Solstice Sun at Lulworth Cove

A southern exposure and striking symmetry made Lulworth Cove, along the Jurassic Coast of England, planet Earth a beautiful setting during December's Solstice. Five frames in this dramatic composite view follow the lowest arc of the Sun, from sunrise to sunset, during the shortest day of the year. The solstice arc spans about 103 degrees at this northern latitude. Of course, erosion by wave action has produced the cove's remarkable shape in the coastal limestone layers. The cove's narrow entrance is responsible, creating a circular wave diffraction pattern. The wave pattern is made clearer by the low solstice Sun. via NASA http://ift.tt/1OuqcZp

The Fox Fur Nebula

This interstellar canine is formed of cosmic dust and gas interacting with the energetic light and winds from hot young stars. The shape, visual texture, and color, combine to give the region the popular name Fox Fur Nebula. The characteristic blue glow on the left is dust reflecting light from the bright star S Mon, the bright star just below the top edge of the featured image. Textured red and black areas are a combination of the cosmic dust and reddish emission from ionized hydrogen gas. S Mon is part of a young open cluster of stars, NGC 2264, located about 2,500 light years away toward the constellation of the Unicorn (Monoceros). via NASA http://ift.tt/1RRhE5q

Dust of the Orion Nebula

What surrounds a hotbed of star formation? In the case of the Orion Nebula -- dust. The entire Orion field, located about 1600 light years away, is inundated with intricate and picturesque filaments of dust. Opaque to visible light, dust is created in the outer atmosphere of massive cool stars and expelled by a strong outer wind of particles. The Trapezium and other forming star clusters are embedded in the nebula. The intricate filaments of dust surrounding M42 and M43 appear brown in the featured image, while central glowing gas is highlighted in red. Over the next few million years much of Orion's dust will be slowly destroyed by the very stars now being formed, or dispersed into the Galaxy. via NASA http://ift.tt/1PuLd9H

Doomed Star Eta Carinae

Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova. Historical records do show that about 150 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky. Eta Carinae, in the Keyhole Nebula, is the only star currently thought to emit natural LASER light. This featured image, taken in 1996, brought out new details in the unusual nebula that surrounds this rogue star. Now clearly visible are two distinct lobes, a hot central region, and strange radial streaks. The lobes are filled with lanes of gas and dust which absorb the blue and ultraviolet light emitted near the center. The streaks remain unexplained. via NASA http://ift.tt/1On0iH4

Southern Craters and Galaxies

The Henbury craters in the Northern Territory, Australia, planet Earth, are the scars of an impact over 4,000 years old. When an ancient meteorite fragmented into dozens of pieces, the largest made the 180 meter diameter crater whose weathered walls and floor are lit in the foreground of this southern hemisphere nightscape. The vertical panoramic view follows our magnificent Milky Way galaxy stretching above horizon, its rich central starfields cut by obscuring dust clouds. A glance along the galactic plane also reveals Alpha and Beta Centauri and the stars of the Southern Cross. Captured in the region's spectacular, dark skies, the Small Magellanic Cloud, satellite of the Milky Way, is the bright galaxy to the left. Not the lights of a nearby town, the visible glow on the horizon below it is the Large Magellanic Cloud rising. via NASA http://ift.tt/1OrZQgI

Star Colors and Pinyon Pine

Beautiful, luminous decorations on this pinyon pine tree are actually bright stars in the constellation Scorpius and the faint glow of the central Milky Way. Captured in June from the north rim of the Grand Canyon of planet Earth, the shallow, close focus image has rendered pine needles on the tree branch sharp, but blurred the distant stars, their light smeared into remarkably colorful disks. Of course, temperature determines the color of a star. Most of the out-of-focus bright stars of Scorpius show a predominately blue hue, their surface temperatures much hotter than the Sun's. Cooler and larger than the Sun, and noticably redder on the scene, is giant star Antares at the heart of the scorpion. In focused, telescopic views the whitish disk at the upper right would be immediately recognizable though, reflecting the Sun's light as ringed gas giant Saturn. via NASA http://ift.tt/1OpIO30

