PIX4671636: Noctulescent clouds - Noctilucent clouds - Noctilucent clouds, very high altitude clouds, photographs in July 2009 in Russia. These rare clouds are called noctilucent or “” night shining” as they seem to glow in the dark. They are caused by ice crystals at about 80 km altitude. These crystals reflect sunlight when the sun is well below the horizon. They are properly known as polar mesospheric clouds and are under intense study as it remains a mystery as to how they are formed. Image taken in july 2009 in Russia / Bridgeman Images
LRI4671689: Illuminated page of the Bible Cervara redigee in Hebrew, 1299-1300 (Cervera Bible is a manuscript on parchment in Hebrew language and characters executed in Cervera (Lerida, Spain) in 1299-1300) Biblioteca Nacional de Portugal, Lisbon, (Ms IL 72), Jewish School, (14th century) / Bridgeman Images