Earth’s global surface temperatures in 2018 were the fourth warmest since 1880, according to independent analyses by NASA and the National Oceanic and Atmospheric Administration (NOAA).

NASA's Atmospheric Infrared Sounder (AIRS) instrument captures a polar vortex moving from central Canada into the U.S. Midwest from January 20 through January 29.

This particularly dramatic picture was taken with the moon over Lake Maggiore, the second largest lake in Italy and the largest in southern Switzerland.

This ethereal image captures a beautiful scene at the Earth's South Pole in Antarctica, where the dry, cold conditions allow for observations of a number of rare celestial phenomena that are seen far less often elsewhere.

This image from ESA's Mars Express shows Korolev crater, an 82-kilometer-across feature found in the northern lowlands of Mars.

Fifty years ago on Dec. 21, 1968, Apollo 8 launched from Pad A, Launch Complex 39, Kennedy Space Center at 7:51 a.m. EST.

The Washington National Cathedral is seen lit up with space imagery prior to the Smithsonian National Air and Space Museum's Spirit of Apollo event commemorating the 50th anniversary of Apollo 8 on Dec. 11, 2018, in Washington, D.C.

International Space Station Commander Alexander Gerst viewed SpaceX's Dragon cargo craft chasing the orbital laboratory on Dec. 8, 2018.

Three crew members are adjusting to life on the International Space Station after a successful launch and docking of their Russian Soyuz MS-11 spacecraft on Dec. 3, 2018.

On Nov. 26, 2018, Mars received its newest robotic resident. NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander successfully touched down on the Red Planet after an almost seven-month, 300-million-mile (458-million-kilometer) journey from Earth.