Geminid Meteors over Xinglong Observatory

Where do Geminid meteors come from? In terms of location on the sky, as the featured image composite beautifully demonstrates, the sand-sized bits of rock that create the streaks of the Geminid Meteor Shower appear to flow out from the constellation of Gemini. In terms of parent body, Solar System trajectories point to the asteroid 3200 Phaethon -- but this results in a bit of a mystery since that unusual object appears mostly dormant. Perhaps, 3200 Phaethon undergoes greater dust-liberating events than we know, but even if so, exactly what happens and why remains a riddle. Peaking last week, over 50 meteors including a bright fireball were captured streaking above Xinglong Observatory in China. Since the Geminids of December are one of the most predictable and active meteor showers, investigations into details of its origin are likely to continue. via NASA http://ift.tt/1RGdL3e

SN Refsdal: The First Predicted Supernova Image

It's back. Never before has an observed supernova been predicted. The unique astronomical event occurred in the field of galaxy cluster MACS J1149.5+2223. Most bright spots in the featured image are galaxies in this cluster. The actual supernova, dubbed Supernova Refsdal, occurred just once far across the universe and well behind this massive galaxy cluster. Gravity caused the cluster to act as a massive gravitational lens, splitting the image of Supernova Refsdal into multiple bright images. One of these images arrived at Earth about ten years ago, likely in the upper red circle, and was missed. Four more bright images peaked in April in the lowest red circle, spread around a massive galaxy in the cluster as the first Einstein Cross supernova. But there was more. Analyses revealed that a sixth bright supernova image was likely still on its way to Earth and likely to arrive within the next year. Earlier this month -- right on schedule -- this sixth bright image was recovered, in the middle red circle, as predicted. Studying image sequences like this help humanity to understand how matter is distributed in galaxies and clusters, how fast the universe expands, and how massive stars explode. via NASA http://ift.tt/1NItoRO

A Dark Earth with a Red Sprite

There is something very unusual in this picture of the Earth -- can you find it? A fleeting phenomenon once thought to be only a legend has been newly caught if you know just where to look. The featured image was taken from the orbiting International Space Station (ISS) in late April and shows familiar ISS solar panels on the far left and part of a robotic arm to the far right. The rarely imaged phenomenon is known as a red sprite and it can be seen, albeit faintly, just over the bright area on the image right. This bright area and the red sprite are different types of lightning, with the white flash the more typical type. Although sprites have been reported anecdotally for as long as 300 years, they were first caught on film in 1989 -- by accident. Much remains unknown about sprites including how they occur, their effect on the atmospheric global electric circuit, and if they are somehow related to other upper atmospheric lightning phenomena such as blue jets or terrestrial gamma flashes. via NASA http://ift.tt/1JlE0Eh

Star Streams and the Whale Galaxy

NGC 4631 is a spiral galaxy found only 25 million light-years away, toward the well-trained northern constellation Canes Venatici. Seen ege-on, the galaxy is similar in size to the Milky Way. Its distorted wedge shape suggests to some a cosmic herring and to others its popular moniker, The Whale Galaxy. The large galaxy's small, remarkably bright elliptical companion NGC 4627 lies just above its dusty yellowish core, but also identifiable are recently discovered, faint dwarf galaxies within the halo of NGC 4631. In fact, the faint extended features below (and above) NGC 4631 are now recognized as tidal star streams. The star streams are remnants of a dwarf satellite galaxy disrupted by repeated encounters with the Whale that began about 3.5 billion years ago. Even in nearby galaxies, the presence of tidal star streams is predicted by cosmological models of galaxy formation, including the formation of our own Milky Way. via NASA http://ift.tt/1YnMMh7

Herbig Haro 24

This might look like a double-bladed lightsaber, but these two cosmic jets actually beam outward from a newborn star in a galaxy near you. Constructed from Hubble Space Telescope image data, the stunning scene spans about half a light-year across Herbig-Haro 24 (HH 24), some 1,300 light-years or 400 parsecs away in the stellar nurseries of the Orion B molecular cloud complex. Hidden from direct view, HH 24's central protostar is surrounded by cold dust and gas flattened into a rotating accretion disk. As material from the disk falls toward the young stellar object it heats up. Opposing jets are blasted out along the system's rotation axis. Cutting through the region's interstellar matter, the narrow, energetic jets produce a series of glowing shock fronts along their path. via NASA http://ift.tt/1k6olSs

