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Astronomy Picture of the Day (General/Chat)

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  • Astronomy Picture of the Day -- Cat's Eye Wide and Deep

    05/28/2016 4:18:20 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | Saturday, May 28, 2016 | (see photo credit)
    Explanation: The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its more familiar outlines are seen in the brighter central region of the nebula in this impressive wide-angle view. But the composite image combines many short and long exposures to also reveal an extremely faint outer halo. At an estimated distance of 3,000 light-years, the faint outer halo is over 5 light-years across. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. More recently, some planetary nebulae are found to have halos like this...
  • Astronomy Picture of the Day -- The Great Carina Nebula

    05/28/2016 4:14:03 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | Friday, May 27, 2016 | (see photo credit)
    Explanation: A jewel of the southern sky, the Great Carina Nebula, also known as NGC 3372, spans over 300 light-years, one of our galaxy's largest star forming regions. Like the smaller, more northerly Great Orion Nebula, the Carina Nebula is easily visible to the unaided eye, though at a distance of 7,500 light-years it is some 5 times farther away. This gorgeous telescopic close-up reveals remarkable details of the region's central glowing filaments of interstellar gas and obscuring cosmic dust clouds. The field of view is over 50 light-years across. The Carina Nebula is home to young, extremely massive stars,...
  • Astronomy Picture of the Day -- IC 5067 in the Pelican Nebula

    05/26/2016 5:23:38 AM PDT · by SunkenCiv · 17 replies
    NASA ^ | Thursday, May 26, 2016 | (see photo credit)
    Explanation: The prominent ridge of emission featured in this sharp, colorful skyscape is cataloged as IC 5067. Part of a larger emission nebula with a distinctive shape, popularly called The Pelican Nebula, the ridge spans about 10 light-years following the curve of the cosmic pelican's head and neck. This false-color view also translates the pervasive glow of narrow emission lines from atoms in the nebula to a color palette made popular in Hubble Space Telescope images of star forming regions. Fantastic, dark shapes inhabiting the 1/2 degree wide field are clouds of cool gas and dust sculpted by the winds...
  • Astronomy Picture of the Day -- NGC 5078 and Friends

    05/25/2016 3:16:55 PM PDT · by SunkenCiv · 1 replies
    NASA ^ | Wednesday, May 25, 2016 | (see photo credit)
    Explanation: This sharp telescopic field of view holds two bright galaxies. Barred spiral NGC 5101 (top right) and nearly edge-on system NGC 5078 are separated on the sky by about 0.5 degrees or about the apparent width of a full moon. Found within the boundaries of the serpentine constellation Hydra, both are estimated to be around 90 million light-years away and similar in size to our own large Milky Way galaxy. In fact, if they both lie at the same distance their projected separation would be only 800,000 light-years or so. That's easily less than half the distance between the...
  • Astronomy Picture of the Day -- Milky Way Over the Spanish Peaks

    05/24/2016 4:28:10 AM PDT · by SunkenCiv · 14 replies
    NASA ^ | Tuesday, May 24, 2016 | (see photo credit)
    Explanation: That's not lightning, and it did not strike between those mountains. The diagonal band is actually the central band of our Milky Way Galaxy, while the twin peaks are actually called the Spanish Peaks -- but located in Colorado, USA. Although each Spanish peak is composed of a slightly different type of rock, both are approximately 25 million years old. This serene yet spirited image composite was meticulously created by merging a series of images all taken from the same location on one night and early last month. In the first series of exposures, the background sky was built...
  • Astronomy Picture of the Day -- Inside a Daya Bay Antineutrino Detector

    05/22/2016 9:30:47 PM PDT · by SunkenCiv · 7 replies
    NASA ^ | Monday, May 23, 2016 | (see photo credit)
    Explanation: Why is there more matter than antimatter in the Universe? To better understand this facet of basic physics, energy departments in China and the USA led in the creation of the Daya Bay Reactor Neutrino Experiment. Located under thick rock about 50 kilometers northeast of Hong Kong, China, eight Daya Bay detectors monitor antineutrinos emitted by six nearby nuclear reactors. Featured here, a camera looks along one of the Daya Bay detectors, imaging photon sensors that pick up faint light emitted by antineutrinos interacting with fluids in the detector. Early results indicate an unexpectedly high rate of one type...
  • Astronomy Picture of the Day -- LL Orionis: When Cosmic Winds Collide

