Messier Craters in Stereo

Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier, from his famous 18th century catalog. His name is also given to these two large and remarkable craters on the Moon. Standouts in the dark, smooth lunar Sea of Fertility or Mare Fecunditatis, Messier (left) and Messier A have dimensions of 15 by 8 and 16 by 11 kilometers respectively. Their elongated shapes are explained by an extremely shallow-angle trajectory followed by the impactor, moving left to right, that gouged out the craters. The shallow impact also resulted in two bright rays of material extending along the surface to the right, beyond the picture. Intended to be viewed with red/blue glasses (red for the left eye), this striking stereo picture of the crater pair was recently created from high resolution scans of two images (AS11-42-6304, AS11-42-6305) taken during the Apollo 11 mission to the moon. via NASA http://ift.tt/1QgEZs3


Saturn at Opposition

Telescopic observers on Earth have been treated to spectacular views of Saturn lately as the ringed planet reached its 2015 opposition on May 23 at 0200 UT. Of course opposition means opposite the Sun in Earth's sky. So near opposition Saturn is up all night, at its closest and brightest for the year. These sharp images taken within hours of the Sun-Earth-Saturn alignment also show the strong brightening of Saturn's rings known as the opposition surge or the Seeliger Effect. Directly illuminated, the ring's icy particles cast no shadows and strongly backscatter sunlight toward planet Earth, creating the dramatic surge in brightness. Saturn currently stands in the sky not far from bright Antares, alpha star of the constellation Scorpius. via NASA http://ift.tt/1SFDkQR


Hubble Peers into the Most Crowded Place in the Milky Way

This NASA/ESA Hubble Space Telescope image presents the Arches Cluster, the densest known star cluster in the Milky Way. via NASA http://ift.tt/1FHM6qV

Nearby Spiral Galaxy NGC 4945

Large spiral galaxy NGC 4945 is seen edge-on near the center of this cosmic galaxy portrait. In fact, NGC 4945 is almost the size of our own Milky Way Galaxy. Its own dusty disk, young blue star clusters, and pink star forming regions standout in the sharp, colorful telescopic image. About 13 million light-years distant toward the expansive southern constellation Centaurus, NGC 4945 is only about six times farther away than Andromeda, the nearest large spiral galaxy to the Milky Way. Though the galaxy's central region is largely hidden from view for optical telescopes, X-ray and infrared observations indicate significant high energy emission and star formation in the core of NGC 4945. Its obscured but active nucleus qualifies the gorgeous island universe as a Seyfert galaxy and home to a central supermassive black hole. via NASA http://ift.tt/1G1cq2p


Parachute Testing for NASA's InSight Mission

This parachute testing for NASA's InSight mission to Mars was conducted inside the world's largest wind tunnel, at NASA Ames Research Center, Moffett Field, California, in February 2015. via NASA http://ift.tt/1dzEQnH


View From an F-15D

NASA pilot Jim Less and photographer Jim Ross pull their F-15D #897 aircraft away from a KC-135 refueling tanker. NASA is supporting the Edwards Air Force Base F-15 program with safety and photo chase expertise. via NASA http://ift.tt/1AtUvPM

Starburst Galaxy M94

What could cause the center of M94 to be so bright? Spiral galaxy M94 has a ring of newly formed stars surrounding its nucleus, giving it not only an unusual appearance but also a strong interior glow. A leading progenitor hypothesis holds that an elongated knot of stars known as a bar rotates in M94 and has generated a burst of star formation in the inner ring. Recent observations have revealed the outer, fainter ring is not closed and relatively complex. M94, pictured here spans about 30,000 light years, lies about 15 million light years away, and can be seen with a small telescope toward the constellation of the Hunting Dogs (Canes Venatici). via NASA http://ift.tt/1AqAauz


Europa's Jupiter-Facing Hemisphere

This 12-frame mosaic provides the highest resolution view ever obtained of the side of Jupiter's moon Europa that faces the giant planet. It was obtained on Nov. 25, 1999 by the camera onboard the Galileo spacecraft, a past NASA mission to Jupiter and its moons which ended in 2003. via NASA http://ift.tt/1dv2LVx

