A Ukrainian serviceman of the 53rd brigade fires a RPG-9 towards Russian positions at the frontline close to Donetsk, Ukraine, Saturday, August 19, 2023. (Photo by Libkos/AP Photo)

Rescuers work to put out fire outside a damaged residential building hit by recent shelling in the course of Russia-Ukraine conflict in Donetsk, Russian-controlled Ukraine on November 7, 2023. (Photo by Reuters/Stringer)

A woman dressed as an angel takes a break from greeting children at a public library in Irpin, northwest of Kyiv, on December 23, 2022, amid the Russian invasion of Ukraine. (Photo by Genya Savilov/AFP Photo)

A mural depicting a resting cat by Russian street artist Vladi is photographed by a man outside a hotel in Hong Kong on November 27, 2023. (Photo by Peter Parks/AFP Photo)

Ukrainian soldiers of the 71st Jaeger Brigade fire a M101 howitzer towards Russian positions at the frontline, near Avdiivka, Donetsk region, Ukraine, Friday, March 22, 2024. (Photo by Efrem Lukatsky/AP Photo)

A Ukrainian serviceman stands on a flag of Russia's mercenary group Wagner near the Russian border in Sumy region, Ukraine on August 13, 2024. (Photo by Viacheslav Ratynskyi/Reuters)

This image taken from video provided by TVBS shows a commercial airplane clipping an elevated roadway just before it careened into a river in Taipei, Taiwan, Wednesday, February 4, 2015. The ATR-72 prop-jet aircraft had 58 people aboard. (Photo by AP Photo/TVBS)

“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)