In this artist's impression supplied by the ESO (European Southern Observatory) on April 25, 2007, the planetary system around the red dwarf, Gliese 581, is pictured showing what astronomers believe is the most earth like planet found outside our solar system to date. Using the ESO 3.6-m telescope in Chile, astronomers have uncovered the planet which could have water running on its surface. The planet orbits the faint star Gliese 581, which is 20.5 light-years away in the constellation Libra. (Photo by ESO via Getty Images)

Jason Garcia poses as The Joker from Batman at the 2015 Comic-Con International in San Diego, California, July 9, 2015. (Photo by Sandy Huffaker/Reuters)

U.S. Army helicopters providing support for U.S. ground troops fly into a staging area fifty miles northeast of Saigon, Vietnam, August 28, 1966. Helicopter fuel is stored in the large rubber tanks, foreground. (Photo by Henri Huet/AP Photo)

Two Chinese farmers got more than they bargained for when they pulled up the root of a fleece flower – and came face-to-face with the doppelganger of Homer Simpson, on May 17, 2013. The large root appears to have two bulging eyes and a prominent nose – giving it an uncanny resemblance to the famous cartoon character. With two offshoot roots shaped like arms, it even looks like it is pondering or confused – just what you would expect from the real Homer. (Photo by ImagineChina)

An exhausted Rohingya refugee woman touches the shore after crossing the Bangladesh-Myanmar border by boat through the Bay of Bengal, in Shah Porir Dwip, Bangladesh, September 11, 2017. (Photo by Danish Siddiqui/Reuters)

The First U.S. Spacewalk – Gemini 4 Ed White made the United States' first spacewalk on June 3, 1965 during the Gemini 4 mission. The extra-vehicular activity (EVA) started at 19:45 UT (3:45 p.m. EDT) on the third orbit when White opened his hatch and used the hand-held manuevering oxygen-jet gun to push himself out of the capsule. (Photo by NASA)

In this Tuesday, July 29, 2014, photo, Syrian refugee Samah, 5, poses for a picture at Zaatari refugee camp, near the Syrian border, in Mafraq, Jordan. More than 2.8 million Syrian children inside and outside the country – nearly half the school-aged population – cannot get an education because of the devastation from the civil war, according to the U.N. children's agency, UNICEF. That number is likely higher, as UNICEF can't count the children whose parents didn't register with the United Nations refugee agency. (Photo by Muhammed Muheisen/AP Photo)

Cloud inversion taken at Sunrise in Mam Tor, Derbyshire, UK on August 30, 2016. (Photo by David Zdanowicz/Rex Features/Shutterstock)