    05/22/2016 5:31:41 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | Sunday, May 22, 2016 | (see photo credit)
    Explanation: What created this great arc in space? This arcing, graceful structure is actually a bow shock about half a light-year across, created as the wind from young star LL Orionis collides 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 slower...
  • Astronomy Picture of the Day -- Milky Way and Planets Near Opposition

    05/21/2016 12:47:18 PM PDT · by SunkenCiv · 6 replies
    NASA ^ | Saturday, May 21, 2016 | (see photo credit)
    Explanation: In this early May night skyscape, a mountain road near Bursa, Turkey seems to lead toward bright planets Mars and Saturn and the center of our Milky Way Galaxy, a direction nearly opposite the Sun in planet Earth's sky. The brightest celestial beacon on the scene, Mars, reaches its opposition tonight and Saturn in early June. Both will remain nearly opposite the Sun, up all night and close to Earth for the coming weeks, so the time is right for good telescopic viewing. Mars and Saturn form the tight celestial triangle with red giant star Antares just right of...
  • Astronomy Picture of the Day -- 3D Mercury Transit

    05/20/2016 10:54:00 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | Friday, May 20, 2016 | (see photo credit)
    Explanation: On May 9, innermost planet Mercury crossed IN FRONT of the Sun. Though pictures project the event in only two dimensions, a remarkable three dimensional perspective on the transit is possible by free viewing this stereo pair. The images were made 23 minutes apart and rotated so that Mercury's position shifts horizontally between the two. As a result, Mercury's orbital motion produced an exaggerated parallax simulating binocular vision. Between the two exposures, the appropriately named planet's speedy 47.4 kilometer per second orbital velocity actually carried it over 65,000 kilometers. Taken first, the left image is intended for the right...
  • Astronomy Picture of the Day -- The Surface of Europa

    05/19/2016 10:17:59 AM PDT · by SunkenCiv · 11 replies
    NASA ^ | Thursday, May 19, 2016 | (see photo credit)
    Explanation: An enhanced-color view, this image covers a 350 by 750 kilometer swath across the surface of Jupiter's tantalizing moon Europa. The close-up combines high-resolution image data with lower resolution color data from observations made in 1998 by the Galileo spacecraft. Smooth ice plains, long fractures, and jumbled blocks of chaos terrain are thought to hide a deep ocean of salty liquid water beneath. Though the ice-covered alien ocean world is outside the Solar System's habitable zone, new studies show the potential chemistry driving its oxygen and hydrogen production, a key indicator of the energy available for life, could produce...
  • Astronomy Picture of the Day -- Halo from Atacama

    05/18/2016 10:27:18 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | Wednesday, May 18, 2016 | (see photo credit)
    Explanation: Influenced by the strong Pacific El Nino, cloudy skies have more often come to Chile's high Atacama Desert this season, despite its reputation as an astronomer's paradise. Located in one of the driest, darkest places on planet Earth, domes of the region's twin 6.5 meter Magellan telescopes of Carnegie Las Campanas Observatory were closed on May 13. Still, a first quarter Moon and bright stars shine through in this panoramic night skyscape, the lunar disk surrounded by a beautiful, bright halo. The angular radius of the halo is 22 degrees. Not determined by the brightness or phase of the...
  • Astronomy Picture of the Day -- The Orion Nebula in Visible and Infrared

    05/17/2016 2:52:36 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | Tuesday, May 17, 2016 | (see photo credit)
    Explanation: The Great Nebula in Orion is a colorful place. Visible to the unaided eye, it appears as a small fuzzy patch in the constellation of Orion. Long exposure, multi-wavelength images like this, however, show the Orion Nebula to be a busy neighborhood of young stars, hot gas, and dark dust. This digital composite features not only three colors of visible light but four colors of infrared light taken by NASA's orbiting Spitzer Space Telescope as well. The power behind much of the Orion Nebula (M42) is the Trapezium - four of the brightest stars in the nebula. Many of...
  • Astronomy Picture of the Day -- Clouds of the Carina Nebula

    05/16/2016 6:15:36 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | Monday, May 16, 2016 | (see photo credit)
    Explanation: What forms lurk in the mists of the Carina Nebula? The dark ominous figures are actually molecular clouds, knots of molecular gas and dust so thick they have become opaque. In comparison, however, these clouds are typically much less dense than Earth's atmosphere. Featured here is a detailed image of the core of the Carina Nebula, a part where both dark and colorful clouds of gas and dust are particularly prominent. The image was captured last month from Siding Spring Observatory in Australia. Although the nebula is predominantly composed of hydrogen gas -- here colored green, the image was...
  • Astronomy Picture of the Day -- Milky Way Over Quiver Tree Forest

