. The Milky Way rises in the sky above the La Silla Paranal Observatory in Chile's Atacama Desert, in an image released May 11 by the European Southern Observatory. The red and greenish-yellow shine is airglow — a faint emission of light by Earth's atmosphere that is usually seen only from space or in very dark locations.
. The Medusa Nebula (also known Abell 21 and Sharpless 2-274) appears in this May 20 picture captured by the European Southern Observatory's Very Large Telescope in Chile. The dying star at the heart of this nebula has shed its outer layers into space, forming this colorful cloud. The image foreshadows the fate of our own sun, billions of years from now.
. NASA astronaut Terry Virts shows off his "penguin suit" on May 12 on the International Space Station. The suit puts compressive force on the wearer's muscles, countering the effects of weightlessness. Astronauts use the penguin suit to prepare their bodies for the return to Earth.
. The Andes Mountains appear in the windows of the Cupola observation deck on the International Space Station, in an image tweeted by NASA astronaut Scott Kelly on May 14.
. Italian astronaut Samantha Cristoforetti tweeted this view of Arizona from the International Space Station on April 29. "What an unreal view!" she wrote.
. A robotic SpaceX Dragon cargo capsule is poised for release from the International Space Station's robotic arm on May 21. This was SpaceX's sixth resupply mission to the space station. The Dragon brought about 3,100 pounds of experimental samples and equipment back down to Earth.
. A Soyuz space capsule is docked to the International Space Station's Rassvet module, as seen in this picture taken by a crew member on April 29. The Russian vehicle had been due to bring NASA astronaut Terry Virts, Italy's Samantha Cristoforetti and Russia's Anton Shkaplerov back home to Earth on May 13. Mission controllers postponed the descent until June, however, due to concerns about the failure of a Russian robotic resupply mission in April.
. An Ariane 5 rocket lifts off from its launch pad in Kourou, French Guiana, carrying DirecTV-15 and Sky Mexico 1 communications satellites on May 27. Europe's Arianespace launch consortium says the DirecTV-15 satellite will provide broadcasts for the continental U.S., Hawaii, Alaska and Puerto Rico, while the Sky Mexico-1 satellite will beam HD broadcasts to Mexico, Central America and the Caribbean.
. NASA astronaut Kjell Lindgren and Japanese astronaut Kimiya Yui take part in a preflight training session on May 7 at Russia's Gagarin Cosmonaut Training Center in Star City, outside Moscow. Lindgren, Yui and Russia's Oleg Kononenko are due to ride a Russian Soyuz capsule to the International Space Station in July.
. NASA's Solar Dynamics Observatory captured this extreme ultraviolet image of an X2.7 solar flare on May 5. The flare, visible as a bright flash on the left edge of the sun's disk, was the most powerful solar outburst so far in 2015.
. Not all galaxies are neatly shaped, as this May 18 image from the Hubble Space Telescope clearly demonstrates. Hubble's science team previously released an image of this galaxy back in 2008, but this more recent picture puts extra emphasis on a central knotted region, shown here in a pinky-red hue. The galaxy NGC 6240 lies 400 million light-years away in the constellation Ophiuchus.
. Saturn seems to exude an aura of serenity and peace in this image from NASA's Cassini orbiter, released on May 11. Despite its serene appearance, Saturn is an active and dynamic world. Its atmosphere is a fast-moving and turbulent place, with wind speeds in excess of 1,100 miles per hour (1,800 kilometers per hour) in places.