Noctilucent clouds over Moscow
© Via Twitter@xufospace
Night clouds can be seen in about an hour after sunset, said the head of the Hydrometeorological Center of Russia

Unusual noctilucent clouds can be seen in the night sky over Moscow. This was announced on Wednesday TASS director of the Hydrometeorological Center of Russia Roman Vilfand.

He noted that this phenomenon is a beautiful decoration in Summer sky. Such clouds can be observed on 4 and 5 July in the clear sky at night.

"These clouds are visible at night, they are often also called nocturnal clouds They are silvery and beautifully lit at night. When the sun sets, its rays penetrate deep into the atmosphere, penetrating it with light." - Vilfand said.

According to him, the noctilucent clouds are a cluster of molecules of water vapor. "These clouds are very high, at a distance of about 100 km from the surface of the Earth. To predict their occurrence can not be because we do not understand their nature. They appear in the summer, and the nature of these clouds is not fully known..." said Vilfand.

According to experts, noctilucent clouds can admire about an hour after sunset. An hour before sunrise, they disappear again. They first appear in the northwest, and then, after the middle of the night, they are best seen in the north-east. In Moscow latitudes they are best seen in early July.