Scientist Vladimir Surdin believes 'silver clouds' were the cause of the multi-coloured night sky witnessed by thousands of people.
'So far it is hard to say what exactly it was. During last night our stations did not register any abnormal magnetic storms which must accompany the North Lights', Chelyabinsk Hydro-Meteorological Centre said
Thouands of people witnessed the eerie spectacle in Chelyabinsk and plus towns and villages over hundreds of kilometres in the region. Social sites buzzed comments on the strange multi-coloured phenomenon which was visible to some people for several hours started around 2am
Some believed they saw the ghostly face of a dog in the in the blue, white, red and yellow hue that lit up the dark sky.
The lights were clearly visible from many parts of the Urals city with the best view in the district around Chelyabinsk tractor factory.
The footage here was seen from nearby Miass town, some 96km west of Chelyabinsk, which many reported was where the night show was at its strongest.
The man who shot the footage says: 'This video is recorded at 2 am on the 16 June 2013. The sky over the town of Miass at 2 am was emblazoned with blue light. It unclear what kind of natural phenomenon it is. The glowing continues and just what it will end up with no-one knows'.
'This video is recorded at 2 am on the 16 June 2013. The sky over the town of Miass at 2 am was emblazoned with blue light...'
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Some witnesses claimed the lights resembled the reflection on clouds of powerful searchlights but there are no known lights of this kind in the region.
Scientists gave two versions. One, they claimed it could be a rare case of the Northern Lights being witnessed much further south than normal.
Yet at around 55 degrees north, this is outside the normal regions where the Northern Lights are seen by some 2,000 km. It is the same latitude as Jutland in Denmark, Newcastle-upon-Tyne in England, and Prince of Wales Island in the extreme south of Alaska.
The second theory is a phenomenon known as 'silver clouds'.
These are very high clouds, some 85km above the ground, which can be visible at night if the sun suddenly catches them.
Chelyabinsk Hydro-Meteorological Centre said: 'So far it is hard to say what exactly it was. During last night our stations did not register any abnormal magnetic storms which must accompany the North Lights.
'But the idea about silver clouds must be checked too. Normally they are not visible from ground. We shall be able to understand the nature of this lights only when we carefully study photo and video taken last night'.
Regional TV reported: 'At first it appeared like white-blue shining light, later dirty red and yellow colours came out. The lights were completely gone by the dawn.'
One blogger said his grandmother had seen a similar phenomenon in the Chelyabinsk sky in 1957.
Witness Alexander Kazantsev said: 'I was walking back home with my friends at Lenina Prospekt when we saw the lights in the sky. At first we thought it was yet another meteorite flying towards us, then we thought about a strong searchlight.
'But the coloured stripes were stable. Now I am sure it was a North Lights event. As far as I remember nothing like this even happened in Chelyabinsk'.
The last time the region experienced a light show was on 15 February when a meteorite stuck Chelyabinsk, causing shock and awe.
Scientist Vladimir Surdin from Stenberg Astronomical Institute in Moscow believes 'silver clouds' were the cause of the multi-coloured night sky.
They form in mesosphere at a height of 80-90 km and are usually seen when sun rays light them up while the lower parts of the atmosphere are already in darkness. He suggested that the phenomenon - also visible in Moscow - can be seen around four times a year in the Chelyabinsk region.
'You can usually see the 'silver clouds' around the summer solstice period, and after the sunset,' said the senior researcher.
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