Geminids of the South

Earth's annual Geminid meteor shower did not disappoint, peaking before dawn on December 14 as our fair planet plowed through dust from active asteroid 3200 Phaethon. Captured in this southern hemisphere nightscape the meteors stream away from the shower's radiant in Gemini. To create the image, many individual frames recording meteor streaks were taken over period of 5 hours. In the final composite they were selected and registered against the starry sky above the twin 6.5 meter Magellan telescopes of Carnegie Las Campanas Observatory in Chile. Rigel in Orion, and Sirius shine brightly as the Milky Way stretches toward the zenith. Near Castor and Pollux the twin stars of Gemini, the meteor shower's radiant is low, close to the horizon. The radiant effect is due to perspective as the parallel meteor tracks appear to converge in the distance. Gemini's meteors enter Earth's atmosphere traveling at about 22 kilometers per second. via NASA http://ift.tt/22acbu1

The Horsehead Nebula

The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the red emission nebula in the center of the above photograph. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright red emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will surely alter its appearance. The emission nebula's red color is caused by electrons recombining with protons to form hydrogen atoms. On the image left is the Flame Nebula, an orange-tinged nebula that also contains filaments of dark dust. Just to the lower left of the Horsehead nebula featured picture is a blueish reflection nebulae that preferentially reflects the blue light from nearby stars. via NASA http://ift.tt/1lPuhBd

Colorful Arcs over Buenos Aires

What are those colorful arcs in the sky? Like rainbows that are caused by rain, arcs of sunlight broken up into component colors can also result when ice crystals floating in Earth's atmosphere act together as a gigantic prism. The top color arc is more typical as it is part of the 22 degree halo surrounding the Sun when hexagonal ice crystals refract sunlight between two of the six sides. More unusual, though, is the bottom color arc. Sometimes called a fire rainbow, this circumhorizon arc is also created by ice, not fire nor even rain. Here, a series of horizontal, thin, flat ice crystals in high cirrus clouds refract sunlight between the top and bottom faces toward the observer. These arcs only occur when the Sun is higher than 58 degrees above the horizon. The featured sky occurred to the northwest in the early afternoon last month over a street Diagonal of La Plata City, Buenos Aires, Argentina. via NASA http://ift.tt/1J92mRy

Pluto: From Mountains to Plains

What do the sharpest views ever of Pluto show? As the robotic New Horizons spacecraft moves into the outer Solar System, it is now sending back some of the highest resolution images from its historic encounter with Pluto in July. Featured here is one recently-received, high-resolution image. On the left is al-Idrisi Montes, mountainous highlands thought composed primarily of blocks of water ice. A sharp transitional shoreline leads to the ice plains, on the right, that compose part of the heart-shaped feature known as Sputnik Planum, which contains ices including solid nitrogen. Why the plains are textured with ice pits and segmented is currently unknown. The image was taken about 15 minutes before closest approach and shows an area about 30 kilometers across. The New Horizons spacecraft is next scheduled to fly past Kuiper Belt object 2014 MU 69 on New Year's Day 2019. via NASA http://ift.tt/1I3Z5b6

When Gemini Sends Stars to Paranal

From a radiant point in the constellation of the Twins, the annual Geminid meteor shower rain down on planet Earth. Tonight, the Geminds reach their peak and could be quite spectacular. The featured blended image, however, captured the shower's impressive peak in the year 2012. The beautiful skyscape collected Gemini's lovely shooting stars in a careful composite of 30 exposures, each 20 seconds long, from the dark of the Chilean Atacama Desert over ESO's Paranal Observatory. In the foreground Paranal's four Very Large Telescopes, four Auxillary Telescopes, and the VLT Survey telescope are all open and observing. The skies above are shared with bright Jupiter (left), Orion, (top left), and the faint light of the Milky Way. Dust swept up from the orbit of active asteroid 3200 Phaethon, Gemini's meteors enter Earth's atmosphere traveling at about 22 kilometers per second. via NASA http://ift.tt/1Z6nQYq