    05/15/2016 3:40:02 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | Sunday, May 15, 2016 | (see photo credit)
    Explanation: In front of a famous background of stars and galaxies lies some of Earth's more unusual trees. Known as quiver trees, they are actually succulent aloe plants that can grow to tree-like proportions. The quiver tree name is derived from the historical usefulness of their hollowed branches as dart holders. Occurring primarily in southern Africa, the trees pictured in the above 16-exposure composite are in Quiver Tree Forest located in southern Namibia. Some of the tallest quiver trees in the park are estimated to be about 300 years old. Behind the trees is light from the small town of...
  • Astronomy Picture of the Day -- Falcon 9 and Milky Way

    05/14/2016 1:08:21 PM PDT · by SunkenCiv · 9 replies
    NASA ^ | Saturday, May 14, 2016 | (see photo credit)
    Explanation: On May 6, the after midnight launch of a SpaceX Falcon 9 rocket lit up dark skies over Merritt Island, planet Earth. Its second stage bound for Earth orbit, the rocket's arc seems to be on course for the center of the Milky Way in this pleasing composite image looking toward the southeast. Two consecutive exposures made with camera fixed to a tripod were combined to follow rocket and home galaxy. A 3 minute long exposure at low sensitivity allowed the rocket's first stage burn to trace the bright orange arc and a 30 second exposure at high sensitivity...
  • Astronomy Picture of the Day -- ISS and Mercury Too

    05/14/2016 1:03:04 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | Friday, May 13, 2016 | (see photo credit)
    Explanation: Transits of Mercury are relatively rare. Monday's leisurely 7.5 hour long event was only the 2nd of 14 Mercury transits in the 21st century. If you're willing to travel, transits of the International Space Station can be more frequent though, and much quicker. This sharp video frame composite was taken from a well-chosen location in Philadelphia, USA. It follows the space station, moving from upper right to lower left, as it crossed the Sun's disk in 0.6 seconds. Mercury too is included as the small, round, almost stationary silhouette just below center. In apparent size, the International Space Station...
  • Astronomy Picture of the Day -- A Transit of Mercury

    05/12/2016 4:52:01 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | Thursday, May 12, 2016 | (see photo credit)
    Explanation: On May 9, the diminutive disk of Mercury spent about seven and a half hours crossing in front of the Sun as viewed from the general vicinity of Earth. It was the second of 14 transits of the Solar System's innermost planet in the 21st century. Captured from Fulham, London, England, planet Earth the tiny silhouette shares the enormous solar disk with prominences, filaments, and active regions in this sharp image. But Mercury's round disk (left of center) appears to be the only dark spot, despite the planet-sized sunspots scattered across the Sun. Made with an H-alpha filter that...
  • Astronomy Picture of the Day -- A Mercury Transit Music Video from SDO

    05/11/2016 1:52:06 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | Wednesday, May 11, 2016 | (see photo credit)
    Explanation: What's that small black dot moving across the Sun? Mercury. Possibly the clearest view of Mercury crossing in front of the Sun earlier this week was from Earth orbit. The Solar Dynamics Observatory obtained an uninterrupted vista recording it not only in optical light but also in bands of ultraviolet light. Featured here is a composite movie of the crossing set to music. Although the event might prove successful scientifically for better determining components of Mercury' ultra-thin atmosphere, the event surely proved successful culturally by involving people throughout the world in observing a rare astronomical phenomenon. Many spectacular images...
  • Astronomy Picture of the Day -- Saturn and Mars visit Milky Way Star Clouds

    05/10/2016 4:57:55 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | Tuesday, May 10, 2016 | (see photo credit)
    Explanation: Planets, stars, nebulas and a galaxy -- this impressive image has them all. Closest to home are the two planets Mars (right) and Saturn (center), visible as the two bright orange spots in the upper half of the featured image. On the central right are the colorful Rho Ophiuchus star clouds featuring the bright orange star Antares lined up below Mars. These interstellar clouds contain both red emission nebulas and blue reflection nebulas. At the top right of the image is the Blue Horsehead reflection nebula. On the lower left are many dark absorption nebulas that extend from the...
  • Astronomy Picture of the Day -- Webb Telescope Mirror Rises after Assembly

