Saturn’s rings display their subtle colors in this view captured on Aug. 22, 2009, by NASA’s Cassini spacecraft. http://www.nasa.gov/sites/default/files/thumbnails/image/pia22418-1041.jpg

As our nearest star, the Sun bathes Earth in a steady stream of energetic particles, magnetic fields and radiation that can stimulate our atmosphere and light up the night sky, like the aurora borealis, or northern lights. http://www.nasa.gov/sites/default/files/thumbnails/image/northamerica_vir_2018111_lrg.jpg

NASA astronaut Ricky Arnold captured this clear view of Mount Rainier National Park as the International Space Station orbited above, sharing the image with his followers on April 25 to celebrate National Park Week. http://www.nasa.gov/sites/default/files/thumbnails/image/dbpbyitxcaa5ttg.jpg_orig.jpg

Greece and the Aegean and Ionian Seas http://www.nasa.gov/sites/default/files/thumbnails/image/iss055e008381.jpg

NASA's Operation IceBridge successfully collected data over several glaciers, research sites, and some parallel coastal grid lines on April 26, 2018, as part of its Spring 2018 campaign. http://www.nasa.gov/sites/default/files/thumbnails/image/valley.jpg

Far across the solar system, where Earth appears merely as a pale blue dot, NASA’s Galileo spacecraft spent eight years orbiting Jupiter. Newly resurrected data from Galileo's first flyby of Jupiter's moon Ganymede is yielding new insights. http://www.nasa.gov/sites/default/files/thumbnails/image/imgpsh_fullsize.jpeg

NASA's InSight Mars mission will help scientists understand the processes that shaped the rocky planets of the inner solar system (including Earth) more than four billion years ago. InSight, the first planetary mission to take off from the West Coast, is targeted to launch Saturday, May 5 from Vandenberg Air Force Base in California. http://www.nasa.gov/sites/default/files/thumbnails/image/insight_solar_array_panel_main-full.jpg

The lone active region visible on our Sun put on a fine display with its tangled magnetic field lines swaying and twisting above it (Apr. 24-26, 2018) when viewed in a wavelength of extreme ultraviolet light. http://www.nasa.gov/sites/default/files/thumbnails/image/pia22449.jpg

NASA's InSight spacecraft rests aboard a ULA Atlas V rocket, awaiting launch scheduled on May 5, 2018. http://www.nasa.gov/sites/default/files/thumbnails/image/41876495681_24bd386693_k.jpg

Astronaut-educator Ricky Arnold conducts student-designed science on the Space Station. http://www.nasa.gov/sites/default/files/thumbnails/image/rickyarnold.jpg

Warm air and sunlight beget warmer ocean waters and provoke blooms of the “grass of the sea”—phytoplankton. http://www.nasa.gov/sites/default/files/thumbnails/image/northsea_oli_2018125_lrg.jpg

The crew of the International Space Station snapped this image of the full moon on April 30, 2018, as the station orbited off the coast of Newfoundland, Canada. http://www.nasa.gov/sites/default/files/thumbnails/image/iss055e043612.jpg

In the darkness of the distant universe, these galaxies resemble glowing fireflies, flickering candles, charred embers floating up from a bonfire, and light bulbs softly shining. http://www.nasa.gov/sites/default/files/thumbnails/image/potw1819a.jpg

Galileo Galilei discovered Jupiter's moon Europa in 1610. More than four centuries later, astronomers are still making discoveries about its icy surface. http://www.nasa.gov/sites/default/files/thumbnails/image/europa_0.jpg

Each and every day NASA's Solar Dynamics Observatory (SDO) observes our Sun and relays observational data to scientists on Earth. http://www.nasa.gov/sites/default/files/thumbnails/image/sun_0.jpg

This image of the southern Greenland town of Narsaq was taken during an Operation IceBridge flight on Apr. 26, 2018. http://www.nasa.gov/sites/default/files/thumbnails/image/41959302461_15269fcfff_o.jpg

Astronaut Ricky Arnold took this selfie during the May 16, 2018, spacewalk. http://www.nasa.gov/sites/default/files/thumbnails/image/iss055e071596.jpg

NGC 1032 cleaves the quiet darkness of space in two in this image from the NASA/ESA Hubble Space Telescope. http://www.nasa.gov/sites/default/files/thumbnails/image/potw1820a.jpg

An Orbital ATK rocket rolls out to launch Pad-0A at NASA's Wallops Flight Facility on May 17, 2018, in advance of a May 21 launch from Wallops Island, VA. The Antares will launch a Cygnus spacecraft on a cargo resupply mission to the International Space Station. http://www.nasa.gov/sites/default/files/thumbnails/image/nhq2018051700452.jpg

The Orbital ATK Antares rocket, with the Cygnus spacecraft onboard, is seen at launch Pad-0A, Saturday, May 19, 2018, at Wallops Flight Facility in Virginia. Liftoff is currently targeted for 4:39 a.m. Eastern on Monday, May 21. http://www.nasa.gov/sites/default/files/thumbnails/image/41321485135_0e2afbdc65_o.jpg

The Orbital ATK Antares rocket, with the Cygnus spacecraft onboard, launches from Pad-0A, Monday, May 21, 2018 at NASA's Wallops Flight Facility in Virginia. Cygnus will deliver approximately 7,400 pounds of science and research, crew supplies and vehicle hardware to the International Space Station and its crew. http://www.nasa.gov/sites/default/files/thumbnails/image/42205330652_5f11bfa041_o.jpg