Red sky at night: The sun sets over Heathrow Airport yeserday evening as an ash cloud from an Icelandic volcano grounded all flightsThe eruption of fine ash and sulphur dioxide launched into the atmosphere by Iceland's volcano produced some spectacular sunsets across Britain last night. Now we can also look out for a real-life blue moon... and some very dirty cars.
As the volcanic clouds are carried large distance by high winds, the sulphur dioxide will react with the atmosphere to form 'sulfate aerosols', say scientists.
Just like the movies: A couple enjoy the romantic sunset at St Annes beach near Blackpool last night
A young lad packs up his rod as the sun sets on the River Tamar near Plymouth in DevonThe ash and these 'aerosols' have the effect of scattering the sun's rays so only longer light waves make it through the atmosphere, which makes the sunsets appear ruby red.
Volcanic ash can also create the appearance of a blue moon, if the particles are the right size (experts say that means one millionth of a metre or a micron).
However, ash thrown up into the atmosphere usually contains a mixture of particles with a wide range of sizes, which tends to scatter blue light so a reddish moon is more likely.
Volcanic eruptions can also have a massive effect on the weather if they are large enough. But while experts said the ash could irritate conditions such as asthma, it was not expected to cause major health problems.
Volcanologist Dr Dougal Jerram said: 'The high altitude of this plume above the UK means that it is air traffic that will suffer most.'
Weather forecaster Brendan Jones from MeteoGroup, said: 'If you look back in history there have been some periods where the weather has been changed by big volcanic eruptions like Mount Tambora and Mount St Helens.
'They have been proved to lower temperatures. There is so much ash in the atmosphere that it reduces the amount of sunlight getting to the ground.
'If the ash remains in our atmosphere for weeks or months it can reduce temperatures slightly but we are talking about fractions of degrees.'
However, experts fear the eruption of Eyjafjallajokull, which has sent this cloud of ash into the sky, could trigger a much larger explosion of nearby Mount Katla.
Katla is described as 'enormously powerful', and because it lies under a glacier its eruption would cause a huge glacial outburst flood and could spread its shadow over a much larger area.
Red glow: Sunset on Primrose Hill North london last night as the sun's rays are refracted by dust from Icelandic volcano. 
Moody: Birmingham was bathed in crimson light last night as the sun set
The Mount Tambora eruption in 1816 caused such a drop in temperatures that it became known as 'the year with no summer'.Crops failed due to low daytime temperatures, late frosts and abnormally high rainfall, provoking food riots, famine and disease.
In Ireland rain fell on 142 days that summer and across France the grape harvest was virtually non-existent.
In North America there was snow in June and lakes and rivers froze as far south as Pennsylvania during July and August.
At the moments experts say the ash could merely fall as 'dirty rain' in a couple of days, which would mean a trip to the car wash. A positive side effect is the ash could be good for the soil in gardens.
Meanwhile skywatchers can look forward to stunning light displays as the ash spreads high in the atmosphere.
Robin Scagell, of the UK's Society for Popular Astronomy, said today: 'Be ready to enjoy some dazzling arrays of colours especially purples and reds looking much stronger than usual
Dramatic: Volcanic ash can bring out dramatic pinks and purples during sunset, as shown by the latest erupting volcano in Iceland'The most amazing sunsets I've ever seen were in Australia after the El Chichon volcano went off in Mexico in 1982. The sky turned an intense purple and even the moon turned blue. We may also see a phenomenon called a Bishop's Ring - a huge brown or blue halo around the sun that was first noticed when the Krakatoa volcano exploded in 1883.
'So if it is clear, go out and enjoy some stunning natural light shows.'
In 2004, art experts suggested that the vivid skies painted in Edvard Munch's famous painting The Scream were a record of the effects of the Krakatoa eruption in Java half-way around the world in Norway in 1883.
Munch said at the time: 'Suddenly the sky turned blood red. I stood there shaking with fear and felt an endless scream passing through nature.'
source :dailymail