    05/10/2016 4:54:25 AM PDT · by SunkenCiv · 10 replies
    NASA ^ | Monday, May 09, 2016 | (see photo credit)
    Explanation: Move over Hubble -- here comes the James Webb Space Telescope (JWST). JWST promises to be the new most powerful telescope in space. In the last month, the 18-segment gold-plated primary mirror for JWST was unveiled. In the featured time-lapse video taken last week, the 6.5-meter diameter mirror was raised to a vertical position. The dramatic 30-second sequence shows NASA engineers monitoring the test as room lights glint brightly off the mirror's highly reflective surface. The beryllium mirrors have been coated with a thin film of gold to make them more reflective to infrared light. The science goals of...
  • Astronomy Picture of the Day -- Mercury's Transit: An Unusual Spot on the Sun

    05/10/2016 4:51:35 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | Sunday, May 08, 2016 | (see photo credit)
    Explanation: What's that dot on the Sun? If you look closely, it is almost perfectly round. The dot is the result of an unusual type of solar eclipse that occurred in 2006. Usually it is the Earth's Moon that eclipses the Sun. This time, the planet Mercury took a turn. Like the approach to New Moon before a solar eclipse, the phase of Mercury became a continually thinner crescent as the planet progressed toward an alignment with the Sun. Eventually the phase of Mercury dropped to zero and the dark spot of Mercury crossed our parent star. The situation could...
  • Astronomy Picture of the Day -- Three Worlds for TRAPPIST-1

    05/07/2016 5:39:19 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | Saturday, May 07, 2016 | (see photo credit)
    Explanation: Three new found worlds orbit the ultracool dwarf star TRAPPIST-1, a mere 40 light-years away. Their transits were first detected by the Belgian robotic TRAnsiting Planets and Planetesimals Small Telescope, TRAPPIST, at ESO's La Silla Observatory in Chile. The newly discovered exoplanets are all similar in size to Earth. Because they orbit very close to their faint, tiny star they could also have regions where surface temperatures allow for the presence of liquid water, a key ingredient for life. Their tantalizing proximity to Earth makes them prime candidates for future telescopic explorations of the atmospheres of these potentially habitable...
  • Astronomy Picture of the Day -- NGC 7023: The Iris Nebula

    05/06/2016 5:51:52 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | Friday, May 06, 2016 | (see photo credit)
    Explanation: These cosmic clouds have blossomed 1,300 light-years away, in the fertile starfields of the constellation Cepheus. Called the Iris Nebula, NGC 7023 is not the only nebula to evoke the imagery of flowers, though. Still, this deep telescopic image shows off the Iris Nebula's range of colors and symmetries, embedded in surrounding fields of interstellar dust. Within the Iris itself, dusty nebular material surrounds a hot, young star. The dominant color of the brighter reflection nebula is blue, characteristic of dust grains reflecting starlight. Central filaments of the reflection nebula glow with a faint reddish photoluminesence as some dust...
  • Astronomy Picture of the Day -- The SONG and the Hunter

    05/05/2016 6:49:49 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | Thursday, May 05, 2016 | (see photo credit)
    Explanation: Near first quarter, the Moon in March lights this snowy, rugged landscape, a view across the top of Tenerife toward La Palma in the Canary Islands Spanish archipelago. The large Teide volcano, the highest point in Spain, looms over the horizon. Shining above are familiar bright stars of Orion, the Hunter. Adding to the dreamlike scene is the 1 meter diameter prototype telescope of the global network project called the Stellar Observations Network Group or SONG. The SONG's fully robotic observatory was captured during the 30 second exposure while the observatory dome, with slit open, was rotated across the...
  • Astronomy Picture of the Day -- A Mercury Transit Sequence

    05/03/2016 11:41:56 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | Wednesday, May 04, 2016 | (see photo credit)
    Explanation: This coming Monday, Mercury will cross the face of the Sun, as seen from Earth. Called a transit, the last time this happened was in 2006. Because the plane of Mercury's orbit is not exactly coincident with the plane of Earth's orbit, Mercury usually appears to pass over or under the Sun. The above time-lapse sequence, superimposed on a single frame, was taken from a balcony in Belgium shows the entire transit of 2003 May 7. The solar crossing lasted over five hours, so that the above 23 images were taken roughly 15 minutes apart. The north pole of...
  • Astronomy Picture of the Day -- Aurora over Sweden

    05/03/2016 12:44:34 AM PDT · by SunkenCiv · 8 replies
    NASA ^ | Tuesday, May 03, 2016 | (see photo credit)
    Explanation: It was bright and green and stretched across the sky. This striking aurora display was captured last month just outside of Östersund, Sweden. Six photographic fields were merged to create the featured panorama spanning almost 180 degrees. Particularly striking aspects of this aurora include its sweeping arc-like shape and its stark definition. Lake Storsjön is seen in the foreground, while several familiar constellations and the star Polaris are visible through the aurora, far in the background. Coincidently, the aurora appears to avoid the Moon visible on the lower left. The aurora appeared a day after a large hole opened...
  • Astronomy Picture of the Day -- Crossing Mars

