Alphajet aircraft draw a heart-shaped message in the sky during the 2010 presentation show of the French aerobatics team Patrouille de France, over the French city of Salon-de-Provence. (Photo by Gerard Julien/AFP Photo)

A balloon depicting the face of alien movie character E.T. is seen in the sky at the 15th Solar Balloon Festival in Envigado, Colombia December 31, 2015. (Photo by Fredy Builes/Reuters)

The Aurora Borealis (Northern Lights) is seen over the sky near the village of Pallas (Muonio region) of Lapland, Finland September 8, 2017. (Photo by Alexander Kuznetsov/Reuters)

Sky attends the 2018 MTV Video Music Awards at Radio City Music Hall on August 20, 2018 in New York City. (Photo by Stephen Lovekin/Rex Features/Shutterstock)

The northern lights, or aurora borealis, appear in the sky over the Bamburgh lighthouse at Stag Rock in Northumberland, England on September 28, 2016. (Photo by Owen Humphreys/PA Wire via ZUMA Press)

In this Wednesday, July 23, 2014 file photo, Omaha photographer Lane Hickenbottom photographs the night sky in a pasture near Callaway, Neb. With no moon in the sky, the Milky Way was visible to the naked eye. More than one-third of the world’s population can no longer see the Milky Way because of man-made lights, according to a scientific paper by Light Pollution Science and Technology Institute's Fabio Falchi and his team members, published on Friday, June 10, 2016. (Photo by Travis Heying/The Wichita Eagle via AP Photo)

A Hot air balloon is seen at the Cup Hot Air event during the Air Sports festival titled “70 Years of Peaceful Sky” in Minsk, Belarus July 18, 2015. (Photo by Vasily Fedosenko/Reuters)

Firework display from the top of the Sky Tower to welcome the New Year on January 1, 2015 in Auckland, New Zealand. (Photo by Dave Rowland/Getty Images)