The sky turned bright red across parts of England on Monday, October 16 triggering alarm on social media.
Red sun over #Bristol today… weird! pic.twitter.com/EImntppYnk— Camilla Pearce (@camillapearce) 16 October 2017
The phenomenon was spotted from as far south as Plymouth and as far north as Newcastle and was clearly visible in London.
One theory was that it was caused by Hurricane Ophelia sucking up dust from the Sahara and making the sky take on a scarlet sheen.
People reacting to a bit of Saharan sand in the sky like #redsun pic.twitter.com/BpLKadR47W— David Goodwin (@LDN_TUBE) October 16, 2017
Forest fires in Portugal and Spain, which have killed 31 people, are also believed to be a contributing factor.
Caused by Saharan dust being drawn northwards by #Ophelia, we have welcomed an incredibly beautiful #RedSun on campus today. pic.twitter.com/KXipQVKRXb— Uni of Manchester (@OfficialUoM) October 16, 2017
The dust makes blue light, which has a shorter wavelength, scatter and therefore appear red.
The Met Office said the "vast majority" of the dust was caused by forest fires in Iberia and smoke and fire debris had been dragged north by Hurricane Ophelia.
#Ophelia has drawn Saharan dust north to the UK, making the sun appear red this morning. Photo credit: Kelly Norris https://t.co/2qMvYSQjLQ pic.twitter.com/7dioN4vj61— Met Office (@metoffice) October 16, 2017
An #amber weather warning for Ex-Hurricane #Ophelia has been issued, but what does that mean? Stay #weatheraware https://t.co/EFVGlpF0N1 pic.twitter.com/dpFKpp5XD6— Met Office (@metoffice) October 16, 2017
But many people on social media had more fanciful theories.
Some claimed it signalled the coming of Azor Ahai, a legendary warrior from Game Of Thrones.
I've worked out this whole red sun thing… AZOR AHAI will be born today! #GameOfThrones #RedSun pic.twitter.com/sb7hf3u5IE— Drawty Devil (@DrawtyDevil) 16 October 2017