NASA Astronomy Picture of the Day 2016-11

Arp 299: Black Holes in Colliding Galaxies

Is only one black hole spewing high energy radiation -- or two? To help find out, astronomers trained NASA's Earth-orbiting NuSTAR and Chandra telescopes on Arp 299, the enigmatic colliding galaxies expelling the radiation. The two galaxies of Arp 299 have been locked in a gravitational combat for millions of years, while their central black holes will soon do battle themselves. Featured, the high-resolution visible-light image was taken by Hubble, while the superposed diffuse glow of X-ray light was imaged by NuSTAR and shown in false-color red, green, and blue. NuSTAR observations show that only one of the central black holes is seen fighting its way through a region of gas and dust -- and so absorbing matter and emitting X-rays. The energetic radiation, coming only from the galaxy center on the right, is surely created nearby -- but outside -- the central black hole's event horizon. In a billion years or so, only one composite galaxy will remain, and only one central supermassive black hole. Soon thereafter, though, another galaxy may enter the fray. Transparent Science: Browse 1,350+ codes in the Astrophysics Source Code Library

M27: The Dumbbell Nebula

The first hint of what will become of our Sun 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, shown above 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.

NGC 253: Dusty Island Universe

Shiny NGC 253 is one of the brightest spiral galaxies visible, and also one of the dustiest. Some call it the Silver Dollar Galaxy for its appearance in small telescopes, or just the Sculptor Galaxy for its location within the boundaries of the southern constellation Sculptor. First swept up in 1783 by mathematician and astronomer Caroline Herschel, the dusty island universe lies a mere 10 million light-years away. About 70 thousand light-years across, NGC 253 is the largest member of the Sculptor Group of Galaxies, the nearest to our own Local Group of Galaxies. In addition to its spiral dust lanes, tendrils of dust seem to be rising from a galactic disk laced with young star clusters and star forming regions in this sharp color image. The high dust content accompanies frantic star formation, earning NGC 253 the designation of a starburst galaxy. NGC 253 is also known to be a strong source of high-energy x-rays and gamma rays, likely due to massive black holes near the galaxy's center.

Portrait of NGC 281

Look through the cosmic cloud cataloged as NGC 281 and you might miss the stars of open cluster IC 1590. Still, formed within the nebula that cluster's young, massive stars ultimately power the pervasive nebular glow. The eye-catching shapes looming in this portrait of NGC 281 are sculpted columns and dense dust globules seen in silhouette, eroded by intense, energetic winds and radiation from the hot cluster stars. If they survive long enough, the dusty structures could also be sites of future star formation. Playfully called the Pacman Nebula because of its overall shape, NGC 281 is about 10,000 light-years away in the constellation Cassiopeia. This sharp composite image was made through narrow-band filters, combining emission from the nebula's hydrogen, sulfur, and oxygen atoms in green, red, and blue hues. It spans over 80 light-years at the estimated distance of NGC 281.

ISS Fisheye Fly-Through

Shot in Ultra HD, this stunning video can take you on a tour of the International Space Station. A fisheye lens with sharp focus and extreme depth of field provides an immersive visual experience of life in the orbital outpost. In the 18 minute fly-through, your point of view will float serenely while you watch our fair planet go by 400 kilometers below the seven-windowed Cupola, and explore the interior of the station's habitable nodes and modules from an astronaut's perspective. The modular International Space Station is Earth's largest artificial satellite, about the size of a football field in overall length and width. Its total pressurized volume is approximately equal to that of a Boeing 747 aircraft.

Starburst Cluster in NGC 3603

A mere 20,000 light-years from the Sun lies NGC 3603, a resident of the nearby Carina spiral arm of our Milky Way Galaxy. NGC 3603 is well known to astronomers as one of the Milky Way's largest star-forming regions. The central open star cluster contains thousands of stars more massive than our Sun, stars that likely formed only one or two million years ago in a single burst of star formation. In fact, nearby NGC 3603 is thought to contain a convenient example of the massive star clusters that populate much more distant starburst galaxies. Surrounding the cluster are natal clouds of glowing interstellar gas and obscuring dust, sculpted by energetic stellar radiation and winds. Recorded by the Hubble Space Telescope, the image spans about 17 light-years. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter

Inverted City Beneath Clouds

How could that city be upside-down? The city, Chicago, was actually perfectly right-side up. The long shadows it projected onto nearby Lake Michigan near sunset, however, when seen in reflection, made the buildings appear inverted. This fascinating, puzzling, yet beautiful image was captured by a photographer in 2014 on an airplane on approach to Chicago's O'Hare International Airport. The Sun can be seen both above and below the cloud deck, with the latter reflected in the calm lake. As a bonus, if you look really closely -- and this is quite a challenge -- you can find another airplane in the image, likely also on approach to the same airport.