The Galaxy Tree

First came the trees. In the town of Salamanca, Spain, the photographer noticed how distinctive a grove of oak trees looked after being pruned. Next came the galaxy. The photographer stayed up until 2 am, waiting until the Milky Way Galaxy rose above the level of a majestic looking oak. From this carefully chosen perspective, dust lanes in the galaxy appear to be natural continuations to branches of the tree. Last came the light. A flashlight was used on the far side of the tree to project a silhouette. By coincidence, other trees also appeared as similar silhouettes across the relatively bright horizon. The featured image was captured as a single 30-second frame earlier this month and processed to digitally enhance the Milky Way. via NASA http://ift.tt/1FOKoa8


Space Shuttle Rising

What's that rising from the clouds? The space shuttle. Sometimes, if you looked out the window of an airplane at just the right place and time, you could have seen something very unusual -- a space shuttle launching to orbit. Images of the rising shuttle and its plume became widely circulated over the web shortly after Endeavour's final launch in 2011 May. The above image was taken from a shuttle training aircraft by NASA and is not copyrighted. Taken well above the clouds, the image can be matched with similar images of the same shuttle plume taken below the clouds. Hot glowing gasses expelled by the engines are visible near the rising shuttle, as well as a long smoke plume. A shadow of the plume appears on the cloud deck, indicating the direction of the Sun. The US Space Shuttle program concluded in 2011, and Endeavour can now be visited at the California Science Center. via NASA http://ift.tt/1Q42sgb


NGC 7822 in Cepheus

Hot, young stars and cosmic pillars of gas and dust seem to crowd into NGC 7822. At the edge of a giant molecular cloud toward the northern constellation Cepheus, the glowing star forming region lies about 3,000 light-years away. Within the nebula, bright edges and dark shapes are highlighted in this colorful skyscape. The image includes data from narrowband filters, mapping emission from atomic oxygen, hydrogen, and sulfur into blue, green, and red hues. The atomic emission is powered by energetic radiation from the hot stars, whose powerful winds and radiation also sculpt and erode the denser pillar shapes. Stars could still be forming inside the pillars by gravitational collapse, but as the pillars are eroded away, any forming stars will ultimately be cutoff from their reservoir of star stuff. This field spans around 40 light-years at the estimated distance of NGC 7822. via NASA http://ift.tt/1LvbrpX


A Dark and Dusty Sky

In the dusty sky toward the constellation Taurus and the Orion Arm of our Milky Way Galaxy, this broad mosaic follows dark and faint reflection nebulae along the region's fertile molecular cloud. The six degree wide field of view starts with long dark nebula LDN 1495 stretching from the lower left, and extends beyond the (upside down) bird-like visage of the Baby Eagle Nebula, LBN 777, at lower right. Small bluish reflection nebulae surround scattered fainter Taurus stars, sights often skipped over in favor of the constellation's better known, brighter celestial spectacles. Associated with the young, variable star RY Tau, the yellowish nebula VdB 27 is toward the upper left. Only 400 light-years or so distant, the Taurus molecular cloud is one of the closest regions of low-mass star formation. At that distance this dark vista would span over 40 light-years. via NASA http://ift.tt/1K7yTsl


Coronal Loops Over a Sunspot Group

The Atmospheric Imaging Assembly (AIA) instrument on NASA's Solar Dynamics Observatory images the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes. When AIA images are sharpened a bit, such as this AIA 171Å channel image, the magnetic field can be readily visualized through the bright, thin strands that ar via NASA http://ift.tt/1Q1m9oI

NGC 6240: Merging Galaxies

NGC 6240 offers a rare, nearby glimpse of a cosmic catastrophe in its final throes. The titanic galaxy-galaxy collision takes place a mere 400 million light-years away in the constellation Ophiuchus. The merging galaxies spew distorted tidal tails of stars, gas, and dust and undergo fast and furious bursts of star formation. The two supermassive black holes in the original galactic cores will also coalesce into a single, even more massive black hole and soon, only one large galaxy will remain. This dramatic image of the scene is a composite of narrowband and near-infrared to visible broadband data from Hubble's ACS and WPC3 cameras, a view that spans over 300,000 light-years at the estimated distance of NGC 6240. via NASA http://ift.tt/1FyeyfY


