English: April 15th, 2010 was the day that UK airspace fell silent as all flights were grounded by the eruption of an Icelandic volcano over a thousand kilometres away. After 200 years of sleep, Eyjafjallajökull erupted on the 15th April and caused disruption across Europe by spewing millions of tonnes of dust, ash and sulphur dioxide upwards of 35,000 feet. The blast created what is known as ‘volcanic aerosol’ - a colourful mixture of ash and sulphur compounds - in the stratosphere. This scatters an invisible blue glow which, when mixed with the red light of the setting sun, produces a colour known as ‘volcanic lavender’.

As the diffuse eruption cloud continued its journey across the UK on April 16th, 2010, a clear sky gave the sun another opportunity to illuminate the stratosphere in a glorious light show. Volcanic dust was found on cars in Sheffield and Yorkshire was treated to scenes like this magenta-hued sunset over Ilkley Moor. The BBC reported that airlines lose about £130,000,000 a day as a result of an industry-wide shutdown during events like this one.