The possible surface of TRAPPIST-1f, one of seven newly discovered planets in the TRAPPIST-1 system that scientists using the Spitzer Space Telescope and ground based telescopes have discovered. (Photo by Reuters/NASA/JPL-Caltech)

Indonesian soldiers take part in a handling riots practice ahead of the elections at their military home base in Banda Aceh, Aceh province on April 9, 2019. (Photo by Chaideer Mahyuddin/AFP Photo)

A vendor prepares paan, a betel nut-based chewable stimulant at a flower market in Kolkata, India, January 18, 2016. (Photo by Rupak De Chowdhuri/Reuters)

Smoke and flames rise over a warehouse storing ammunition for multiple rocket launcher systems at a military base in the town of Kalynivka in Vinnytsia region, Ukraine September 27, 2017. Ukrainian officials say they have evacuated more than 30,000 people after a fire and ammunition explosions, at the military base on Tuesday. (Photo by Gleb Garanich/Reuters)

Ukrainian servicemen sit atop an armored personnel carrier (APC) at a military base in the town of Kramatorsk, eastern Ukraine, December 24, 2014. (Photo by Valentyn Ogirenko/Reuters)

A man dressed as Santa Claus poses during a base flying event in downtown in Berlin December 6, 2014. Participants of the event hosted by entertainment agency Jochen Schweizer flew down 98 metres (322 ft.) from atop the hotel in the German capital. (Photo by Hannibal Hanschke/Reuters)

NATO and U.S. flags flutter as U.S. Air Force F-22 Raptor fighter flies over the military air base in Siauliai, Lithuania, April 27, 2016. (Photo by Ints Kalnins/Reuters)