SpinSat Investigation Tests New Technology, Returns Data

Equipment and data from the SpinSat investigation returns to Earth today, May 21, 2015, with splashdown of the sixth SpaceX cargo resupply mission to the International Space Station. This Nov. 28, 2014 photograph by NASA astronaut Terry Virts captures the predeploy of SpinSat, which was launched into orbit from the station. via NASA http://ift.tt/1KmpTCL


The Advance of Hubbard Glacier

This image, acquired by the Operational Land Imager (OLI) on Landsat 8, shows Hubbard Glacier on July 22, 2014. via NASA http://ift.tt/1FvZ9wP


Journey to Space in a Vacuum Chamber

Supporting the testing of electric propulsion and power systems, VF-5 has the highest pumping speed of any electric propulsion test facility in the world. via NASA http://ift.tt/1S6QzK1

Auroras and Star Trails over Iceland

It was one of the quietest nights of aurora in weeks. Even so, in northern- Iceland during last November, faint auroras lit up the sky every clear night. The featured 360-degree panorama is the digital fusion of four wide-angle cameras each simultaneously taking 101 shots over 42 minutes. In the foreground is serene Lake Myvatn dotted with picturesque rock formations left over from ancient lava flows. Low green auroras sweep across the sky above showing impressive complexity near the horizon. Stars far in the distance appear to show unusual trails -- as the Earth turned -- because early exposures were artificially faded. via NASA http://ift.tt/1ERQm3t


Mount St. Helens at 35

On May 18, 1980, Mount St. Helens gave way to a cataclysmic flank collapse, avalanche, and explosion that killed 57 people and displaced many others. The event dramatically reshaped the volcano and surrounding land in southwest Washington. via NASA http://ift.tt/1df1mlF

NGC 2440: Pearl of a New White Dwarf

Like a pearl, a white dwarf star shines best after being freed from its shell. In this analogy, however, the Sun would be a mollusk and its discarded hull would shine prettiest of all! In the above shell of gas and dust, the planetary nebula designated NGC 2440, contains one of the hottest white dwarf stars known. The glowing stellar pearl can be seen as the bright dot near the image center. The portion of NGC 2440 shown spans about one light year. The center of our Sun will eventually become a white dwarf, but not for another five billion years. The above false color image was captured by the Hubble Space Telescope in 1995. NGC 2440 lies about 4,000 light years distant toward the southern constellation Puppis. via NASA http://ift.tt/1PNOVt1


Ares 3 Landing Site: The Martian Revisited

This close-up from the Mars Reconnaissance Orbiter's HiRISE camera shows weathered craters and windblown deposits in southern Acidalia Planitia. A striking shade of blue in standard HiRISE image colors, to the human eye the area would probably look grey or a little reddish. But human eyes have not gazed across this terrain, unless you count the eyes of NASA astronauts in the scifi novel The Martian by Andy Weir. The novel chronicles the adventures of Mark Watney, an astronaut stranded at the fictional Mars mission Ares 3 landing site corresponding to the coordinates of this cropped HiRISE frame. For scale Watney's 6-meter-diameter habitat at the site would be about 1/10th the diameter of the large crater. Of course, the Ares 3 landing coordinates are only about 800 kilometers north of the (real life) Carl Sagan Memorial Station, the 1997 Pathfinder landing site. via NASA http://ift.tt/1IDwRmz


Jupiter, Ganymede, Great Red Spot

In this sharp snapshot, the Solar System's largest moon Ganymede poses next to Jupiter, the largest planet. Captured on March 10 with a small telescope from our fair planet Earth, the scene also includes Jupiter's Great Red Spot, the Solar System's largest storm. In fact, Ganymede is about 5,260 kilometers in diameter. That beats out all three of its other fellow Galilean satellites, along with Saturn's Moon Titan at 5,150 kilometers and Earth's own Moon at 3,480 kilometers. Though its been shrinking lately, the Great Red Spot's diameter is still around 16,500 kilometers. Jupiter, the Solar System's ruling gas giant, is about 143,000 kilometers in diameter at its equator. That's nearly 10 percent the diameter of the Sun. via NASA http://ift.tt/1KQ6A1D


