Sky-gazers in Denmark were in for a treat this week, as stunning ‘veins of heaven’ clouds appeared over the country.
Photographer Ruslan Merzlyakov snapped an incredible photo of the rare phenomenon over Nykobing Mors, and NASA has now featured the photo as its Astronomy Picture of the Day.
NASA explained: “Transfusing sunlight through a darkened sky, this beautiful display of noctilucent clouds was captured earlier this week, reflected in calm waters from Nykobing Mors, Denmark.
“From the edge of space, about 80 kilometers above Earth’s surface, the icy clouds themselves still reflect sunlight, though the Sun is below the horizon as seen from the ground.”
These clouds, also known as polar mesospheric clouds or noctilucent clouds, are usually spotted at high latitudes, according to NASA.
It added: “Usually spotted at high latitudes in summer months the night shining clouds have made an early appearance this year as northern nights grow short.”
According to the Met Office, these clouds are ‘extremely rare.’
The Met Office said: “Noctilucent clouds are extremely rare collections of ice crystals, occasionally appearing in late clear summer evenings after sunset, but before it gets completely dark.
“They become visible about the same time as the brightest stars appear and often stay visible after dark because they are still reflecting sunlight due to their great height.
“They are higher up than any other clouds, occupying the layer of atmosphere known as the Mesosphere, and are only seen at latitudes between 45°N and 80°N in the Northern Hemisphere, and equivalent latitudes in the southern hemisphere.
“They are seen less often in the southern hemisphere as there is very little land and very few people there. Only the southern tip of Argentina and Chile, and the Antarctic are at the correct latitude”