Hubble Spots Galaxy’s Dramatic Details

Some of the most dramatic events in the universe occur when certain stars die — and explode catastrophically in the process. When these star deaths, or supernovae, occur, their brightness can rival the light of a whole galaxy. The galaxy NGC 5468, shown in this Hubble image, has hosted a number of these supernovae the past 20 years. via NASA

Pleiades to Hyades

This cosmic vista stretches almost 20 degrees from top to bottom, across the dusty constellation Taurus. It begins at the Pleiades and ends at the Hyades, two star clusters recognized since antiquity in Earth's night sky. At top, the compact Pleiades star cluster is about 400 light-years away. The lovely grouping of young cluster stars shine through dusty clouds that scatter blue starlight. At bottom, the V-shaped Hyades cluster looks more spread out in comparison and lies much closer, 150 light-years away. The Hyades cluster stars seem anchored by bright Aldebaran, a red giant star with a yellowish appearance. But Aldebaran actually lies only 65 light-years distant and just by chance along the line of sight to the Hyades cluster. Faint and darkly obscuring dust clouds found near the edge of the Taurus Molecular Cloud are also evident throughout the celestial scene. The wide field of view includes the dark nebula Barnard 22 at left with youthful star T Tauri and Hind's variable nebula just above Aldebaran in the frame. via NASA

Luca Parmitano Works to Upgrade a Cosmic Particle Detector

European Space Agency astronaut and current International Space Station Commander Luca Parmitano and ​crewmate Andrew Morgan (out of frame) performed the third spacewalk to repair the Alpha Magnetic Spectrometer. via NASA

Spiral Galaxy NGC 6744

Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo and appears as only a faint, extended object in small telescopes. We see the disk of the nearby island universe tilted towards our line of sight in this remarkably detailed galaxy portrait, a telescopic view that spans an area about the angular size of a full moon. In it, the giant galaxy's elongated yellowish core is dominated by the light from old, cool stars. Beyond the core, grand spiral arms are filled with young blue star clusters and speckled with pinkish star forming regions. An extended arm sweeps past a smaller satellite galaxy (NGC 6744A) at the lower right. NGC 6744's galactic companion is reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud. via NASA

Carina Nebula's 'Mystic Mountain'

Within the tempestuous Carina Nebula lies “Mystic Mountain.” via NASA

Electric Night

It may appear, at first, like the Galaxy is producing the lightning, but really it's the Earth. The featured nighttime landscape was taken from a southern tip of the Italian Island of Sardinia in early June. The foreground rocks and shrubs are near the famous Capo Spartivento Lighthouse, and the camera is pointed south toward Algeria in Africa. In the distance, across the Mediterranean Sea, a thunderstorm is threatening, with several electric lightning strokes caught together during this 25-second wide-angle exposure. Much farther in the distance, strewn about the sky, are hundreds of stars in the neighborhood of our Sun in the Milky Way Galaxy. Furthest away, and slanting down from the upper left, are billions of stars that together compose the central band of our Milky Way. via NASA

‘Robot Hotel’ Launching to the International Space Station

Robots need a place to stay in space, too. NASA is attaching a “robot hotel” to the outside of the International Space Station with the upcoming launch of the Robotic Tool Stowage (RiTS). via NASA

M27: The Dumbbell Nebula

Is this what will become of our Sun? Quite possibly. The first hint of our Sun's future was discovered inadvertently in 1764. At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list, now known as M27 or the Dumbbell Nebula, is a planetary nebula, the type of nebula our Sun will produce when nuclear fusion stops in its core. M27 is one of the brightest planetary nebulae on the sky, and can be seen toward the constellation of the Fox (Vulpecula) with binoculars. It takes light about 1000 years to reach us from M27, featured here in colors emitted by hydrogen and oxygen. Understanding the physics and significance of M27 was well beyond 18th century science. Even today, many things remain mysterious about bipolar planetary nebula like M27, including the physical mechanism that expels a low-mass star's gaseous outer-envelope, leaving an X-ray hot white dwarf. via NASA

Mercury Crosses a Quiet Sun

What's that black dot crossing the Sun? The planet Mercury. Mercury usually passes over or under the Sun, as seen from Earth, but last month the Solar System's innermost planet appeared to go just about straight across the middle. Although witnessed by planet admirers across the globe, a particularly clear view was captured by the Solar Dynamics Observatory (SDO) in Earth orbit. The featured video was captured by the SDO's HMI instrument in a broad range of visible light, and compresses the 5 1/2 hour transit into about 13 seconds. The background Sun was unusually quiet -- even for being near Solar Minimum -- and showed no sunspots. The next solar transit by Mercury will occur in 2032. via NASA