storms often induce currents in long wires, including power lines, which can potentially lead to blackouts. Mreover, long pipelines are also very likely to become electrified, leading to engineering problems.

Unlike solar flares, which travel at the speed of light and reach Earth in around eight minutes, CMEs travel at a more sedate pace, with officials putting the current average at 800 kilometers (500 miles) per second.