The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)

Growing cities, overuse of fertilizers and factory wastewater have degraded China's water supplies to the extent that half the nation's rivers and lakes are severely polluted. China aims to spend $850 billion to improve filthy water supplies over the next decade, but even such huge outlays may do little to reverse damage caused by decades of pollution and overuse in Beijing's push for rapid economic growth. Photo: Fishermen row a boat in the algae-filled Chaohu Lake in Hefei, Anhui province, June 19, 2009. (Photo by Jianan Yu/Reuters)

It’s a classic tale of dictatorship gone wrong and the fight for freedom. Like in any good battle, there’s fire, albeit from firecrackers, but the ammunition in this one is – flour. It takes place in a Hemingway-esque Spanish village. The battle of “Enfarinats” in celebration of the Els Enfarinats festival, rages on on December 28, 2012 in Ibi, Spain. Citizens of Ibi annually celebrate the festival with a fight using flour, eggs and firecrackers. The battle takes place between two groups, a group of married men called “Els Enfarinats” who take the control of the village for one day pronouncing a number of ridiculous laws and fining the citizens that infringe them and a group called “La Oposicio” who try to restore order. At the end of the day the money collected from the fines is donated to charitable causes in the village. The festival has been celebrated since 1981 after the town of Ibi recovered the tradition but the origins remain unknown.

Photo: A Reveller smokes during the battle of “Enfarinats”, a flour fight in celebration of the Els Enfarinats festival. (Photo by David Ramos)

“A fter the former Soviet Union conducted its first nuclear test in August 1949, the US reevaluated its postwar defense policies. With the US monopoly on atomic weapons broken, military and political leaders chose to diversify the American stockpile by developing thermonuclear and tactical nuclear weapons. One of the more interesting concepts to come out of this period was atomic artillery, which was successfully tested at the Nevada Proving Grounds (now the Nevada Test Site) in May 1953”. – Alan Carr. Photo: Atomic Annie at work during the Upshot-Knothole test series, 1953. (Photo by Los Alamos National Laboratory/US Army)

China has sent its first woman into space on a mission to dock with an orbiting station, the latest step in an ambitious programme to go to the moon and on to Mars.

Photo: China's first female astronaut Liu Yang, waves during a sending off ceremony before she departs for the Shenzhou 9 spacecraft rocket launch pad at the Jiuquan Satellite Launch Center in Jiuquan, China, Saturday, June 16, 2012. China will send its first woman and two other astronauts into space Saturday to work on a temporary space station for about a week, in a key step toward becoming only the third nation to set up a permanent base in orbit. (Photo by Ng Han Guan/AP Photo)

Mark Taylor may not have any training as a photographer, but that doesn’t stop him from taking amazing animal photos. From his studio in Southeast England, Taylor has made a big business out of photographing man’s best friends, following in the footsteps of his late mother, Jane Burton. Most of the animals he works with are babies, who are more comfortable in front of the camera than older animals.

Photo: Taylor often uses animals that belonged to friends of his late mother, including this Italian Spinone puppy chewing his tail. Baby animals make ideal subjects, as the older dogs and cats get, the warier they are of spending time in a studio. And his trick for getting this small subject to pose? Dog treats, of course. (Photo by Mark Taylor/Rex Features)

The best man in a wedding party, who all declined to be identified, stands near the bride and groom as he holds an AR-10 rifle he was handed while the party was having their pre-wedding portraits taken on the steps of the capitol before a rally nearby by gun-rights advocates to protest a new expanded gun background check law in Washington state Saturday, December 13, 2014, in Olympia, Wash. The wedding party was not part of the protest, but posed for pictures with it after being handed it by gun activist Brandon Lyons, who said “we've all just broken the law”, by handing the gun over. Saturday's protest was called the “I Will Not Comply” rally, and those attending said they will openly exchange firearms in opposition to the state's new voter-approved universal background check law, Initiative 594. The law, which took effect on December 4, requires background checks on all sales and transfers, including private transactions and many loans and gifts. (Photo by Elaine Thompson/AP Photo)

Hundreds of houses painted in bright colors in what organizers claim is Mexico's largest mural, is part of a government-sponsored project is called Pachuca Paints Itself, in the Palmitas neighborhood, in Pachuca, Mexico, Thursday, July 30, 2015. German Crew is the artist collective responsible for painting the mural project. Director Enrique Gomez, who goes by MYBE, said the crew has painted 1,500 square meters with 20,000 liters of paint. Working hand-in-hand with residents, muralists have painted the facades of 200 homes bright lavender, lime green, incandescent orange – hues more commonly found in a bag of Skittles than in the drab, cement-and-cinderblock neighborhoods where many of Mexico's poor live. The project aims to bring the community together and rehabilitate the area. (Photo by Sofia Jaramillo/AP Photo)