Sky-watchers and astronomers witnessed a spectacular display of natural lights on Friday caused by the strong solar flare that occurred on Aug. 2, 2011.

The flares, which are backed by a small radiation storm and a spectacular coronal mass ejection (CME), stimulated aurorae on Friday night and could disrupt power grids and satellites.

The Northern Lights lit up the night sky unusually far south on Friday. Auroras were photographed in United States in Montana, Maine, Colorado and even Nebraska, while reports of Northern Lights also came from many European countries including Germany, Denmark, Scotland and the Netherlands.

An aurora is a natural light display in the sky, particularly in the polar regions. It is usually observed at night and typically occurs in the ionosphere. It is also referred to as a polar aurora. It is caused by the collision of charged particles directed by the Earth's magnetic field.

The National Weather Service (NWS) issued a warning for G3 (Strong) Geomagnetic Storm as G2 (Moderate) conditions has already surpassed.

The solar flares caused some radio blackouts Wednesday and Thursday, and caused some disruptions of high-frequency communications with airplanes flying over the Atlantic and Pacific oceans.

A solar flare is caused when intense burst of radiation comes from the release of magnetic energy associated with sunspots. Flares are the solar system's largest explosive events. A CME happens when the outer solar magnetic fields are closed, often above sunspot groups, and the confined solar atmosphere can suddenly and violently release bubbles of gas and magnetic fields.

While a strong solar flare increases the chance of a spectacular light show, the electromagnetic pulse can also disrupt satellite communications, power grids and radio traffic when it passes the Earth. Some industries that are usually affected by solar flares include electrical power grid companies, airlines, GPS, military and ocean shipping routes.

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