“Mr Big Dipper”, Nicholas Roemmelt (Denmark). A stargazer observes the constellation of the Big Dipper perfectly aligned with the window of the entrance to a large glacier cave in Engadin, Switzerland. This is a panorama of two pictures, and each is a stack of another two pictures: one for the stars and another one for the foreground, but with no composing or time blending. (Photo by Nicholas Roemmelt/National Maritime Museum/The Guardian)

Protester Lauren Digioia wears police tape during an Occupy Wall Street protest in Union Square on March 19, 2012 in New York City. Protesters affiliated with the movement are gathering in Union Square today following 73 arrests at a six-month anniversary rally at Zuccotti Park over the weekend. (Photo by Mario Tama/Getty Images)

Spectators dressed as leprechauns attend St Patrick's Day parade in Dublin on March 17, 2014. (Photo by Peter Muhly/AFP Photo)

A gaggle of goslings huddle together under the protective wing of a parent along the bank of the Deschutes River as a heavy downpour passes through Bend, Oregon, late Wednesday, April, 20, 2106 afternoon. (Photo by Ryan Brennecke/The Bulletin via AP Photo)

Situated in the Pacific Ocean some 620 miles (1,000 km) from the South American continent, these 19 islands and the surrounding marine reserve have been called a unique “living museum and showcase of evolution”. Photo: “Close-up. We had a juvenile Red-Footed Booby come visit us on the sun deck. I got some closeups with my ultrawide 11-16mm Tokina”. (Photo by Carl Fredrickson)

The aurora borealis, or the northern lights occur over Derwentwater, near Keswick, England, Thursday October 8, 2015. The northern lights are the result of collisions between gaseous particles in the Earth's atmosphere with charged particles released from the sun. (Photo by Owen Humphreys/PA Wire via AP Photo)

From rural life in India to a chick growing inside its embryo and a sea turtle eating a purple jellyfish, the Society of Biology has released their stunning photography competition shortlist. Here: “Spectral Tarsier”. Tangkoko, Northern Sulawesi, Indonesia: Spectral tarsier by Wolfgang Weinhardt. (Photo and caption by Wolfgang Weinhardt/UK Society of Biology Photography Award 2014)

A round circle of smoke coming from the mouth of the Etna volcano is seen in the sky during an eruption on the southern Italian island of Sicily April 11, 2013. Mount Etna is Europe's tallest and most active volcano. (Photo by Antonio Parrinello/Reuters)