Astronauts at Work on the International Space Station

NASA astronauts Scott Kelly (left) and Terry Virts (right) work on a Carbon Dioxide Removal Assembly (CDRA) inside the station's Japanese Experiment Module. via NASA http://ift.tt/1RPB752

Dwarf Planet, Bright Spot

Now at Ceres, Dawn's camera recorded this closer view of the dwarf planet's northern hemisphere and one of its mysterious bright spots on May 4. A sunlit portrait of a small, dark world about 950 kilometers in diameter, the image is part of a planned sequence taken from the solar-powered spacecraft's 15-day long RC3 mapping orbit at a distance of 13,600 kilometers (8,400 miles). The animated sequence shows Ceres' rotation, its north pole at the top of the frame. Imaged by Hubble in 2004 and then by Dawn as it approached Ceres in 2015, the bright spot itself is revealed to be made up of smaller spots of reflective material that could be exposed ice glinting in the sunlight. On Saturday, Dawn's ion propulsion system was turned on to spiral the spacecraft into a closer 4,350-kilometer orbit by June 6. Of course another unexplored dwarf planet, Pluto, is expecting the arrival of a visitor from Earth, the New Horizons spacecraft, by mid-July. via NASA http://ift.tt/1Izrjt8


Green Aviation Project Tests Shape Changing Wing Flaps

A NASA F-15D flies chase for the G-III Adaptive Compliant Trailing Edge (ACTE) project. The ACTE experimental flight research project is a joint effort between NASA and the U.S. Air Force Research Laboratory to determine if advanced flexible trailing-edge wing flaps can both improve aircraft aerodynamic efficiency and reduce airport-area noise. via NASA http://ift.tt/1AZlddP

The Magnificent Horsehead Nebula

Sculpted by stellar winds and radiation, a magnificent interstellar dust cloud by chance has assumed this recognizable shape. Fittingly named the Horsehead Nebula, it is some 1,500 light-years distant, embedded in the vast Orion cloud complex. About five light-years "tall", the dark cloud is cataloged as Barnard 33 and is visible only because its obscuring dust is silhouetted against the glowing red emission nebula IC 434. Stars are forming within the dark cloud. Contrasting blue reflection nebula NGC 2023, surrounding a hot, young star, is at the lower left. The gorgeous featured image combines both narrowband and broadband images. via NASA http://ift.tt/1G54ZFU


May 13, 1992, Record-Setting Spacewalk on Shuttle Endeavour's First Mission

On May 13, 1992, following the successful capture of the Intelsat VI satellite, three astronauts continue moving the 4.5 ton communications satellite into the space shuttle Endeavour's cargo bay. The sections of Earth which form the backdrop for the scene are blanketed with thousands of square miles of clouds. via NASA http://ift.tt/1F7sPi5

Two Worlds One Sun

How different does sunset appear from Mars than from Earth? For comparison, two images of our common star were taken at sunset, one from Earth and one from Mars. These images were scaled to have same angular width and featured here side-by-side. A quick inspection will reveal that the Sun appears slightly smaller from Mars than from Earth. This makes sense since Mars is 50% further from the Sun than Earth. More striking, perhaps, is that the Martian sunset is noticeably bluer near the Sun than the typically orange colors near the setting Sun from Earth. The reason for the blue hues from Mars is not fully understood, but thought to be related to forward scattering properties of Martian dust. The terrestrial sunset was taken in 2012 March from Marseille, France, while the Martian sunset was captured last month by NASA's robotic Curiosity rover from Gale crater on Mars. via NASA http://ift.tt/1E34PJg


Early Morning Sunrise Over the Grand Canyon

From the International Space Station, NASA astronaut Terry Virts took this photograph of an early morning sunrise over the Grand Canyon and posted it to social media on May 10, 2015. Because the station completes each trip around the globe in about 92 minutes, the crew experiences 16 sunrises and sunsets each day. via NASA http://ift.tt/1K4phBN

