Defrosting sand dunes in the Southern Hemisphere of Mars. | (NASA/JPL/University of Arizona)

A composite image of NGC 6357, a region of the galaxy that contains at least three clusters of young stars. | (X-ray: NASA/CXC/PSU/L. Townsley et al; Optical: UKIRT; Infrared: NASA/JPL-Caltech)

Saturn's main rings and its moons. | (NASA/Cassini Imaging team)

The Nili Fossae region of Mars. | (NASA/JPL-Caltech/Univ. of Arizona)

A new batch of stars are born within the constellation Vulpecula (Latin for "little fox"). | (ESA/Herschel/PACS, SPIRE/Hi-GAL Project)

The sunlit part of Jupiter and its swirling atmosphere. | (NASA/JPL-Caltech/SwRI/MSSS/Mai)

The spiral galaxy NGC 6814. | (ESA/Hubble & NASA; Acknowledgement: Judy Schmidt)

The fluted surface and elongated hills of the Medusae Fossae on Mars. | (NASA/JPL/University of Arizona)

The Milky Way's nuclear star cluster, the most massive and densest star cluster in our galaxy. | (NASA, ESA, and Hubble Heritage Team (STScI/AURA, Acknowledgment: T. Do, A.Ghez (UCLA), V. Bajaj (STScI))

An aerial view of the Sahara desert in western Libya. | (Sally Ride EarthKAM)

Star trails captured by astronauts on the International Space Station. | (NASA)

A maelstrom of glowing gas and dark dust within one of the Milky Way's satellite galaxies, the Large Magellanic Cloud. | (ESA/Hubble & NASA)