Philippe Clement / Vapour trails from aircrafts among clouds in a blue sky, France

Bryan and Cherry Alexander / Boiling water exploding into vapour and ice when thrown into cold air at -51 degrees celsius. This is because boiling water is close to a gas and breaks into tiny droplets that freeze simultaneously....

Pete Cairns / Vapour trails left in blue sky by jet aircraft. Scotland, UK

Mike Read / Aeroplane against blue sky and white vapour trail.

Bertie Gregory / 2020VISION / Adult Peregrine falcon (Falco peregrinus) flying infront of an aeroplane vapour trail, London, England, UK, June

Bryan and Cherry Alexander / Boiling water exploding into vapour and ice when thrown into cold air at -51 degrees celsius. This is because boiling water is close to a gas and breaks into tiny droplets that freeze simultaneously....

Bryan and Cherry Alexander / Boiling water exploding into vapour and ice when thrown into cold air at -51 degrees celsius. This is because boiling water is close to a gas and breaks into tiny droplets that freeze simultaneously....

Bryan and Cherry Alexander / Boiling water exploding into vapour and ice when thrown into cold air at -51 degrees celsius. This is because boiling water is close to a gas and breaks into tiny droplets that freeze simultaneously....

Philippe Clement / Vapour trails from aircraft in a blue sky at sunset, Belgium

GRAHAM HATHERLEY / Vapour trails in sky at sunset, Yosemite, California, USA

Jose B. Ruiz / Vapour trails from aircraft.