Comet Meets Moon and Morning Star

A crescent Moon and brilliant Venus met in predawn skies on December 7, a beautiful conjunction of planet Earth's two brightest celestial beacons after the Sun. Harder to see but also on the scene was Comet Catalina (C/2013 US10). The fainter comet clearly sporting two tails, lunar night side, bright sunlit lunar crescent, and brilliant morning star, are all recorded here by combining short and long exposures of the same field of view. Pointing down and right, Catalina's dust tail tends to trail behind the comet's orbit. Its ion tail, angled toward the top left of the frame, is blowing away from the Sun. Discovered in 2013, the new visitor from the Oort cloud was closest to the Sun on November 15 and is now outbound, headed for its closest approach to Earth in mid-January. via NASA http://ift.tt/1NoBxug

The Brightest Spot on Ceres

Dwarf planet Ceres is the largest object in the Solar System's main asteroid belt with a diameter of about 950 kilometers. Exploring Ceres from orbit since March, the Dawn spacecraft's camera has revealed about 130 or so mysterious bright spots, mostly associated with impact craters scattered around the small world's otherwise dark surface. The brightest one is near the center of the 90 kilometer wide Occator Crater, seen in this dramatic false color view combining near-infrared and visible light image data. A study now finds the bright spot's reflected light properties are probably most consistent with a type of magnesium sulfate called hexahydrite. Of course, magnesium sulfate is also known to Earth dwellers as epsom salt. Haze reported inside Occator also suggests the salty material could be left over as a mix of salt and water-ice sublimates on the surface. Since impacts would have exposed the material, Ceres' numerous and widely scattered bright spots may indicate the presence of a subsurface shell of ice-salt mix. In mid-December, Dawn will begin taking observations from its closest Ceres mapping orbit. via NASA http://ift.tt/1Y1YXjt

Daytime Moon Meets Morning Star

Venus now appears as Earth's brilliant morning star, standing in a line-up of planets above the southeastern horizon before dawn. For most, the silvery celestial beacon rose predawn in a close pairing with an old crescent Moon on Monday, December 7. But also widely seen from locations in North and Central America, the lunar crescent actually occulted or passed in front of Venus during Monday's daylight hours. This time series follows the daytime approach of Moon and morning star in clear blue skies from Phoenix, Arizona. The progression of nine sharp telescopic snapshots, made between 9:30am and 9:35am local time, runs from lower left to upper right, when Venus winked out behind the bright lunar limb. via NASA http://ift.tt/1jQd6NP

Arp 87: Merging Galaxies from Hubble

This dance is to the death. Along the way, as these two large galaxies duel, a cosmic bridge of stars, gas, and dust currently stretches over 75,000 light-years and joins them. The bridge itself is strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity. As further evidence, the face-on spiral galaxy on the right, also known as NGC 3808A, exhibits many young blue star clusters produced in a burst of star formation. The twisted edge-on spiral on the left (NGC 3808B) seems to be wrapped in the material bridging the galaxies and surrounded by a curious polar ring. Together, the system is known as Arp 87 and morphologically classified, technically, as peculiar. While such interactions are drawn out over billions of years, repeated close passages should ultimately result in the death of one galaxy in the sense that only one galaxy will eventually result. Although this scenario does look peculiar, galactic mergers are thought to be common, with Arp 87 representing a stage in this inevitable process. The Arp 87 pair are about 300 million light-years distant toward the constellation Leo. The prominent edge-on spiral at the far left appears to be a more distant background galaxy and not involved in the on-going merger. via NASA http://ift.tt/1NifXrv

Icelandic Legends and Aurora

Legends collide in this dramatic vista of land, sea, and sky. The land is Iceland, specifically Vík í Mýrdal, a southern village known for its beautiful black sand beaches. The sea, the Atlantic Ocean, surrounds Reynisdrangar, a sea stack of eroded basaltic rock pillars that Icelandic folklore tells are the petrified remains of trolls once attempting to drag a three-masted ship onto land. Watching from overhead and shining bright on the upper right is the god of the sky, according to Greek mythology: the planet Jupiter. Also visible in the sky are several other Greek legends encapsulated as constellations, including a lion (Leo), a big bear (Ursa Major), and a water snake (Hydra). One might guess that all of this commotion caused the spectacular aurora pictured -- but really it was just explosions from the Sun. via NASA http://ift.tt/1TXUTuT