    05/03/2016 12:36:30 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | Monday, May 02, 2016 | (see photo credit)
    Explanation: Where is NASA's rover Curiosity going on Mars? Its geographical goals are on the slopes of Mount Sharp, whose peak is seen in the background on the right. A key scientific goal, however, remains to better assess when and where conditions on Mars were once suitable for life, in particular microbial life. To further this goal, Curiosity was directed to cross the rugged terrain of Nautkluft Plateau, visible in the featured image on the foreground left. Curiosity is crossing toward smoother uphill sites with rocks containing hematite and sulfates, sites that could give the rolling rover new clues on...
  • Astronomy Picture of the Day -- Contemplating the Sun

    05/03/2016 12:35:51 AM PDT · by SunkenCiv · 5 replies
    NASA ^ | Sunday, May 01, 2016 | (see photo credit)
    Explanation: Have you contemplated your home star recently? Featured here, a Sun partially eclipsed on the top left by the Moon is also seen eclipsed by earthlings contemplating the eclipse below. The spectacular menagerie of silhouettes was taken in 2012 from the Glen Canyon National Recreation Area near Page, Arizona, USA, where park rangers and astronomers expounded on the unusual event to interested gatherers. Also faintly visible on the Sun's disk, just to the lower right of the dark Moon's disk, is a group of sunspots. Although a partial solar eclipse by the Moon is indeed a good chance to...
  • Astronomy Picture of the Day -- Moon over Makemake

    04/30/2016 2:03:40 PM PDT · by SunkenCiv · 8 replies
    NASA ^ | Saturday, April 30, 2016 | (see photo credit)
    Explanation: Makemake, second brightest dwarf planet of the Kuiper belt, has a moon. Nicknamed MK2, Makemake's moon reflects sunlight with a charcoal-dark surface, about 1,300 times fainter than its parent body. Still, it was spotted in Hubble Space Telescope observations intended to search for faint companions with the same technique used to find the small satellites of Pluto. Just as for Pluto and its satellites, further observations of Makemake and orbiting moon will measure the system's mass and density and allow a broader understanding of the distant worlds. About 160 kilometers (100 miles) across compared to Makemake's 1,400 kilometer diameter,...
  • Astronomy Picture of the Day -- Fermi's Gamma-ray Moon

    04/29/2016 5:07:09 AM PDT · by SunkenCiv · 20 replies
    NASA ^ | Friday, April 29, 2016 | (see photo credit)
    Explanation: If you could only see gamma-rays, photons with up to a billion or more times the energy of visible light, the Moon would be brighter than the Sun! That startling notion underlies this novel image of the Moon, based on data collected by the Fermi Gamma-ray Space Telescope's Large Area Telescope (LAT) instrument during its first seven years of operation (2008-2015). Fermi's gamma-ray vision doesn't distinguish details on the lunar surface, but a gamma-ray glow consistent with the Moon's size and position is clearly found at the center of the false color map. The brightest pixels correspond to the...
  • Astronomy Picture of the Day -- A Dust Angel Nebula

    04/28/2016 4:21:53 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | Thursday, April 28, 2016 | (see photo credit)
    Explanation: The combined light of stars along the Milky Way are reflected by these cosmic dust clouds that soar some 300 light-years or so above the plane of our galaxy. Dubbed the Angel Nebula, the faint apparition is part of an expansive complex of dim and relatively unexplored, diffuse molecular clouds. Commonly found at high galactic latitudes, the dusty galactic cirrus can be traced over large regions toward the North and South Galactic poles. Along with the refection of starlight, studies indicate the dust clouds produce a faint reddish luminescence, as interstellar dust grains convert invisible ultraviolet radiation to visible...
  • Astronomy Picture of the Day -- Omega Centauri: The Brightest Globular Star Cluster

    04/27/2016 4:48:35 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | Wednesday, April 27, 2016 | (see photo credit)
    Explanation: This huge ball of stars predates our Sun. Long before humankind evolved, before dinosaurs roamed, and even before our Earth existed, ancient globs of stars condensed and orbited a young Milky Way Galaxy. Of the 200 or so globular clusters that survive today, Omega Centauri is the largest, containing over ten million stars. Omega Centauri is also the brightest globular cluster, at apparent visual magnitude 3.9 it is visible to southern observers with the unaided eye. Cataloged as NGC 5139, Omega Centauri is about 18,000 light-years away and 150 light-years in diameter. Unlike many other globular clusters, the stars...
  • Astronomy Picture of the Day -- NGC 6872: A Stretched Spiral Galaxy