The Cosmic Web of the Tarantula Nebula

It is the largest and most complex star forming region in the entire galactic neighborhood. Located in the Large Magellanic Cloud, a small satellite galaxy orbiting our Milky Way galaxy, the region's spidery appearance is responsible for its popular name, the Tarantula nebula. This tarantula, however, is about 1,000 light-years across. Were it placed at the distance of Milky Way's Orion Nebula, only 1,500 light-years distant and the nearest stellar nursery to Earth, it would appear to cover about 30 degrees (60 full moons) on the sky. Intriguing details of the nebula are visible in the featured image shown in colors emitted predominantly by hydrogen and oxygen. The spindly arms of the Tarantula nebula surround NGC 2070, a star cluster that contains some of the brightest, most massive stars known, visible in blue in the image center. Since massive stars live fast and die young, it is not so surprising that the cosmic Tarantula also lies near the site of the closest recent supernova.

M63: The Sunflower Galaxy from Hubble

One of the bright spiral galaxies visible in the north sky is M63, the Sunflower Galaxy. M63, also catalogued as NGC 5055, can be found with a small telescope toward the constellation of Hunting Dogs (Canes Venatici). The featured picture from the Hubble Space Telescope exhibits the center of M63, complete with long winding spiral arms glowing blue from a few bright young stars, emission nebulae glowing red from hot ionized hydrogen gas, and dark dust in numerous filaments. M63 interacts gravitationally with M51 (the Whirlpool Galaxy) and several smaller galaxies. Light takes about 35 million years to reach us from M63, and about 60,000 years to cross the spiral galaxy. Stars in the outer regions of the Sunflower Galaxy rotate about the center at a speed so high that, given the matter seen and assuming normal gravity, they should fly off into space. The fact that the stars remain indicates the presence of sort of invisible, gravitationally-binding, dark matter. Free Download: APOD 2017 Calendar: NASA Images

Great Rift Near the Center of the Milky Way

Over 100 telescopic image panels in this stunning vertical mosaic span about 50 degrees across the night sky. They follow part of the Great Rift, the dark river of dust and molecular gas that stretches along the plane of our Milky Way Galaxy. Start at top center and you can follow the galactic equator down through brighter stars in constellations Aquila, Serpens Cauda, and Scutum. At the bottom is Sagittarius near the center of the Milky Way. Along the way you'll encounter many obscuring dark nebulae hundreds of light-years distant flanked by bands of Milky Way starlight, and the telltale reddish glow of starforming regions. Notable Messier objects include The Eagle (M16) and Omega (M17) nebulae, the Sagittarius Star Cloud (M24), the beautiful Trifid (M20) and the deep Lagoon (M8).

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 stand out 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 emission line and color combination has become well-known as the Hubble palette. The atomic emission is powered by energetic radiation from the central hot stars. Their powerful winds and radiation sculpt and erode the denser pillar shapes and clear out a characteristic cavity light-years across the center of the natal cloud. 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 of view spans over 40 light-years at the estimated distance of NGC 7822.

NGC 891 vs Abell 347

Galaxies abound in this well-chosen field of view that spans about 1 degree on the sky toward the northern constellation Andromeda. At top right is large spiral galaxy NGC 891, 100 thousand light-years across and seen almost exactly edge-on. About 30 million light-years distant, NGC 891 looks a lot like our own Milky Way with a flattened, thin, galactic disk. Its disk and central bulge are cut along the middle by dark, obscuring dust clouds. Scattered toward the lower left, and beyond a foreground of Milky Way stars, are members of galaxy cluster Abell 347. Nearly 240 million light-years away, Abell 347 shows off its own large galaxies in the sharp telescopic image. They are similar to NGC 891 in physical size but located almost 8 times farther away, so Abell 347 galaxies have roughly one eighth the apparent size of NGC 891. Watch: Closest Full Moon since 1948

Super Moon vs. Micro Moon

What is so super about tomorrow's supermoon? Tomorrow, a full moon will occur that appears slightly larger and brighter than usual. The reason is that the Moon's fully illuminated phase occurs within a short time from perigee - when the Moon is its closest to the Earth in its elliptical orbit. Although the precise conditions that define a supermoon vary, tomorrow's supermoon will undoubtedly qualify because it will be the closest, largest, and brightest full moon in over 65 years. One reason supermoons are popular is because they are so easy to see -- just go outside at sunset and watch an impressive full moon rise! Since perigee actually occurs tomorrow morning, tonight's full moon, visible starting at sunset, should also be impressive. Pictured here, a supermoon from 2012 is compared to a micromoon -- when a full Moon occurs near the furthest part of the Moon's orbit -- so that it appears smaller and dimmer than usual. Given many definitions, at least one supermoon occurs each year, with another one coming next month (moon-th). However, a full moon will not come this close to Earth again until 2034.

