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 resident carries a gas canister as an ash cloud hovers above during an eruption of Mount Sinabung volcano at Tiga Serangkai village in Karo Regency, North Sumatra province, Indonesia June 24, 2015. More than 10,000 people from 12 villages, who are living around the slopes of Mount Sinabung, left their homes and moved to refugee camps, local media reported. (Photo by Reuters/Beawiharta)

A woman who was injured after being trampled is helped away, after residents desperate for a planned distribution of food for those suffering under Kenya's coronavirus-related movement restrictions pushed through a gate and created a stampede, causing police to fire tear gas and leaving several injured, at a district office in the Kibera slum, or informal settlement, of Nairobi, Friday, April 10, 2020. (Photo by Brian Inganga/AP Photo)

Demonstrators march in Port-au-Prince on February 14, 2021, to protest against the government of President Jovenel Moise. Several thousand people demonstrated Sunday in the Haitian capital Port-au-Prince, saying the government was trying to establish a new dictatorship and denouncing international support for President Jovenel Moise. The protests were mostly peaceful, although a few clashes broke out between some demonstrators and police, who fired tear gas and rubber bullets. (Photo by Valerie Baeriswyl/AFP Photo)

A protester wearing improvised protective headgear walks away from a cloud of tear gas on July 18, 2021 in Bangkok, Thailand. Student protesters called for a demonstration demanding the resignation of Thailand Prime Minister Prayuth Chan-o-Cha, despite a ban on gatherings because of the country's current Covid-19 outbreak, and folded a demand for better action in combating the virus into their demands. (Photo by Sirachai Arunrugstichai/Getty Images)

An injured protestor grieves in pain as police fire tear gas to disperse protesting members of the Inter University Students Federation during an anti government protest in Colombo, Sri Lanka, Thursday, May 19, 2022. Sri Lankans have been protesting for more than a month demanding the resignation of President Gotabaya Rajapaksa, holding him responsible for the country's worst economic crisis in recent memory. (Photo by Eranga Jayawardena/AP Photo)

A municipal police officer throws a stone back at protesting residents of Kampung Pulo after clashes erupted during an eviction in Jakarta, Indonesia, August 20, 2015 in this photo taken by Antara Foto. Residents facing eviction from a flood-prone part of Indonesia's capital of Jakarta clashed with police on Thursday, prompting security forces to fire tear gas and water cannon. (Photo by Muhammad Adimaja/Reuters/Antara Foto)

French riot police officers sprays pepper gas at a demonstrator during a protest against Labor Law as the Socialist government decided to force the bill through Parliament without a vote, in Paris, Thursday, May 12, 2016. France's government is facing a major test as lawmakers hold a no-confidence vote, prompted by a deeply divisive labor law allowing longer workdays and easier layoffs. (Photo by Christophe Ena/AP Photo)