http://www.zorg.ch/forum.php Zorg RSS Feed de-DE Thu, 09 Sep 2010 11:07:04 http://www.zorg.ch/gallery.php?show=pic&picID=13581&parent_id=13581#112756 Thu, 09 Sep 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13581&parent_id=13581#112756 NGC 4911: Spiral Diving into a Dense Cluster

Explanation: Why are there faint rings around this spiral galaxy? Possibly because the galaxy, NGC 4911, is being pulled at by its neighbors as it ...]]> NGC 4911: Spiral Diving into a Dense Cluster

Explanation: Why are there faint rings around this spiral galaxy? Possibly because the galaxy, NGC 4911, is being pulled at by its neighbors as it falls into the enormous Coma Cluster of Galaxies. If NGC 4911 ends up like most of the galaxies in the central Coma cluster, it will become a yellowish elliptical galaxy, losing not only its outer layers, but dust, gas, and its cadre of surrounding satellite galaxies as well. Currently, however, this process is just beginning. Visible in the above deep image from the Hubble Space Telescope are NGC 4911's bright nucleus, distorted spiral arms laced with dark dust, clusters of recently formed stars, unusual faint outer rings, dwarf companion galaxies, and even faint globular clusters of stars. Far in the distance many unassociated galaxies from the early universe are visible, some even through NGC 4911 itself. The Coma Cluster contains over 1,000 galaxies making it among the most massive objects known. NGC 4911 can be found to the lower left of the great cluster's center. Poll: Which of last week's APODs should be the APOW?

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13580&parent_id=13580#112755 Wed, 08 Sep 2010 00:00:06 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13580&parent_id=13580#112755 Space Shuttle Tribute Poster: Endeavour

Explanation: They are some of the most complex machines ever built. From a standing start they can launch a most complex machines ever built. From a standing start they can launch a school- bus sized object up so high and moving so fast that it won't fall back down. They have launched numerous revolutionary satellites that enable humans to communicate across the globe, to better understand Earth's atmosphere, and to peer into the distance universe. They are NASA's Space Shuttles, and NASA has recently released large digital posters to honor them. While the inaugural flight was in 1981, the shuttle fleet is aging and is now nearing retirement. Pictured above, the space shuttle Endeavour is shown rising to orbit, with patches for each of its missions shown in a spiral. Endeavour was named for the HMS Endeavour, a British research ship that explored the south Pacific Ocean in the 1700s, depicted on the lower right. On the upper left are panoramic windows delivered by Endeavour to the International Space Station earlier this year. In the background near the top is the NGC 602 nebula as imaged by the Hubble Space Telescope, which was serviced by Endeavour in 1993. Posters for all of the shuttles, including Atlantis, Challenger, Columbia, Discovery, Endeavour are available.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13579&parent_id=13579#112754 Tue, 07 Sep 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13579&parent_id=13579#112754 A Laser Strike at the Galactic Center

Explanation: Why are these people shooting a powerful laser into the center of our Galaxy? Fortunately, this is not meant to be the first step in a Galactic A Laser Strike at the Galactic Center

Explanation: Why are these people shooting a powerful laser into the center of our Galaxy? Fortunately, this is not meant to be the first step in a Galactic war. Rather, astronomers at the Very Large Telescope (VLT) site in Chile are trying to measure the distortions of Earth's ever changing atmosphere. Constant imaging of high-altitude atoms excited by the laser -- which appear like an artificial star -- allow astronomers to instantly measure atmospheric blurring. This information is fed back to a VLT telescope mirror which is then slightly deformed to minimize this blurring. In this case, a VLT was observing our Galaxy's center, and so Earth's atmospheric blurring in that direction was needed. As for inter-galaxy warfare, when viewed from our Galaxy's center, no casualties are expected. In fact, the light from this powerful laser would combine with light from our Sun to together appear only as bright as a faint and distant star.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13578&parent_id=13578#112753 Mon, 06 Sep 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13578&parent_id=13578#112753 GRO J1655-40: Evidence for a Spinning Black Hole

Explanation: In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Stu...]]> GRO J1655-40: Evidence for a Spinning Black Hole