Supermoon and Space Station

What are those specks in front of the Moon? They are silhouettes of the International Space Station (ISS). Using careful planning and split-second timing, a meticulous lunar photographer captured ten images of the ISS passing in front of last month's full moon. But this wasn't just any full moon -- this was the first of the three consecutive 2016 supermoons. A supermoon is a full moon that appears a few percent larger and brighter than most other full moons. The featured image sequence was captured near Dallas, Texas. Occurring today is the second supermoon of this series, a full moon that is the biggest and brightest not only of the year, but of any year since 1948. To see today's super-supermoon yourself, just go outside at night and look up. The third supermoon of this year's series will occur in mid-December. APOD Gallery: Best of Supermoon 2016

Cold Weather Delayed over North America

Why is it so warm in northern North America? Usually during this time of year -- mid-November -- temperatures average as much as 30 degrees colder. Europe is not seeing a similar warming. One factor appears to be an unusually large and stable high pressure region that has formed over Canada, keeping normally colder arctic air away. Although the fundamental cause of any weather pattern is typically complex, speculation holds that this persistent Canadian anticyclonic region is related to warmer than average sea surface temperatures in the mid-Pacific -- an El Niño -- operating last winter. North Americans should enjoy it while it lasts, though. In the next week or two, cooler-than-average temperatures now being recorded in the mid-Pacific -- a La Niña -- might well begin to affect North American wind and temperature patterns. APOD Galleries: Best of Supermoon 2016 (I), Best of Supermoon 2016 (II)

The Heart and Soul Nebulas

Is the heart and soul of our Galaxy located in Cassiopeia? Possibly not, but that is where two bright emission nebulas nicknamed Heart and Soul can be found. The Heart Nebula, officially dubbed IC 1805 and visible in the featured image on the right, has a shape reminiscent of a classical heart symbol. Both nebulas shine brightly in the red light of energized hydrogen. Several young open clusters of stars populate the image and are visible here in blue, including the nebula centers. Light takes about 6,000 years to reach us from these nebulas, which together span roughly 300 light years. Studies of stars and clusters like those found in the Heart and Soul Nebulas have focused on how massive stars form and how they affect their environment. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter

Soyuz vs Supermoon

Faster than a speeding bullet, more powerful than a locomotive, and able to leap tall buildings in a single bound, this Soyuz rocket stands on the launch pad at Baikonur Cosmodrome in Kazakhstan on November 14. Beyond it rises a supermoon, but fame for exceptional feats of speed, strength, and agility is not the reason November's Full Moon was given this popular name. Instead, whenever a Full Moon shines near perigee, the closest point in its elliptical orbit around Earth, it appears larger and brighter than other more distant Full Moons, and so a supermoon is born. In fact, November's supermoon was the second of three consecutive supermoons in 2016. It was also the closest and most superest Full Moon since 1948. Meanwhile, the mild mannered Soyuz rocket is scheduled to launch its Expedition 50/51 crew to the International Space Station today, November 17.

Philadelphia Perigee Full Moon

A supermoon sets over the metropolis of Philadelphia in this twilight snapshot captured on November 14 at 6:21am Eastern Standard Time. Within hours of the Moon's exact full phase, that time does correspond to a lunar perigee or the closest point in the Moon's elliptical orbit around our fair planet. Slightly bigger and brighter at perigee, this Full Moon is still flattened and distorted in appearance by refraction in atmospheric layers along the sight-line near the horizon. Also like more ordinary Full Moons, it shines with the warm color of sunlight. Joined by buildings along the Philadelphia skyline, the perigee full moonlight is reflected in the waters of the mighty Cooper River.