The Sky from Mauna Kea

What if you could stand at the top of a volcano and peer out across the universe? If the timing is right, you might see an amazing panorama like the one featured here. In this case, the volcano is the Hawaii's Mauna Kea, and the time was a clear night last summer In the foreground of this south-facing panorama lies a rugged landscape dotted with rocks and hardy plants. Slightly above and further out, a white blanket of clouds spreads horizontally to the horizon, seemingly dividing heaven and Earth. City lights illuminate the clouds and sky on the far left, while orange lava in the volcanic caldera of Kilauea lights up the clouds just left of center. The summit of an even more distant Hawaiian volcano, Mauna Loa, is visible in dark silhouette near the central horizon. Green airglow is visible above the clouds, caused by air molecules excited by the Sun during the day. The Moon is the bright orb on the right. A diffuse band of light-colored zodiacal light extends up from the far right. Most distant, the dramatic central band of our Milky Way Galaxy appears to rise vertically from Mauna Loa. The person who witnessed and captured this breathtaking panorama stands before you in the image center. via NASA http://ift.tt/1cGN4Kj


Serene Saturn

From a distance Saturn seems to exude an aura of serenity and peace. via NASA http://ift.tt/1E23G4D

MyCn18: An Hourglass Planetary Nebula

The sands of time are running out for the central star of this hourglass-shaped planetary nebula. With its nuclear fuel exhausted, this brief, spectacular, closing phase of a Sun-like star's life occurs as its outer layers are ejected - its core becoming a cooling, fading white dwarf. In 1995, astronomers used the Hubble Space Telescope (HST) to make a series of images of planetary nebulae, including the one above. Here, delicate rings of colorful glowing gas (nitrogen-red, hydrogen-green, and oxygen-blue) outline the tenuous walls of the hourglass. The unprecedented sharpness of the HST images has revealed surprising details of the nebula ejection process that are helping to resolve the outstanding mysteries of the complex shapes and symmetries of planetary nebulas. via NASA http://ift.tt/1EnPsMR


Trio Leo

This popular group is famous as the Leo Triplet - a gathering of three magnificent galaxies in one field of view. Crowd pleasers when imaged with even modest telescopes, they can be introduced individually as NGC 3628 (left), M66 (bottom right), and M65 (top). All three are large spiral galaxies but they tend to look dissimilar because their galactic disks are tilted at different angles to our line of sight. NGC 3628 is seen edge-on, with obscuring dust lanes cutting across the plane of the galaxy, while the disks of M66 and M65 are both inclined enough to show off their spiral structure. Gravitational interactions between galaxies in the group have also left telltale signs, including the warped and inflated disk of NGC 3628 and the drawn out spiral arms of M66. This gorgeous view of the region spans about one degree (two full moons) on the sky. The field covers over 500 thousand light-years at the trio's estimated distance of 30 million light-years. via NASA http://ift.tt/1cxTw6n


When Vega is North

In only about 12,000 years Vega will be the North Star, the closest bright star to our fair planet's North Celestial Pole. By then, when you fix your camera to a tripod long exposures of the night sky will show the concentric arcs of star trails centered on a point near Vega as Earth rotates on its axis. Of course, presently the bright star conveniently near the North Celestial Pole is Polaris, but that will change as the Earth's axis of rotation precesses, like the wobble of a spinning top with a precession period of about 26,000 years. If your camera is ready now and you don't want to wait 12,000 years for Vega to be the North Star, consider this ingenious demonstration of contemporary star trails (left) versus star trails reminiscent of the year 14000 CE. Both were recorded this April at the Alqueva Dark Sky Reserve in Alentejo, Portugal. To produce the more Vega-centric star trails of the distant future, astronomer Miguel Claro combined the rotation of two startracking camera mounts to create the apparent shift in the North Celestial Pole. (Addendum: Thanks to APOD readers who note that when Vega is the North Star it will also appear near the same position that Polaris is now relative to the landscape.) via NASA http://ift.tt/1IlqaFp


