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 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)

The Hubble Space Telescope is shown following its release from the space shuttle Discovery Wednesday, February 19, 1997. The Hubble Space Telescope, one of NASA'S crowning glories, marks its 25th anniversary on Friday, April 24, 2015. With more than 1 million observations, including those of the farthest and oldest galaxies ever beholden by humanity, no man-made satellite has touched as many minds or hearts as Hubble. (Photo by AP Photo/NASA)

Ice Age – Tibet, China. “This is the Chinese version of the blue ice lake, Pumoungcuo, at an altitude of 5,070 metres (16,600 feet). This lake in Tibet freezes every winter. At night, under the low temperatures of -20C, you can listen to the sound of the ice cracking while capturing the most beautiful winter sky. The blue ice surface and dazzling Orion constellation create a fantasy landscape. I felt so happy to have the stars as my companion on this magical night”. (Photo by Daniel Zafra Portill/Milky Way Photographer of the Year)

The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)

Sharafkhaneh port and lake Urmia. Masoud Ghadiri (Iran). The summer Milky Way is very prominent in this photo. On the galaxy zone, Saturn is located besides the Lagoon nebula. On the right of the horizon, you can see the extreme light pollution of Urmia, which is caused by ever-increasing city development. (Photo by Masoud Ghadiri/National Maritime Museum)

An Afghan teacher, in brown, helps school children run from the site of clashes near the Pakistan consulate in Jalalabad, capital of Nangarhar province, Afghanistan, Wednesday, January 13, 2016. Several members of the Afghan security forces were killed Wednesday after unidentified gunmen attacked the Pakistani consulate in a volatile eastern province, an official said on Wednesday. (Photo by Mohammad Anwar Danishyar/AP Photos)

Listed as endangered on the IUCN red list of threatened species, a humphead wrasse, or Napoleon fish, swims in an aquarium during an event in Tokyo's shopping district of Ginza on August 5, 2019. (Photo by Kazuhiro Nogi/AFP Photo)