IC 5070: A Dusty Pelican in the Swan

The recognizable profile of the Pelican Nebula soars nearly 2,000 light-years away in the high flying constellation Cygnus, the Swan. Also known as IC 5070, this interstellar cloud of gas and dust is appropriately found just off the "east coast" of the North America Nebula (NGC 7000), another surprisingly familiar looking emission nebula in Cygnus. Both Pelican and North America nebulae are part of the same large and complex star forming region, almost as nearby as the better-known Orion Nebula. From our vantage point, dark dust clouds (upper left) help define the Pelican's eye and long bill, while a bright front of ionized gas suggests the curved shape of the head and neck. This striking synthesized color view utilizes narrowband image data recording the emission of hydrogen and oxygen atoms in the cosmic cloud. The scene spans some 30 light-years at the estimated distance of the Pelican Nebula.

NGC 4414: A Flocculent Spiral Galaxy

How much mass do flocculent spirals hide? The featured true color image of flocculent spiral galaxy NGC 4414 was taken with the Hubble Space Telescope to help answer this question. The featured image was augmented with data from the Sloan Digital Sky Survey (SDSS). Flocculent spirals -- galaxies without well-defined spiral arms -- are a quite common form of galaxy, and NGC 4414 is one of the closest. Stars and gas near the visible edge of spiral galaxies orbit the center so fast that the gravity from a large amount of unseen dark matter must be present to hold them together. Understanding the matter and dark matter distribution of NGC 4414 helps humanity calibrate the rest of the galaxy and, by deduction, flocculent spirals in general. Further, calibrating the distance to NGC 4414 helps humanity calibrate the cosmological distance scale of the entire visible universe. Free Download: APOD 2017 Calendar: NASA Images

Nova over Thailand

A nova in Sagittarius is bright enough to see with binoculars. Discovered last month by the All-Sky Automated Survey for Supernovae (ASAS-SN), the stellar explosion even approached the limit of naked-eye visibility last week. A classical nova results from a thermonuclear explosion on the surface of a white dwarf star -- a dense star having the size of our Earth but the mass of our Sun. In the featured image, the nova was captured last week above ancient Wat Mahathat in Sukhothai, Thailand. To see Nova Sagittarius 2016 yourself, just go out just after sunset and locate near the western horizon the constellation of the Archer (Sagittarius), popularly identified with an iconic teapot. Also visible near the nova is the very bright planet Venus. Don’t delay, though, because not only is the nova fading, but that part of the sky is setting continually closer to sunset.

Pluto's Sputnik Planum

Is there an ocean below Sputnik Planum on Pluto? The unusually smooth 1000-km wide golden expanse, visible in the featured image from New Horizons, appears segmented into convection cells. But how was this region created? One hypothesis now holds the answer to be a great impact that stirred up an underground ocean of salt water roughly 100-kilometers thick. The featured image of Sputnik Planum, part of the larger heart-shaped Tombaugh Regio, was taken last July and shows true details in exaggerated colors. Although the robotic New Horizons spacecraft is off on a new adventure, continued computer-modeling of this surprising surface feature on Pluto is likely to lead to more refined speculations about what lies beneath.

NGC 7635: Bubble in a Cosmic Sea

Do you see the bubble in the center? Seemingly adrift in a cosmic sea of stars and glowing gas, the delicate, floating apparition in this widefield view is cataloged as NGC 7635 - The Bubble Nebula. A mere 10 light-years wide, the tiny Bubble Nebula and the larger complex of interstellar gas and dust clouds are found about 11,000 light-years distant, straddling the boundary between the parental constellations Cepheus and Cassiopeia. Also included in the breathtaking vista is open star cluster M52 (upper left), some 5,000 light-years away. The featured image spans about two degrees on the sky corresponding to a width of about 375 light-years at the estimated distance of the Bubble Nebula. Follow APOD on: Facebook, Google Plus, Instagram, or Twitter

Ring Scan

Scroll right and you can cruise along the icy rings of Saturn. This high resolution scan is a mosaic of images presented in natural color. The images were recorded in May 2007 over about 2.5 hours as the Cassini spacecraft passed above the unlit side of the rings. To help track your progress, major rings and gaps are labeled along with the distance from the center of the gas giant in kilometers. The alphabetical designation of Saturn's rings is historically based on their order of discovery; rings A and B are the bright rings separated by the Cassini division. In order of increasing distance from Saturn, the seven main rings run D,C,B,A,F,G,E. (Faint, outer rings G and E are not imaged here.) Four days from now, on November 29, Cassini will make a close flyby of Saturn's moon Titan and use the large moon's gravity to nudge the spacecraft into a series of 20 daring, elliptical, ring-grazing orbits. Diving through the ring plane just 11,000 kilometers outside the F ring (far right) Cassini's first ring-graze will be on December 4.