    04/26/2016 11:24:02 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | Tuesday, April 26, 2016 | (see photo credit)
    Explanation: What makes this spiral galaxy so long? Measuring over 700,000 light years across from top to bottom, NGC 6872, also known as the Condor galaxy, is one of the most elongated barred spiral galaxies known. The galaxy's protracted shape likely results from its continuing collision with the smaller galaxy IC 4970, visible just above center. Of particular interest is NGC 6872's spiral arm on the upper left, as pictured here, which exhibits an unusually high amount of blue star forming regions. The light we see today left these colliding giants before the days of the dinosaurs, about 300 million...
  • Astronomy Picture of the Day -- Supernova Remnant Simeis 147: The Spaghetti Nebula

    04/26/2016 11:21:23 AM PDT · by SunkenCiv · 6 replies
    NASA ^ | Monday, April 25, 2016 | (see photo credit)
    Explanation: It's easy to get lost following the intricate strands of the Spaghetti Nebula. A supernova remnant cataloged as Simeis 147 and Sh2-240, the glowing gas filaments cover nearly 3 degrees -- 6 full moons -- on the sky. That's about 150 light-years at the stellar debris cloud's estimated distance of 3,000 light-years. This sharp composite includes image data taken through a narrow-band filter to highlight emission from hydrogen atoms tracing the shocked, glowing gas. The supernova remnant has an estimated age of about 40,000 years, meaning light from the massive stellar explosion first reached Earth about 40,000 years ago....
  • Astronomy Picture of the Day -- M16: Pillars of Star Creation

    04/24/2016 7:22:41 AM PDT · by SunkenCiv · 12 replies
    NASA ^ | Sunday, April 24, 2016 | (see photo credit)
    Explanation: Newborn stars are forming in the Eagle Nebula. This image, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away. The pillars of creation were imaged...
  • Astronomy Picture of the Day -- Milky Way in Moonlight

    04/23/2016 11:47:17 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | Saturday, April 23, 2016 | (see photo credit)
    Explanation: A waning crescent moon, early morning twilight, and Al Hamra's city lights on the horizon can't hide the central Milky Way in this skyscape from planet Earth. Captured in a single exposure, the dreamlike scene looks southward across the region's grand canyon from Jabal Shams (Sun Mountain), near the highest peak in Oman, on the Arabian Peninsula. Mist, moonlight, and shadows still play along the steep canyon walls. Dark rifts along the luminous band of the Milky Way are the galaxy's cosmic dust clouds. Typically hundreds of light-years distant, they obscure starlight along the galactic plane, viewed edge-on from...
  • Astronomy Picture of the Day -- NGC 7635: The Bubble Nebula

    04/22/2016 6:42:44 AM PDT · by SunkenCiv · 3 replies
    NASA ^ | Friday, April 22, 2016 | (see photo credit)
    Explanation: Blown by the wind from a massive star, this interstellar apparition has a surprisingly familiar shape. Cataloged as NGC 7635, it is also known simply as The Bubble Nebula. Although it looks delicate, the 7 light-year diameter bubble offers evidence of violent processes at work. Above and left of the Bubble's center is a hot, O-type star, several hundred thousand times more luminous and around 45 times more massive than the Sun. A fierce stellar wind and intense radiation from that star has blasted out the structure of glowing gas against denser material in a surrounding molecular cloud. The...
  • Astronomy Picture of the Day -- The Comet, the Owl, and the Galaxy

    04/21/2016 1:45:26 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | Thursday, April 21, 2016 | (see photo credit)
    Explanation: Comet C/2014 S2 (PanSTARRS) poses for a Messier moment in this telescopic snapshot from April 18. In fact it shares the 1.5 degree wide field-of-view with two well-known entries in the 18th century comet-hunting astronomer's famous catalog. Outward bound and sweeping through northern skies just below the Big Dipper, the fading visitor to the inner Solar System was about 18 light-minutes from our fair planet. Dusty, edge-on spiral galaxy Messier 108 (upper right) is more like 45 million light-years away. A planetary nebula with an aging but intensely hot central star, the owlish Messier 97 is only about 12...
  • Astronomy Picture of the Day -- Galaxy Einstein Ring

