Two dogs sent into outer space by the Soviet Union after their safe return to earth. They spent 22 days in orbit. (Photo by Central Press/Getty Images). 22nd March 1966

“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)

Private Harold L. Langhofer edges into the ball-turret, March 9, 1943. Curled in this position, he can turn the turret so that it fires in any direction. The turret can also be swung around so that the hatch opens into the plane, and the gunner can crawl into it while the Flying Fortress is in motion. (Photo by AP Photo)

A couple looks at their flooded street from behind their home's window in La Plata, in Argentina's Buenos Aires province, where at least 35 people were killed by flooding overnight, on April 3, 2013. (Photo by Natacha Pisarenko/Associated Press)

U.S. Air Force pilots with the Thunderbirds perform the calypso pass maneuver in F-16 Fighting Falcon aircraft during a practice session prior to the Gunfighter Skies air show at Mountain Home Air Force Base, Idaho, September 19 and released September 24, 2014. (Photo by Tech. Sgt. Manuel J. Martinez/Reuters/US Air Force)

A Rafale fighter jet flies over France's Charles de Gaulle aircraft carrier as it makes its way in the Gulf, January 28, 2016. (Photo by Philippe Wojazer/Reuters)

A Ukrainian girl plays with balloons with the colours of her country's flag aboard the Corsica Linea ferry “Mediterranee” in Marseille, southern France, on April 26, 2022. Anna and her children enjoy the sun on the deck of a ferry moored in Marseille: they are not vacationers but Ukrainian refugees who, on this boat, have finally found safety, “like in a village”, with 700 others compatriots. The “Mediterranean” usually serves Algeria, for the Corsica Linea. But it is now docked, at the Joliette ferry terminal in Marseille, with its unusual passengers. (Photo by Nicolas Tucat/AFP Photo)

A health worker shows an empty syringe after inoculating a woman with AstraZeneca's COVID-19 vaccine during the first day of a nationwide three-day vaccination drive at a school in Quezon city, Philippines on Monday, November 29, 2021. There has been no reported infection so far caused by the new variant in the Philippines, a Southeast Asian pandemic hotspot where COVID-19 cases have considerably dropped to below 1,000 each day in recent days, but the emergence of the Omicron variant has set off a new alarm. (Photo by Aaron Favila/AP Photo)