Stargazers in Scotland have spotted a mysterious new celestial phenomenon -- which has been given the unlikely name 'Steve'.

Sightings of the glowing green and purple lights have been seen during displays of the Aurora Borealis overnight from the isles of Skye and Lewis.

There have also been reported sightings from near Oban in Argyll and Gairloch in Wester Ross.

Given its more accurate description of Strong Thermal Emission Velocity Enhancement, the unusual lights have already sparked the interest of scientists, photographers and astronauts, with Nasa funding a citizen science project to learn more about the optical phenomenon.

It describes Steve as a thin purple ribbon of light, aligned east to west, which can extend for hundreds or thousands of miles.

Lasting for up to an hour, it is sometimes accompanied by "a rapidly evolving green picket fence-like" aurora.

First spied around 2015, Steve has only been spotted so far in the presence of another aurora, though appears closer to the equator than where normal — often green — ones appear.

Sightings have since been reported from the UK, Canada, Alaska, northern US states and New Zealand.

As new study says the light likely appears when charged plasma from the sun hits the Earth's magnetic field in a certain way.

The Aurora Borealis, also know as the Northern Lights, are more widely seen over parts of Scotland including Shetland, Caithness and Aberdeenshire, and has even been spotted at times over northern England.

It is caused by particles from the sun blown outwards by the solar wind, striking Earth's magnetic field at the north pole and being diverted southwards to the dark side of the planet.;

In the right conditions, the Borealis is generally either green or purple, with white bursts created when the two colours merge.

Scientists are now investigating to learn more about how the two phenomena are connected.

The name Steve is reportedly in homage to a 2006 children's film Over the Hedge, where the characters give the name to a creature they have not seen before.

It was then given the "backronym" Strong Thermal Emission Velocity Enhancement (STEVE) in 2016.