Astronomy Picture Of The Day - Page 11

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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 likely home to a central supermassive black hole.

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Clouds on a summer night frame this sea and skyscape, recorded earlier this month near Buenos Aires, Argentina. But planet Earth's clouds are not the only clouds on the scene. Starry clouds and nebulae along the southern hemisphere's summer Milky Way arc above the horizon, including the dark Coal Sack near the Southern Cross and the tantalizing pinkish glow of the Carina Nebula. Both the Large (top center) and Small Magellanic Clouds are also in view, small galaxies in their own right and satellites of the Milky Way up to 200,000 light-years distant. Alpha star of the Carina constellation and second brightest star in Earth's night, Canopus shines above about 300 light-years away. Still glinting in sunlight at an altitude of 400 kilometers, the orbiting International Space Station traces a long streak through the single, 5 minute, star-tracking exposure.

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On January 25 (UT) 2004, the Opportunity rover fell to Mars, making today the 9th anniversary of its landing. After more than 3,200 sols (Mars solar days) the golf cart-sized robot from Earth is still actively exploring the Red Planet, though its original mission plan was for three months. Having driven some 35 kilometers (22 miles) from its landing site, Opportunity's panoramic camera recorded the segments of this scene, in November and December of last year. The digitally stitched panorama spans more than 210 degrees across the Matijevic Hill area along the western rim of Endeavour Crater. Features dubbed Copper Cliff, a dark outcrop, appear at the left, and Whitewater Lake, a bright outcrop, at the far right. The image is presented here in a natural color approximation of what the scene would look like to human eyes.

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Moonlight illuminates a snowy scene in this night land and skyscape made on January 17 from Lower Miller Creek, Alaska, USA. Overexposed near the mountainous western horizon is the first quarter Moon itself, surrounded by an icy halo and flanked left and right by moondogs. Sometimes called mock moons, a more scientific name for the luminous apparitions is paraselenae (plural). Analogous to a sundog or parhelion, a paraselene is produced by moonlight refracted through thin, hexagonal, plate-shaped ice crystals in high cirrus clouds. As determined by the crystal geometry, paraselenae are seen at an angle of 22 degrees or more from the Moon. Compared to the bright lunar disk, paraselenae are faint and easier to spot when the Moon is low.

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Comet McNaught of 2007 has been, so far, the most photogenic comet of our time. After making quite a show in the northern hemisphere in early 2007 January, the comet moved south and developed a long and unusual dust tail that dazzled southern hemisphere observers. In this image, Comet McNaught was captured above Santiago, Chile. The bright comet dominates on the left while part of its magnificent tail spreads across the entire frame. From this vantage point in the Andes Mountains, one looks up toward Comet McNaught and a magnificent sky, across at a crescent moon, and down on clouds, atmospheric haze, and the city lights. The current year -- 2013 -- holds promise to be even better for comets than 2007. In early March, Comet PANSTARRS is on track to become visible to the unaided eye, while at the end of the year Comet ISON shows possibilities that include casting a tail that spreads across the sky, breaking up, and even becoming one of the brightest comets in recorded history.

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Clouds of glowing gas mingle with dust lanes in the Trifid Nebula, a star forming region toward the constellation of the Archer (Sagittarius). In the center, the three prominent dust lanes that give the Trifid its name all come together. Mountains of opaque dust appear on the right, while other dark filaments of dust are visible threaded throughout the nebula. A single massive star visible near the center causes much of the Trifid's glow. The Trifid, also known as M20, is only about 300,000 years old, making it among the youngest emission nebulae known. The nebula lies about 9,000 light years away and the part pictured here spans about 10 light years. The above image is a composite with luminance taken from an image by the 8.2-m ground-based Subaru Telescope, detail provided by the 2.4-m orbiting Hubble Space Telescope, color data provided by Martin Pugh and image assembly and processing provided by Robert Gendler.

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What would it be like to drive on the Moon? You don't have to guess -- humans have actually done it. Pictured above, Apollo 16 astronauts John Young and Charles Duke recorded video during one such drive in 1972, with a digital version now available on the web. No matter which direction it headed, the Lunar Rover traveled a path literally covered with rocks and craters. The first half of the above video shows the rover zipping about a moonscape near 10 kilometers per hour, while the second half shows a dash-cam like view. The Lunar Rover was deployed on the later Apollo missions as a way for astronauts to reach and explore terrain further from the Lunar Module basecamp than was possible by walking in cumbersome spacesuits. Possible future lunar missions that might deploy robotic rovers capable of beaming back similar videos include those by China, Russia, India, and Google X-Prize contestants.

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Have you ever watched the Moon rise? The slow rise of a nearly full moon over a clear horizon can be an impressive sight. One impressive moonrise was imaged two nights ago over Mount Victoria Lookout in Wellington, New Zealand. With detailed planning, an industrious astrophotographer placed a camera about two kilometers away and pointed it across the lookout to where the Moon would surely soon be making its nightly debut. The above single shot sequence is unedited and shown in real time -- it is not a time lapse. People on Mount Victoria Lookout can be seen in silhouette themselves admiring the dawn of Earth's largest satellite. Seeing a moonrise yourself is not difficult: it happens every day, although only half the time at night. Each day the Moon rises about fifty minutes later than the previous day, with a full moon always rising at sunset.

