When did you first learn to identify this group of stars? Although they are familiar to many people around the world, different cultures have associated this asterism with different icons and folklore. Known in the USA as the Big Dipper, the stars are part of a constellation designated by the International Astronomical Union in 1922 as the Great Bear (Ursa Major). The recognized star names of these stars are (left to right) Alkaid, Mizar/Alcor, Alioth, Megrez, Phecda, Merak, and Dubhe. Of course, stars in any given constellation are unlikely to be physically related. But surprisingly, most of the Big Dipper stars do seem to be headed in the same direction as they plough through space, a property they share with other stars spread out over an even larger area across the sky. Their measured common motion suggests that they all belong to a loose, nearby star cluster, thought to be on average only about 75 light-years away and up to 30 light-years across. The cluster is more properly known as the Ursa Major Moving Group. The featured image captured the iconic stars recently above Pyramid Mountain in Alberta, Canada.
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Source: apod.nasa.gov
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Female Giant kingfisher (Megaceryle maxima) smashing a tilapia against a post to break its spine on Lake Naivasha, Kenya. To celebrate World Fisheries Day.

Our Sun

A broad hole in the corona was the Sun's dominant feature November 7-9, 2017, as shown in this image from NASA's Solar Dynamics Observatory. The hole is easily recognizable as the dark expanse across the top of the Sun and extending down in each side. Coronal holes are magnetically open areas on the Sun that allow high-speed solar wind to gush out into space. They always appear darker in extreme ultraviolet. This one was likely the source of bright aurora that shimmered for numerous observers, with some reaching down even to Nebraska.

Image Credit:NASA/GSFC/Solar Dynamics Observatory
Source: www.nasa.gov

Yes, but have you ever taken a selfie on Mars? The Curiosity rover on Mars has. This selfie was compiled from many smaller images -- which is why the mechanical arm holding the camera is not visible. (Although its shadow is!) Taken in mid-2015, the featured image shows not only the adventurous rover, but dark layered rocks, the light colored peak of Mount Sharp, and the rusting red sand that pervades Mars. If you look closely, you can even see that a small rock is stuck into one of Curiosity's aging wheels. Now nearing the end of 2017, Curiosity continues to explore the layers of sedimentary rocks it has discovered on Vera Rubin Ridge in order to better understand, generally, the ancient geologic history of Mars and, specifically, why these types of rocks exist there.

Now Available: The 2018 APOD Calendar

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A view from the observation deck at the top station of the Duquesne Incline in Pittsburgh, Pennsylvania, USA. The Duquesne Incline is one of two surviving inclines in Pittsburgh, the other being the Monongahela Incline.

Young stars themselves are clearing out their nursery in NGC 7822. Within the nebula, bright edges and complex dust sculptures dominate this detailed skyscape taken in infrared light by NASA's Wide Field Infrared Survey Explorer (WISE) satellite. NGC 7822 lies at the edge of a giant molecular cloud toward the northern constellation Cepheus, a glowing star forming region that lies about 3,000 light-years away. The atomic emission of light by the nebula's gas is powered by energetic radiation from the hot stars, whose powerful winds and light 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 cut off from their reservoir of star stuff. This field spans around 40 light-years at the estimated distance of NGC 7822.

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The Oceania-class cruise ship MS Marina docked in Sète, Hérault, France.

Friday, an old Moon smiled for early morning risers. Its waning sunlit crescent is captured in this atmospheric scene from clear skies near Bursa, Turkey, planet Earth. In the subtle twilight hues nearby celestial lights are Jupiter (top) and Venus shining close to the eastern horizon. But today, Saturday, the Moon will be new and early next week its waxing crescent will follow the setting Sun as it sinks in the west. Then, a young Moon's smile will join Saturn and Mercury in early evening skies.

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The Water Palace in Jaipur, India


This color-enhanced image of a massive, raging storm in Jupiter’s northern hemisphere was captured by NASA’s Juno spacecraft during its ninth close flyby of the gas giant planet.

