Scottish sky watchers must have had a wonderful surprise when the "northern lights" lit up the sky on Tuesday, said experts in a BBC report. Scientists at the UK-based AuroraWatch spotted the lights in the skies over Durness, Highland on Tuesday. The phenomenon is expected to light up the skies on Wednesday too.

Also known as the "Aurora Borealis", this unique spectacle is caused by the collision of charged particles directed by the Earth's magnetic field. When this energy is released from the magnetic mechanism into the atmosphere, it becomes visible to the human eye as it glows in different colorful forms. However, this sudden burst of radiation and magnetic energy can also disrupt communications equipment.

The spectacular "Aurora Borealis", mainly visible in the Arctic, can be seen clearly across the UK every decade.

According to a thematic color scheme, a red alert explains the likelihood of an aurora visibility across the UK; an amber alert explains its presence from Scotland, northern England and Northern Ireland. Yellow, however, signifies minor geomagnetic activity and is very rarely to be seen, except maybe in the extreme north of Scotland. Green does not reveal any significant activity and is hard to be seen in the UK.

"The main effect has now passed but if there is a dark sky go outside and have a look north. You might be able to see an after wash from last night. People can log on to AuroraWatch UK and register for sighting alerts," said Jim Wild, a space scientist at AuroraWatch, in the BBC report.

Check out spectacular "Auroras Borealis" sightings from around the world.