Why are there pink skies in Greater Manchester?

A mysterious pink glow has been snapped across the night skies of Greater Manchester - with much speculation about its cause.

Despite being mistaken for the famous Northern Lights, the pink skies that have been spotted over Bolton and Manchester are not in fact the product of a natural phenomenon.

The unusual spectacle is actually being caused by LED lights used to boost the quality of pitches at Manchester City's Ethihad and Joie Stadiums, and the Toughsheet Community Stadium, home to Bolton Wanderers.

"There were a few smiles when we heard about the Northern Lights rumours," Bolton's head groundsman Chris Simm told BBC Manchester. "But the glow over the stadium is strictly business!"

"The grass needs light and warmth to photosynthesise," Simm explained.

"The high stands here offer brilliant views for our fans but they block natural sunlight from hitting the turf.

"That shade is our biggest enemy and we use the rigs to counter it.

"We target the high-wear areas first, specifically the goalmouths and warm-up zones, before treating the whole pitch as the temperatures drop.

"Modern expectations for pitch quality are incredibly high.

"Without these units, we could not produce a surface suitable for professional football, week in, week out.

"It is the only way to keep the grass growing when nature wants it to sleep.

"We are essentially replicating a summer's day in the middle of a Lancashire winter."

Football clubs have used lighting rigs for many years, but the distinctive pink colour being spotted is a result of updated technology - with the latest research showing the most effective combination of colours for imitating sunlight produces a pink glow.