The image was taken on Oct. 24, 2017 at 10:32 a.m. PDT (1:32 p.m. EDT). At the time the image was taken, the spacecraft was about 6,281 miles (10,108 kilometers) from the tops of the clouds of Jupiter at a latitude of 41.84 degrees. The spatial scale in this image is 4.2 miles/pixel (6.7 kilometers/pixel).

The storm is rotating counter-clockwise with a wide range of cloud altitudes. The darker clouds are expected to be deeper in the atmosphere than the brightest clouds. Within some of the bright “arms” of this storm, smaller clouds and banks of clouds can be seen, some of which are casting shadows to the right side of this picture (sunlight is coming from the left). The bright clouds and their shadows range from approximately 4 to 8 miles (7 to 12 kilometers) in both widths and lengths. These appear similar to the small clouds in other bright regions Juno has detected and are expected to be updrafts of ammonia ice crystals possibly mixed with water ice.

Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager.

JunoCam's raw images are available for the public to peruse and process into image products at:


More information about Juno is at:

https://www.nasa.gov/juno and http://missionjuno.swri.edu

Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/ Seán Doran

Image download options

Source: www.nasa.gov

The Tarantula Nebula is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud, about 180 thousand light-years away. The largest, most violent star forming region known in the whole Local Group of galaxies, the cosmic arachnid sprawls across this spectacular view composed with narrowband data centered on emission from ionized hydrogen and oxygen atoms. Within the Tarantula (NGC 2070), intense radiation, stellar winds and supernova shocks from the central young cluster of massive stars, cataloged as R136, energize the nebular glow and shape the spidery filaments. Around the Tarantula are other star forming regions with young star clusters, filaments, and blown-out bubble-shaped clouds. In fact, the frame includes the site of the closest supernova in modern times, SN 1987A, right of center. The rich field of view spans about 1 degree or 2 full moons, in the southern constellation Dorado. But were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky.

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The sky glows with soft pinkish colors of fading twilight in this serendipitous mountaintop vista. Taken in subfreezing temperatures, the thoughtfully composed photo shows snowy, rugged peaks seen from a mountain pass on November 14. Below lies the village of La Villa, Alta Badia in Italy's Dolomite Alps. Above the nestled village lights, the constellation Ursa Major hangs over the northern horizon. But most stunning is the intense fireball meteor. It was captured during the camera's exposure by chance as it flashed east to west across the northern horizon, under Ursa Major's familiar Big Dipper asterism. In fact, sightings of this major fireball meteor were widely reported in European skies, the most reported fireball event ever for planet Earth's American Meteor Society and the International Meteor Organization. The meteor's measured track over Germany is consistent with its origin near the active radiant of November's Taurid Meteor Shower. Taurid meteors are associated with dust from Encke's comet.

Watch: Leonid Meteor Shower

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Frontal view of the Central University Library of Bucharest and Carol I statue, Bucharest, Romania. The Central University Library was founded in 1895, 31 years after the foundation of the University of Bucharest, as the Carol I Library of the University Foundation. The building, designed by French architect Paul Gottereau, was completed in 1893 and opened on 14 March 1895. The volume collection has grown steadily from 3,400 volumes in 1899 to over 2 million in 1970.

Resupply ship approaches the Space Station

Orbital ATK's Cygnus resupply ship with its cymbal-ike UltraFlex solar arrays approaches the International Space Station's robotic arm Canadarm2 as both spacecraft fly into an orbital sunrise on Nov. 14, 2017.

The cargo craft carried almost 7,400 pounds of crew supplies, science experiments, spacewalk gear, station hardware and computer parts. New research will explore the effectiveness of antibiotics on astronauts and observe how plants absorb nutrients in microgravity. Other experiments will deploy CubeSats to explore laser communications and hybrid solar panels.

Image Credit: NASA

Source: www.nasa.gov
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The Kinkaku-ji, or temple of the Golden Pavillion, an UNESCO World Heritage Site, in Kyoto, Japan, as seen during Koyo, the autumnal season of colorful leaves.