Apollo 17 VIP Site Anaglyph

Get out your red/blue glasses and check out this stereo scene from Taurus-Littrow valley on the Moon! The color anaglyph features a detailed 3D view of Apollo 17's Lunar Rover in the foreground -- behind it lies the Lunar Module and distant lunar hills. Because the world was going to be able to watch the Lunar Module's ascent stage liftoff via the rover's TV camera, this parking place was also known as the VIP Site. In December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon, while colleague Ronald Evans orbited overhead. The crew returned with 110 kilograms of rock and soil samples, more than from any of the other lunar landing sites. Cernan and Schmitt are still the last to walk (or drive) on the Moon.

East to West, Light and Shadow

On this November morning an old crescent Moon and morning star rise just before the Sun in a wide panoramic skyscape from Kenya's Amboseli National Park. Still below the limbs of an acacia tree and the eastern horizon, the Sun's position is easy to find though. It's marked at the left by the subtle convergence of light and shadow in the dawn sky. Known as crepuscular rays, the warm-colored rays of sunlight are outlined by shadows cast by unseen clouds near the horizon. Arcing above the profile of Mount Kilimanjaro, toward the right the rays of light and shadow converge at the western horizon. There known as anti-crepuscular rays, they indicate the point opposite the rising sun. The cloud shadows are very nearly parallel, but converge toward the distant horizons because of perspective.

Verona Rupes: Tallest Known Cliff in the Solar System

Could you survive a jump off the tallest cliff in the Solar System? Quite possibly. Verona Rupes on Uranus' moon Miranda is estimated to be 20 kilometers deep -- ten times the depth of the Earth's Grand Canyon. Given Miranda's low gravity, it would take about 12 minutes for a thrill-seeking adventurer to fall from the top, reaching the bottom at the speed of a racecar -- about 200 kilometers per hour. Even so, the fall might be survivable given proper airbag protection. The featured image of Verona Rupes was captured by the passing Voyager 2 robotic spacecraft in 1986. How the giant cliff was created remains unknown, but is possibly related to a large impact or tectonic surface motion.

Arp 240: A Bridge between Spiral Galaxies from Hubble

Why is there a bridge between these two spiral galaxies? Made of gas and stars, the bridge provides strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity. Known together as Arp 240 but individually as NGC 5257 and NGC 5258, computer modelling and the ages of star clusters indicate that the two galaxies completed a first passage near each other only about 250 million years ago. Gravitational tides not only pulled away matter, they compress gas and so caused star formation in both galaxies and the unusual bridge. Galactic mergers are thought to be common, with Arp 240 representing a snapshot of a brief stage in this inevitable process. The Arp 240 pair are about 300 million light-years distant and can be seen with a small telescope toward the constellation of Virgo. Repeated close passages should ultimately result in a merger and with the emergence of a single combined galaxy. Free Download: APOD 2017 Calendar: NASA Images

W5: The Soul of Star Formation

Where do stars form? Many times, stars form in energetic regions where gas and dark dust are pushed around in chaotic mayhem. Pictured, bright massive stars near the center of W5, the Soul Nebula, are exploding and emitting ionizing light and energetic winds. The outward-moving light and gas push away and evaporate much surrounding gas and dust, but leave pillars of gas behind dense protective knots. Inside these knots, though, stars also form. The featured image highlights the inner sanctum of W5, an arena spanning about 1,000 light years that is rich in star forming pillars. The Soul Nebula, also cataloged as IC 1848, lies about 6,500 light years away toward the constellation of the Queen of Aethopia (Cassiopeia). Likely, in few hundred million years, only a cluster of the resulting stars will remain. Then, these stars will drift apart.

Milky Way over Shipwreck

What happened to this ship? It was carried aground by a giant storm that struck the coast of Argentina in 2002. The pictured abandoned boat, dubbed Naufragio del Chubasco, wrecked near the nearly abandoned town of Cabo Raso (population: 1). The rusting ship provides a picturesque but perhaps creepy foreground for the beautiful sky above. This sky is crowned by the grand arch of our Milky Way and features galaxies including the Large and Small Magellanic Clouds, stars including Canopus and Altair, planets including Mars and Neptune, and nebulas including the Lagoon, Carina, and the Coal Sack. The mosaic was composed from over 80 images taken in early September. A 360-degree interactive panoramic version of this image is also available. The adventurous astrophotographer reports that the creepiest part of taking this picture was not the abandoned ship, but the unusual prevalence of black and hairy caterpillars.

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