Washington: In a rare circumstance, stargazers were left mesmerised after a strong geomagnetic solar storm hit the Earth, producing northern lights in the US and other countries. The National Oceanic and Atmospheric Administration (NOAA) issued a rare severe geomagnetic storm warning after a solar outburst reached Earth much earlier than expected, which can produce such strong lights and disrupt power and communications.
NOAA alerted operators of power plants and spacecraft in orbit to take precautions, as well as the Federal Emergency Management Agency. The effects were due to last through the weekend and possibly into next week. The rare warning was issued after the sun produced strong solar flares since Wednesday, resulting in at least seven outbursts of plasma.
The storm could produce northern lights as far south in the US as Alabama and Northern California, according to NOAA. However, it was hard to predict and experts stressed it would not be the dramatic curtains of colour normally associated with the northern lights, but more like splashes of greenish hues.
Watch the video of the northern lights
The unusually strong storm produced spectacular celestial light shows from Britain to Australia. The storm was a result of coronal mass ejections (CMEs), which are explosions of plasma and magnetic fields from the sun’s corona. These explosions cause geomagnetic storms when they are directed towards the Earth. However, geomagnetic storms are not considered dangerous to human bodies.
The most intense solar storm in recorded history, in 1859, prompted auroras in Central America and possibly even Hawaii. “We are not anticipating that” but it could come close, said NOAA space weather forecaster Shawn Dahl. The 'aurora' is known as a natural lights display that is caused by disturbances in the Earth's magnetosphere and appears as curtains, rays and spirals.
What are the risks of these storms?
The National Weather Space Weather Prediction Centre (SWPC) has issued a 'severe geomagnetic storm watch' for this weekend starting from Friday, which is the first time such watch has been issued in nearly 20 years. Several strong flares have been observed over the past few days by scientists and were associated with a large and magnetically complex sunspot cluster, 16 times the diameter of the Earth.
This storm poses a risk for high-voltage transmission lines for power grids, not the electrical lines ordinarily found in people’s homes, Dahl told reporters. Satellites also could be affected, which in turn could disrupt navigation and communication services here on Earth. According to NOAA, they can also cause some protective systems to "trip out key assets from the grid," as well as orientation issues for spacecraft.
An extreme geomagnetic storm in 2003, for example, took out power in Sweden and damaged power transformers in South Africa. Even when the storm is over, signals between GPS satellites and ground receivers could be scrambled or lost, according to NOAA.
NASA said the storm posed no serious threat to the seven astronauts aboard the International Space Station. The biggest concern is the increased radiation levels, and the crew could move to a better-shielded part of the station if necessary, according to SW{C scientist Rob Steenburgh.
(with AP inputs)
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