Cloudy Earth

Earth’s cloudy nature is unmistakable in this global cloud fraction map, based on data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite. This version of the map shows an average of all of the satellite’s cloud observations between July 2002 and April 2015. via NASA http://ift.tt/1cfuCI7

At the Limit of Diffraction

Did you ever want to just look through the eyepiece of a large telescope in space? If you could, you would see a sharp view that was diffraction limited. Unaffected by atmospheric blurring that ultimately plagues earthbound observers, the angular resolution of your diffraction limited view would be determined only by the wavelength of light and diameter of the telescope lens or mirror; the larger the diameter, the sharper the image. Still, in this working earth-based snapshot a new active adaptive optics system (MagAO) is being used to cancel out the atmospheric blurring in a visual observation of famous double star system Alpha Centauri. Testing the system at the eyepiece of the 6.5 meter diameter Magellan Clay Telescope at Las Campanas Observatory, astronomer Laird Close is enjoying a historic diffraction limited view (inset) and the wide apparent separation of the close binary star system ... without traveling to low earth orbit. via NASA http://ift.tt/1DToCL5


Engineers Clean Mirror with Carbon Dioxide Snow

Engineers are using carbon dioxide snow to clean James Webb Space Telescope's mirrors without scratching them. via NASA http://ift.tt/1EkcF1x

Summer Triangles over Japan

Have you ever seen the Summer Triangle? The bright stars Vega, Deneb, and Altair form a large triangle on the sky that can be seen rising in the early northern early spring during the morning and rising in the northern fall during the evening. During summer months, the triangle can be found nearly overhead near midnight. Featured here, the Summer Triangle asterism was captured last month from Gunma, Japan. In the foreground, sporting a triangular shape of its own, is a flowering 500 year old cherry tree, standing about 15 meters tall. The triangular shape of the asterism is only evident from the direction of Earth -- in actuality the stars are thousands of light years apart in space. via NASA http://ift.tt/1EfbIr9


Solar Dynamics Observatory Sees 'Cinco de Mayo' Solar Flare

NASA's Solar Dynamics Observatory, which watches the sun constantly, captured these images of a significant solar flare – as seen in the bright flash on the left – peaking at 6:11 p.m. EDT on May 5, 2015. Each image shows a different wavelength of extreme ultraviolet light that highlights a different temperature of material on the sun. via NASA http://ift.tt/1KLRniC

Gravitational Anomalies of Mercury

What's that under the surface of Mercury? The robotic MESSENGER spacecraft that had been orbiting planet Mercury for the past four years had been transmitting its data back to Earth with radio waves of very precise energy. The planet's gravity, however, slightly changed this energy when measured on Earth, which enabled the reconstruction of a gravity map of unprecedented precision. Here gravitational anomalies are shown in false-color, superposed on an image of the planet's cratered surface. Red hues indicate areas of slightly higher gravity, which in turn indicates areas that must have unusually dense matter under the surface. The central area is Caloris Basin, a huge impact feature measuring about 1,500 kilometers across. Last week, after completing its mission and running low on fuel, MESSENGER was purposely crashed onto Mercury's surface. via NASA http://ift.tt/1GWOcDn


Trajectory of Alan Shepard's Historic Flight

Fifty-four years ago on May 5, 1961 only 23 day after Yuri Gagarin of the then-Soviet Union became the first person in space, NASA astronaut Alan Shepard launched at 9:34 a.m. EDT aboard his Freedom 7 capsule powered by a Redstone booster to become the first American in space. His historic flight lasted 15 minutes, 28 seconds. via NASA http://ift.tt/1FMOPRm

An Unexpected Aurora over Norway

Sometimes the sky lights up unexpectedly. A trip to northern Norway to photograph auroras was not going as well as hoped. It was now past midnight in Steinsvik, Troms, in northern Norway, and the date was 2014 February 8. Despite recent activity on the Sun, the skies were disappointing. Therefore, the astrophotographer began packing up to go. His brother began searching for a missing lens cap. When the sky suddenly exploded with spectacular aurora. Reacting quickly, a sequence detailing dramatic green curtains was captured, with the bright Moon near the image center, and the lens-cap seeking brother on the far right. The auroral flare lasted only a few minutes, but the memory of this event, the photographer speculates, will last much longer. via NASA http://ift.tt/1KFXrt3