    04/21/2016 1:43:17 PM PDT · by SunkenCiv · 5 replies
    NASA ^ | Wednesday, April 20, 2016 | (see photo credit)
    Explanation: Can one galaxy hide behind another? Not in the case of SDP.81. Here the foreground galaxy, shown in blue in an image taken by the Hubble Space Telescope, acts like a huge gravitational lens, pulling light from a background galaxy, shown in red in an image taken in radio waves by the Atacama Large Millimeter Array (ALMA), around it, keeping it visible. The alignment is so precise that the distant galaxy is distorted into part of a ring around the foreground galaxy, a formation known as an Einstein ring. Detailed analysis of the gravitational lens distortions indicate that a...
  • Astronomy Picture of the Day -- Andromeda Rising over Colombia

    04/19/2016 5:16:44 AM PDT · by SunkenCiv · 15 replies
    NASA ^ | Tuesday, April 19, 2016 | (see photo credit)
    Explanation: What’s that rising over the hill? A galaxy. Never having seen a galaxy themselves, three friends of an industrious astrophotographer experienced an exhilarating night sky firsthand that featured not only the band of our Milky Way galaxy but also Milky Way's neighbor -- the Andromeda galaxy. Capturing the scene required careful pre-shot planning including finding a good site, waiting for good weather, balancing relative angular sizes with a zoom lens, managing ground lighting, and minimizing atmospheric light absorption. The calculated shot therefore placed the friends on a hill about 250 meters away and about 50 meters up. The featured...
  • Astronomy Picture of the Day -- The International Space Station over Earth

    04/18/2016 1:11:17 PM PDT · by SunkenCiv · 18 replies
    NASA ^ | Monday, April 18, 2016 | (see photo credit)
    Explanation: The International Space Station is the largest object ever constructed by humans in space. The station perimeter extends over roughly the area of a football field, although only a small fraction of this is composed of modules habitable by humans. The station is so large that it could not be launched all at once -- it continues to be built piecemeal. To function, the ISS needs huge trusses, some over 15 meters long and with masses over 10,000 kilograms, to keep it rigid and to route electricity and liquid coolants. Pictured above, the immense space station was photographed from...
  • Astronomy Picture of the Day -- Asperatus Clouds Over New Zealand

    04/17/2016 4:59:47 PM PDT · by SunkenCiv · 25 replies
    NASA ^ | Sunday, April 17, 2016 | (see photo credit)
    Explanation: What kind of clouds are these? Although their cause is presently unknown, such unusual atmospheric structures, as menacing as they might seem, do not appear to be harbingers of meteorological doom. Known informally as Undulatus asperatus clouds, they can be stunning in appearance, unusual in occurrence, are relatively unstudied, and have even been suggested as a new type of cloud. Whereas most low cloud decks are flat bottomed, asperatus clouds appear to have significant vertical structure underneath. Speculation therefore holds that asperatus clouds might be related to lenticular clouds that form near mountains, or mammatus clouds associated with thunderstorms,...
  • Astronomy Picture of the Day -- Heliopause Electrostatic Rapid Transit System

    04/16/2016 12:00:03 PM PDT · by SunkenCiv · 14 replies
    NASA ^ | Saturday, April 16, 2016 | (see photo credit)
    Explanation: Want to take a fast trip to the edge of the Solar System? Consider a ride on a Heliopause Electrostatic Rapid Transit System (HERTS). The concept is currently being tested and it might take only 10 to 15 years to make the trip of over 100 Astronomical Units (15 billion kilometers). That's fast compared to the 35 years it took Voyager 1, presently humanity's most distant spacecraft, to approach the heliopause or outer boundary of the influence of the solar wind. HERTS would use an advanced electric solar sail that works by extending multiple, 20 kilometer or so long,...
  • Astronomy Picture of the Day -- Mercury and Crescent Moon Set

    04/16/2016 11:57:44 AM PDT · by SunkenCiv · 4 replies
    NASA ^ | Friday, April 15, 2016 | (see photo credit)
    Explanation: Innermost planet Mercury and a thin crescent Moon are never found far from the Sun in planet Earth's skies. Taken near dusk on April 8, this colorful evening skyscape shows them both setting toward the western horizon just after the Sun. The broad Tagus River and city lights of Lisbon, Portugal run through the foreground under the serene twilight sky. Near perigee or closest approach to Earth, the Moon's bright, slender crescent represents about 3 percent of the lunar disk in sunlight. Of course as seen from the Moon, a nearly full Earth would light up the lunar night,...
  • Astronomy Picture of the Day -- Full Venus and Crescent Moon Rise

