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)

A fighter of Libyan forces allied with the U.N.-backed government fires a shell with Soviet made T-55 tank at Islamic State fighters in Sirte, Libya, August 2, 2016. (Photo by Goran Tomasevic/Reuters)

Iraqi forces gather during an operation to attack Islamic State militants in Mosul, Iraq, October 21, 2016. (Photo by Reuters/Stringer)

Plebes form a human pyramid to place an upperclassman hat atop the 21-foot vegetable shortening-covered Herndon Monument, a tradition marking the end of their plebe year at the U.S. Naval Academy in Annapolis, Maryland, U.S., May 23, 2022. (Photo by Kevin Lamarque/Reuters)

Party-loving Brits headed out to enjoy the first weekend of indoor drinking in months; many – like these lasses in Liverpool on May 22, 2021 – were keen to make up for lost time. (Photo by London News Pictures)

This handout photo taken on August 31, 2023 and provided by the South Korean Defence Ministry shows South Korean soldiers participating in an air assault drill at a training field in Jangseong, as part of the annual Ulchi Freedom Shield joint military drills between South Korea and the United States. (Photo by Handout/South Korean Defence Ministry/AFP Photo)

Sun Model students pose for a photo during a training session at the school on March 31, 2014 in Phnom Penh, Cambodia. Having started in August 2010 with only three models, the Sun Model Agency and School is starting to make an impact in the fashion industry in Cambodia. (Photo by Omar Havana/Getty Images)

Guests attend preview event for “Candytopia”, the outrageously interactive candy wonderland, opening in San Francisco, USA on September 6, 2018. (Photo by Kelly Sullivan/Getty Images for Candytopia)