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)

An instructor (C) adjusts the posture of students of flight attendant major during a training session at Anhui Foreign Languages University, in Hefei, Anhui province, China, May 25, 2015. (Photo by Reuters/China Daily)

A woman wearing a face mask as a precaution against the COVID-19 while using smartphone in a subway train in Hong Kong, Thursday, February 27, 2020. As the worst-hit areas of Asia continued to struggle with a viral epidemic, with hundreds more cases reported Thursday in South Korea and China, worries about infection and containment spread across the globe. (Photo by Kin Cheung/AP Photo)

A United States Secret Service agent fights with the wind as Marine One with United States President Joe Biden on board departs from the White House in Washington to Ottawa, Canada on March 23, 2023. (Photo by Rex Features/Shutterstock)

A model presents a creation from the Gucci Fall-Winter 2022/2023 collection during Fashion Week in Milan, Italy, February 25, 2022. (Photo by Alessandro Garofalo/Reuters)

A woman attempts to get past a police blockade during a protest on Women's Day, in Manila, Philippines on March 8, 2023. (Photo by Lisa Marie David/Reuters)

People enjoy their time during the last day of the Dubai Expo 2020 in Dubai, United Arab Emirates, Thursday, March 31, 2022. The world's fair in Dubai, the pandemic-delayed Expo 2020, closed on Thursday after six months of concerts, conferences and festivities. (Photo by Ebrahim Noroozi/AP Photo)

A Kenyan police officer calls for reinforcement in front of a lorry set on fire by protesters during riots in the informal settlement of Kibera in Nairobia on May 2, 2023. Kenyan riot police were out on the streets on May 2, 2023 as the opposition defied a police ban and staged new demonstrations over the cost of living crisis and last year's election results. (Photo by Luis Tato/AFP Photo)