    04/14/2016 6:02:26 AM PDT · by SunkenCiv · 1 replies
    NASA ^ | Thursday, April 14, 2016 | (see photo credit)
    Explanation: Inner planet Venus and a thin crescent Moon are never found far from the Sun in planet Earth's skies. Taken near dawn on April 6, this timelapse composite shows them both rising just before the Sun. The mountaintop Teide Observatory domes on the fortunate island of Tenerife appear in silhouette against the twilight. In fact, the series of telephoto exposures follows the occultation of Venus by the Moon in three frames. Far from Earth in its orbit and in a nearly full phase, Venus was 96 percent illuminated. Near perigee or closest approach to Earth, the Moon's slender crescent...
  • Astronomy Picture of the Day -- Orion in Red and Blue

    04/13/2016 2:15:27 PM PDT · by SunkenCiv · 3 replies
    NASA ^ | Wednesday, April 13, 2016 | (see photo credit)
    Explanation: When did Orion become so flashy? This colorful rendition of part of the constellation of Orion comes from red light emitted by hydrogen and sulfur (SII), and blue-green light emitted by oxygen (OIII). Hues on the featured image were then digitally reassigned to be indicative of their elemental origins -- but also striking to the human eye. The breathtaking composite was painstakingly composed from hundreds of images which took nearly 200 hours to collect. Pictured, Barnard's Loop, across the image bottom, appears to cradle interstellar constructs including the intricate Orion Nebula seen just right of center. The Flame Nebula...
  • Astronomy Picture of the Day -- Combined Solar Eclipse Corona from Earth and Space

    04/12/2016 7:33:57 AM PDT · by SunkenCiv · 11 replies
    NASA ^ | Tuesday, April 12, 2016 | (see photo credit)
    Explanation: Sometimes, a total eclipse is a good time to eye the Sun. Taking advantage of an unusual juxtaposition of Earth, Moon and Sun, the featured image depicts the total solar eclipse that occurred last month as it appeared -- nearly simultaneously -- from both Earth and space. The innermost image shows the total eclipse from the ground, with the central pupil created by the bright Sun covered by a comparatively dark Moon. Surrounding the blocked solar disk is the tenuous corona of Sun imaged in white light, easily visible from the ground only during an eclipse. Normally, this corona...
  • Astronomy Picture of the Day -- The Comet and the Star Cluster

    04/11/2016 5:37:23 AM PDT · by SunkenCiv · 2 replies
    NASA ^ | Monday, April 11, 2016 | (see photo credit)
    Explanation: Image Credit & Copyright: Comet Linear has become unexpectedly bright. The comet, discovered in 2000, underwent a 100-fold outburst just a week before it passed a mere 14 lunar distances from Earth late last month. The comet was captured here last week at about magnitude 6 -- just bright enough to be seen by the unaided eye -- passing in front of the distant globular star cluster M14. Comet 252/P LINEAR is one of a rare group of comets that vacillate between the Earth and Jupiter every 5 years. How the comet will evolve from here is unknown, but...
  • Astronomy Picture of the Day -- Cassini Approaches Saturn

    04/10/2016 12:31:18 PM PDT · by SunkenCiv · 11 replies
    NASA ^ | Sunday, April 10, 2016 | (see photo credit)
    Explanation: Cassini, a robot spacecraft launched in 1997 by NASA, became close enough in 2002 to resolve many rings and moons of its destination planet: Saturn. At that time, Cassini snapped several images during an engineering test. Several of those images were combined into the contrast-enhanced color composite featured here. Saturn's rings and cloud-tops are visible toward the image bottom, while Titan, its largest moon, is visible as the speck toward the top. When arriving at Saturn in July 2004, the Cassini orbiter began to circle and study the Saturnian system. A highlight was when Cassini launched the Huygens probe...
  • Astronomy Picture of the Day -- A Green Flash of Spring

    04/09/2016 4:40:45 AM PDT · by SunkenCiv · 9 replies
    NASA ^ | Saturday, April 09, 2016 | (see photo credit)
    Explanation: Taken on March 20 from the top of Haleakala on the isle of Maui, planet Earth, the first sunrise of northern spring is pictured in this vacation snapshot. The telephoto view from the volcanic caldera above a sea of clouds also captures an elusive green flash near the Sun's upper limb. Atmospheric layers with sharp temperature changes cause the colorful flash as the Sun rises behind a distant cloud bank. Refraction along sight lines through the layers creates multiple distorted images of the Sun, and for a moment, can visibly deflect shorter wavelength green light.