Soap Bubble Structures by Kym Cox. Bubbles optimise space and minimise their surface area for a given volume of air. This phenomenon makes them a useful tool in many areas of research, in particular, materials science and “packing” – how things fit together. Bubble walls drain under gravity, thin at the top, thick at the bottom, which interferes with travelling lightwaves to create bands of colour. Black spots show the wall is too thin for interference colours, indicating the bubble is about to burst. (Photo by Kym Cox/2019 Science Photographer of the Year/RPS)

Riders pray before competing at a rodeo event in Monte Negro, south of the Amazon basin, Rondonia state, Brazil on August 30, 2019. In recent years, Monte Negro has expanded as a key cattle town with a strong cowboy culture. (Photo by Carl De Souza/AFP Photo)

This week's full Moon as photographed from on board the International Space Station by NASA astronaut Jeff Williams on August 19, 2016. Jeff is currently Commander of the Space Station for the Expedition 48 crew. (Photo by Jeff Williams/NASA)

An Indian bride adjusts her veil during a mass marriage ceremony in Ahmadabad, India, Sunday, October 11, 2015. Sixty five Muslim couples tied the knot in a single ceremony organized by a social organization. (Photo by Ajit Solanki/AP Photo)

A students with her face smeared in coloured powder, celebrates Holi at a university campus in Chandigarh, India March 23, 2016. (Photo by Ajay Verma/Reuters)

A rickshaw driver looks out the windshield as he drives onto the highway in Mardan, Pakistan January 30, 2017. (Photo by Fayaz Aziz/Reuters)

Ant Burgess practices his freestyle on a jet ski at Blyth beach in Northumberland, on the North East coast on Saturday, April 10, 2021. (Photo by Owen Humphreys/PA Images via Getty Images)

A handout photo made available by Jose Juan Rodriguez Rocha, on 17 November 2021 shows lightning over Cumbre vieja Volcano as seen from El Paso, La Palma, Canary Islands Spain, 14 November 2021. The lightning over a volcano is sometimes seen due to the charge of electricity caused by the friction of the expelled particles within the column of ashes and pyroclastic rocks. (Photo by Jose Juan Rodríguez Rocha/EPA/EFE)