Mimas Stares Back

The great eye of Saturn's moon Mimas, a 130-kilometer-wide (80-mile) impact crater called Herschel, stares out from the battered moon. Several individual ringlets within the F ring are resolved here, and the small moon Atlas is also seen faintly outside the main rings. via NASA http://ift.tt/1E0rtTI

Moonrise Through Mauna Keas Shadow

How can the Moon rise through a mountain? It cannot -- what was photographed here is a moonrise through the shadow of a large volcano. The volcano is Mauna Kea, Hawai'i, USA, a frequent spot for spectacular photographs since it is arguably the premier observing location on planet Earth. The Sun has just set in the opposite direction, behind the camera. Additionally, the Moon has just passed full phase -- were it precisely at full phase it would rise, possibly eclipsed, at the very peak of the shadow. The Moon is actually rising in the triangular shadow cone of the volcano, a corridor of darkness that tapers off in the distance like converging train tracks. The Moon is too large and too far away to be affected by the shadow of the volcano. Refraction of moonlight through the Earth's atmosphere makes the Moon appear slightly oval. Cinder cones from old volcanic eruptions are visible in the foreground. via NASA http://ift.tt/1EN8EHk


M51: The Whirlpool Galaxy

Follow the handle of the Big Dipper away from the dipper's bowl until you get to the handle's last bright star. Then, just slide your telescope a little south and west and you might find this stunning pair of interacting galaxies, the 51st entry in Charles Messier famous catalog. Perhaps the original spiral nebula, the large galaxy with well defined spiral structure is also cataloged as NGC 5194. Its spiral arms and dust lanes clearly sweep in front of its companion galaxy (right), NGC 5195. The pair are about 31 million light-years distant and officially lie within the angular boundaries of the small constellation Canes Venatici. Though M51 looks faint and fuzzy to the eye, deep images like this one can reveal striking colors and the faint tidal debris around the smaller galaxy via NASA http://ift.tt/1I0dxhi


MESSENGER's Last Day on Mercury

The first to orbit Mercury, the MESSENGER spacecraft came to rest on this region of Mercury's surface yesterday. Constructed from MESSENGER image and laser altimeter data, the scene looks north over the northeastern rim of the broad, lava filled Shakespeare basin. The large, 48 kilometer (30 mile) wide crater Janacek is near the upper left edge. Terrain height is color coded with red regions about 3 kilometers above blue ones. MESSENGER'S final orbit was predicted to end near the center, with the spacecraft impacting the surface at nearly 4 kilometers per second (over 8,700 miles per hour) and creating a new crater about 16 meters (52 feet) in diameter. The impact on the far side of Mercury was not observed by telescopes, but confirmed when no signal was detected from the spacecraft given time to emerge from behind the planet. Launched in 2004, the MErcury Surface, Space ENvironment, GEochemisty and Ranging spacecraft completed over 4,000 orbits after reaching the Solar System's innermost planet in 2011. via NASA http://ift.tt/1EygYcP


Ten-Engine Electric Plane Prototype Takes Off

A team at NASA's Langley Research Center is developing a concept of a battery-powered plane that has 10 engines and can take off like a helicopter and fly efficiently like an aircraft. The prototype, called Greased Lightning or GL-10, is currently in the design and testing phase. via NASA http://ift.tt/1QU3iz8

Across the Sun

A long solar filament stretches across the relatively calm surface of the Sun in this telescopic snap shot from April 27. The negative or inverted narrowband image was made in the light of ionized hydrogen atoms. Seen at the upper left, the magnificent curtain of magnetized plasma towers above surface and actually reaches beyond the Sun's edge. How long is the solar filament? About as long as the distance from Earth to Moon, illustrated by the scale insert at the left. Tracking toward the right across the solar disk a day later the long filament erupted, lifting away from the Sun's surface. Monitored by Sun staring satellites, a coronal mass ejection was also blasted from the site but is expected to swing wide of our fair planet. via NASA http://ift.tt/1zs3mAW