“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)

Australian actress Joy Smithers poses beside a poster featuring Australian cricketer Brett Lee during the official launch of the AceStar underwear range at Pink Salt on August 19, 2008 in Sydney, Australia. (Photo by Mike Flokis/Getty Images)

Impala pictured in the Kruger National Park on December 7, 2007 in Mpumalanga, South Africa. (Photo by Warren Little/Getty Images)

The International Space Station (ISS) moving in front of the sun in November 2020 by astrophotographer Andrew McCarthy. These incredible photos capture the clearest images ever taken of the International Space Station (ISS) moving in front of both the moon and the sun. The photos, taken within days of one another, were captured in the space of less than a second, as the space station could be clearly seen zooming across against the bright backdrops of both moon and sun. Photographer Andrew McCarthy, from California, USA, said the photo of the ISS in front of the sun, in broad daylight, was “one of my trickiest shots ever”. (Photo by Andrew McCarthy/South West News Service)

Italy's Mount Etna, Europe's tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, Italy, February 28, 2017. (Photo by Antonio Parrinello/Reuters)

Model Irina Shayk shields herself from rain as she leaves the grand opening of Falconeri in SoHo of New York on October 16, 2019. (Photo by Backgrid USA)

Racegoers in fashionable hats attend Ladies Day at Cheltenham Festival on March 15, 2017 in Cheltenham, England. (Photo by David Davies/PA Wire)

President Woodrow Wilson speaks on telephone. Woodrow Wilson was the 28th U.S. President serving from 1913 – 1921. (Photo by Corbis)