“Contrails (short for “condensation trails”) or vapour trails are artificial clouds that are the visible trails of condensed water vapour made by the exhaust of aircraft engines. As the hot exhaust gases cool in the surrounding air they may precipitate a cloud of microscopic water droplets or, if the air is cold enough, tiny ice crystals”. – Wikipedia

Photo: An airplane leaves a vapor trail as it flies in front of he moon on January 17, 2007 above Hanover, Germany. (Photo by Alexander Hassenstein/Getty Images)

A pheasant stands in snow near Dulverton on January 30, 2012 on Exmoor, England. After unseasonably mild winter weather, some parts of the UK woke to a covering of snow as a cold spell of weather sets in, with forecasters warning temperatures are set to plunge as the week progresses. (Photo by Matt Cardy/Getty Images)

A man protesting the Ferguson grand jury decision to not indict officer Darren Wilson in the Michael Brown case is arrested while marching through the streets on December 1, 2014 in New York City. Brown, an 18-year-old black man, was killed by Darren Wilson, a white Ferguson, MO police officer, on August 9. (Photo by Andrew Burton/Getty Images)

Two pins featuring former North Korean leader Kim Il Sung wearing different facial expressions are displayed in a glass case of Thomas Hui at his apartment in Hong Kong, China April 11, 2016. Collector Thomas Hui, 37, a former bank employee in Hong Kong, who is fascinated by North Korean pins and badges, has gathered over 100 featuring former leaders Kim Il Sung and Kim Jong Il, and has been buying and trading these Communist accessories since 2008. (Photo by Bobby Yip/Reuters)

Residents display scarecrows with an NHS theme outside their homes in Greenfield for the annual scarecrow parade on April 09, 2020 in Manchester, United Kingdom. There have been around 60,000 reported cases of the COVID-19 coronavirus in the United Kingdom and 7,000 deaths. The country is in its third week of lockdown measures aimed at slowing the spread of the virus. (Photo by Anthony Devlin/Getty Images)

A pair of Easter bunnies socialise in the sunshine on April 4, 2021 in Brighton, United Kingdom. Earlier this week, the UK government eased rules on socialising, permitting groups of six people (or more if limited to two households) to meet outdoors. The latest lockdown measures were imposed at the end of last year to curb a surge in Covid-19 cases. (Photo by David McHugh/Brighton Pictures)

A cleaning staff waers protective gear to disinfect a metro carriage as a prevemtive measure against the spreading of the COVID-19 coronavirus in Addis Ababa, Ethiopia, on March 20, 2020. African countries have been among the last to be hit by the global COVID-19 coronavirus epidemic but as cases rise, many nations are now taking strict measures to block the deadly illness. (Photo by Michael Tewelde/AFP Photo)

A Muslim worshipper attends a mass prayer against COVID-19, the new coronavirus, in Dakar on March 4, 2020, after two cases were confirmed in Senegal in the previous days. Across the world, 3,155 people have died from the virus. More than 92,723 have been infected in 78 countries and territories, according to AFP's latest toll based on official sources at 1700 GMT on March 3, 2020. (Photo by John Wessels/AFP Photo)