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The delightful Dark Doodad Nebula drifts through southern skies, a tantalizing target for binoculars in the constellation Musca, The Fly. The dusty cosmic cloud is seen against rich starfields just south of the prominent Coalsack Nebula and the Southern Cross. Stretching for about 3 degrees across this scene the Dark Doodad seems punctuated at its southern tip (lower left) by globular star cluster NGC 4372. Of course NGC 4372 roams the halo of our Milky Way Galaxy, a background object some 20,000 light-years away and only by chance along our line-of-sight to the Dark Doodad. The Dark Doodad's well defined silhouette belongs to the Musca molecular cloud, but its better known alliterative moniker was first coined by astro-imager and writer Dennis di Cicco in 1986 while observing comet Halley from the Australian outback. The Dark Doodad is around 700 light-years distant and over 30 light-years long.

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Beyond a fertile field of satellite communication antennas at Kennedy Space Center, an Atlas V rocket streaks into orbit in this long exposure photograph. In the thoughtfully composed image recorded on the evening of January 30, the antennas in the foreground bring to mind the rocket's payload, a Tracking and Data Relay Satellite (TDRS; sounds like TEE-dress). This TDRS-K is the first in a next-generation series adding to the constellation of NASA's communication satellites. Operating from geosynchronous orbit 22,300 miles (36,000 kilometers) above planet Earth, the network of TDRS satellites relays communications, data, and commands between spacecraft and ground stations. Formerly the TDRS network provided communications for space shuttle missions. In fact, many TDRS satellites were ferried as far as low Earth orbit on space shuttles. The TDRS network continues to support major spacecraft like the International Space Station, the Hubble Space Telescope, and the Fermi Gamma-ray Space Telescope.

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This infrared view from the Herschel Space Observatory explores the Andromeda Galaxy, the closest large spiral galaxy to our own Milky Way. Only 2.5 million light-years distant, the famous island universe is also known to astronomers as M31. Andromeda spans over 200,000 light-years making it more than twice the size of the Milky Way. Shown in false color, the image data reveal the cool dust lanes and clouds that still shine in the infrared but are otherwise dark and opaque at visual wavelengths. Red hues near the galaxy's outskirts represent the glow of dust heated by starlight to a few tens of degrees above absolute zero. Blue colors correspond to hotter dust warmed by stars in the more crowded central core. Also a tracer of molecular gas, the dust highlights Andromeda's prodigious reservoir of raw material for future star formation.

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This esthetic close-up of cosmic clouds and stellar winds features LL Orionis, interacting with the Orion Nebula flow. Adrift in Orion's stellar nursery and still in its formative years, variable star LL Orionis produces a wind more energetic than the wind from our own middle-aged Sun. As the fast stellar wind runs into slow moving gas a shock front is formed, analogous to the bow wave of a boat moving through water or a plane traveling at supersonic speed. The small, arcing, graceful structure just above and left of center is LL Ori's cosmic bow shock, measuring about half a light-year across. The slower gas is flowing away from the Orion Nebula's hot central star cluster, the Trapezium, located off the upper left corner of the picture. In three dimensions, LL Ori's wrap-around shock front is shaped like a bowl that appears brightest when viewed along the "bottom" edge. The beautiful picture is part of a large mosaic view of the complex stellar nursery in Orion, filled with a myriad of fluid shapes associated with star formation.

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Namibia has some of the darkest nights visible from any continent. It is therefore home to some of the more spectacular skyscapes, a few of which have been captured in the above time-lapse video. Visible at the movie start are unusual quiver trees perched before a deep starfield highlighted by the central band of our Milky Way Galaxy. This bright band of stars and gas appears to pivot around the celestial south pole as our Earth rotates. The remains of camel thorn trees are then seen against a sky that includes a fuzzy patch on the far right that is the Large Magellanic Cloud, a small satellite galaxy to the Milky Way. A bright sunlight-reflecting satellite passes quickly overhead. Quiver trees appear again, now showing their unusual trunks, while the Small Magellanic Cloud becomes clearly visible in the background. Artificial lights illuminate a mist that surround camel thorn trees in Deadvlei. In the final sequence, natural Namibian stone arches are captured against the advancing shadows of the setting moon. This video incorporates over 16,000 images shot over two years, and won top honors among the 2012 Travel Photographer of the Year awards.

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What if you saw your shadow on Mars and it wasn't human? Then you might be the robotic Curiosity rover currently exploring Mars. Curiosity landed in Gale Crater last August and has been busy looking for signs of ancient running water and clues that Mars could once have harbored life. Pictured above, Curiosity has taken a wide panorama that includes its own shadow in the direction opposite the Sun. The image was taken in November from a location dubbed Point Lake, although no water presently exists there. Curiosity has already discovered several indications of dried streambeds on Mars, and is scheduled to continue its exploration by climbing nearby Mt. Sharp over the next few years.

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The spiral arms of bright galaxy M106 sprawl through this remarkable multiframe portrait, composed of data from ground- and space-based telescopes. Also known as NGC 4258, M106 can be found toward the northern constellation Canes Venatici. The well-measured distance to M106 is 23.5 million light-years, making this cosmic scene about 80,000 light-years across. Typical in grand spiral galaxies, dark dust lanes, youthful blue star clusters, and pinkish star forming regions trace spiral arms that converge on the bright nucleus of older yellowish stars. But this detailed composite reveals hints of two anomalous arms that don't align with the more familiar tracers. Seen here in red hues, sweeping filaments of glowing hydrogen gas seem to rise from the central region of M106, evidence of energetic jets of material blasting into the galaxy's disk. The jets are likely powered by matter falling into a massive central black hole.

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