Comet Catalina Emerges

Comet Catalina is ready for its close-up. The giant snowball from the outer Solar System, known formally as C/2013 US10 (Catalina), rounded the Sun last month and is now headed for its closest approach to Earth in January. With the glow of the Moon now also out of the way, morning observers in Earth's northern hemisphere are getting their best ever view of the new comet. And Comet Catalina is not disappointing. Although not as bright as early predictions, the comet is sporting both dust (lower left) and ion (upper right) tails, making it an impressive object for binoculars and long-exposure cameras. The featured image was taken last week from the Canary Islands, off the northwest coast of Africa. Sky enthusiasts around the world will surely be tracking the comet over the next few months to see how it evolves. via NASA http://ift.tt/1LYE6l1

A Force from Empty Space: The Casimir Effect

This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to energy fluctuations in the vacuum of empty space. The attraction is known as the Casimir Effect, named for its discoverer, who, 55 years ago, was trying to understand why fluids like mayonnaise move so slowly. Today, evidence indicates that most of the energy density in the universe is in an unknown form dubbed dark energy. The form and genesis of dark energy is almost completely unknown, but postulated as related to vacuum fluctuations similar to the Casimir Effect but generated somehow by space itself. This vast and mysterious dark energy appears to gravitationally repel all matter and hence will likely cause the universe to expand forever. Understanding vacuum energy is on the forefront of research not only to better understand our universe but also for stopping micro-mechanical machine parts from sticking together. via NASA http://ift.tt/1NbRbt8

Cygnus: Bubble and Crescent

These clouds of gas and dust drift through rich star fields along the plane of our Milky Way Galaxy toward the high flying constellation Cygnus. Caught within the telescopic field of view are the Soap Bubble (lower left) and the Crescent Nebula (upper right). Both were formed at a final phase in the life of a star. Also known as NGC 6888, the Crescent was shaped as its bright, central massive Wolf-Rayet star, WR 136, shed its outer envelope in a strong stellar wind. Burning through fuel at a prodigious rate, WR 136 is near the end of a short life that should finish in a spectacular supernova explosion. recently discovered Soap Bubble Nebula is likely a planetary nebula, the final shroud of a lower mass, long-lived, sun-like star destined to become a slowly cooling white dwarf. While both are some 5,000 light-years or so distant, the larger Crescent Nebula is around 25 light-years across. via NASA http://ift.tt/1NuTaMH

Enceladus: Ringside Water World

Saturn's icy moon Enceladus poses above the gas giant's icy rings in this Cassini spacecraft image. The dramatic scene was captured on July 29, while Cassini cruised just below the ring plane, its cameras looking back in a nearly sunward direction about 1 million kilometers from the moon's bright crescent. At 500 kilometers in diameter, Enceladus is a surprisingly active moon though, its remarkable south polar geysers are visible venting beyond a dark southern limb. In fact, data collected during Cassini's flybys and years of images have recently revealed the presence of a global ocean of liquid water beneath this moon's icy crust. Demonstrating the tantalizing liquid layer's global extent, the careful analysis indicates surface and core are not rigidly connected, with Enceladus rocking slightly back and forth in its orbit. via NASA http://ift.tt/1OIryTg

Nebulae in Aurigae

Rich in star clusters and nebulae, the ancient constellation of the Charioteer (Auriga) rides high in northern winter night skies. Composed from narrow and broadband filter data and spanning nearly 8 Full Moons (4 degrees) on the sky, this deep telescopic view shows off some of Auriga's celestial bounty. The field includes emission region IC 405 (top left) about 1,500 light-years distant. Also known as the Flaming Star Nebula, its red, convoluted clouds of glowing hydrogen gas are energized by hot O-type star AE Aurigae. IC 410 (top right) is significantly more distant, some 12,000 light-years away. The star forming region is famous for its embedded young star cluster, NGC 1893, and tadpole-shaped clouds of dust and gas. IC 417 and NGC 1931 at the lower right, the Spider and the Fly, are also young star clusters embedded in natal clouds that lie far beyond IC 405. Star cluster NGC 1907 is near the bottom edge of the frame, just right of center. The crowded field of view looks along the plane of our Milky Way galaxy, near the direction of the galactic anticenter. via NASA http://ift.tt/1OC4s0o