Visualization of aerosols in atmosphere

How can you see the atmosphere? The answer is blowing in the wind. Tiny particles, known as aerosols, are carried by winds around the globe. This visualization uses data from NASA satellites combined with our knowledge of physics and meteorology to track three aerosols: dust, smoke, and sea salt.

Sea salt, shown here in blue, is picked up by winds passing over the ocean. As tropical storms and hurricanes form, the salt particles are concentrated into the spiraling shape we all recognize. With their movements, we can follow the formation of Hurricane Irma and see the dust from the Sahara, shown in tan, get washed out of the storm center by the rain. Advances in computing speed allow scientists to include more details of these physical processes in their simulations of how the aerosols interact with the storm systems. The increased resolution of the computer simulation is apparent in fine details like the hurricane bands spiraling counter-clockwise. Computer simulations let us see how different processes fit together and evolve as a system.

By using mathematical models to represent nature we can separate the system into component parts and better understand the underlying physics of each. Today's research improves next year's weather forecasting ability. Hurricane Ophelia was very unusual. It headed northeast, pulling in Saharan dust and smoke from wildfires in Portugal, carrying both to Ireland and the UK. This aerosol interaction was very different from other storms of the season. As computing speed continues to increase, scientists will be able to bring more scientific details into the simulations, giving us a deeper understanding of our home planet.

Watch the video: https://www.youtube.com/watch?v=h1eRp0EGOmE

Image Credit: NASA's Goddard Space Flight Center

Source: www.nasa.gov

Found among the rich starfields of the Milky Way, star cluster NGC 7789 lies about 8,000 light-years away toward the constellation Cassiopeia. A late 18th century deep sky discovery of astronomer Caroline Lucretia Herschel, the cluster is also known as Caroline's Rose. Its flowery visual appearance in small telescopes is created by the cluster's nestled complex of stars and voids. Now estimated to be 1.6 billion years young, the galactic or open cluster of stars also shows its age. All the stars in the cluster were likely born at the same time, but the brighter and more massive ones have more rapidly exhausted the hydrogen fuel in their cores. These have evolved from main sequence stars like the Sun into the many red giant stars shown with a yellowish cast in this lovely color composite. Using measured color and brightness, astronomers can model the mass and hence the age of the cluster stars just starting to "turn off" the main sequence and become red giants. Over 50 light-years across, Caroline's Rose spans about half a degree (the angular size of the Moon) near the center of the wide-field telescopic image.

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Agriocnemis pieris, White Dartlet, belongs to Agriocnemis genus of small damselflies (commonly known as Wisps or Dartlets) in Coenagrionidae's subfamily Agriocnemidinae.

Mariner 9 views of shield volcano on Mars

On November 14, 1971, Mariner 9, the first spacecraft to orbit the Red Planet took this and other images of a Martian shield volcano, approximately 25 miles across at the crater. The images were photographed consecutively with the craft's wide-angle and telephoto lenses. The summit crater and grooves down the flank probably were produced by subsidence flowing subsurface movement of magma. Mariner 9 was also the first spacecraft to orbit another planet and was designed to continue the atmospheric studies begun by Mariners 6 and 7, and mapped more than 70% of the Martian surface.

Image Credit: NASA

Source: www.nasa.gov

The well-known Pleiades star cluster is slowly destroying part of a passing cloud of gas and dust. The Pleiades is the brightest open cluster of stars on Earth's sky and can be seen from almost any northerly location with the unaided eye. The passing young dust cloud is thought to be part of Gould's Belt, an unusual ring of young star formation surrounding the Sun in the local Milky Way Galaxy. Over the past 100,000 years, part of Gould's Belt is by chance moving right through the older Pleiades and is causing a strong reaction between stars and dust. Pressure from the stars' light significantly repels the dust in the surrounding blue reflection nebula, with smaller dust particles being repelled more strongly. A short-term result is that parts of the dust cloud have become filamentary and stratified. The featured deep image also captured Comet C/2015 ER61 (PanSTARRS) on the lower left.

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Porsche 911 Carrera RSR, built in 1974, at the Oldtimer Grand Prix of the AvD 2011 at the Nürburgring, Germany, just before the Mercedes-Arena.