Explanation: In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes. The gas surrounding GRO J1655-40, for example, has been found to display an unusual flickering at a rate of 450 times a second. Given a previous mass estimate for the central object of seven times the mass of our Sun, the rate of the fast flickering can be explained by a black hole that is rotating very rapidly. What physical mechanisms actually cause the flickering -- and a slower quasi-periodic oscillation (QPO) -- in accretion disks surrounding black holes and neutron stars remains a topic of much research.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13577&parent_id=13577#112752 Sun, 05 Sep 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13577&parent_id=13577#112752 Young Suns of NGC 7129

Explanation: Young suns still lie within dusty NGC 7129, some 3,000 light-years away toward the royal within dusty NGC 7129, some 3,000 light-years away toward the royal constellation Cepheus. While these stars are at a relatively tender age, only a few million years old, it is likely that our own Sun formed in a similar stellar nursery some five billion years ago. Most noticeable in the sharp, (zoomable) image are the lovely bluish dust clouds that reflect the youthful starlight, but the smaller, deep red crescent shapes are also markers of energetic, young stellar objects. Known as Herbig-Haro objects, their shape and color is characteristic of glowing hydrogen gas shocked by jets streaming away from newborn stars. Ultimately the natal gas and dust in the region will be dispersed, the stars drifting apart as the loose cluster orbits the center of the Galaxy. At the estimated distance of NGC 7129, this telescopic view spans about 40 light-years. Take a short survey about viewing astronomy images on mobile devices.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13576&parent_id=13576#112751 Sat, 04 Sep 2010 00:00:07 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13576&parent_id=13576#112751 The Small Cloud of Magellan

Explanation: Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. ...]]> The Small Cloud of Magellan

Explanation: Portuguese navigator Ferdinand Magellan and his crew had plenty of time to study the southern sky during the first circumnavigation of planet Earth. As a result, two celestial wonders easily visible for southern hemisphere skygazers are known as the Clouds of Magellan. These cosmic clouds are now understood to be dwarf irregular galaxies, satellites of our larger spiral Milky Way Galaxy. The Small Magellanic Cloud actually spans 15,000 light-years or so and contains several hundred million stars. About 210,000 light-years away in the constellation Tucana, it is more distant than other known Milky Way satellite galaxies, including the Canis Major and Sagittarius Dwarf galaxies and the Large Magellanic Cloud. This sharp image also includes two foreground globular star clusters NGC 362 (bottom right) and 47 Tucanae. Spectacular 47 Tucanae is a mere 13,000 light-years away and seen here to the left of the Small Magellanic Cloud. Take a short survey about viewing astronomy images on mobile devices.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13575&parent_id=13575#112750 Fri, 03 Sep 2010 00:00:04 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13575&parent_id=13575#112750 The Bubble Nebula

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 s...]]> The Bubble Nebula

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 10 light-year diameter bubble offers evidence of violent processes at work. Above and right of the Bubble's center is a hot, O-type star, several hundred thousand times more luminous and approximately 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 intriguing Bubble Nebula lies a mere 11,000 light-years away toward the boastful constellation Cassiopeia. A false-color Hubble palette was used to create this sharp image and shows emission from sulfur, hydrogen, and oxygen atoms in red, green, and blue hues. The image data was recorded using a small telescope under clear, steady skies, from Mount Wilson Observatory. Battle of the APODs (Poll): Which APOD should be last week's APOW?

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13574&parent_id=13574#112748 Thu, 02 Sep 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13574&parent_id=13574#112748 Earth and Moon from MESSENGER

Explanation: What does Earth look like from the planet Mercury? The robotic spacecraft MESSENGER found out as it looked toward the MESSENGER found out as it looked toward the Earth during its closest approach to the Sun about three months ago. The Earth and Moon are visible as the double spot on the lower left of the above image. Now MESSENGER was not at Mercury when it took the above image, but at a location from which the view would be similar. From Mercury, both the Earth and its comparatively large moon will always appear as small circles of reflected sunlight and will never show a crescent phase. MESSENGER has zipped right by Mercury three times since being launched in 2004, and is scheduled to enter orbit around the innermost planet in March of 2011. New Mirror: APOD available in Persian from Iran.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13573&parent_id=13573#112747 Wed, 01 Sep 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13573&parent_id=13573#112747 The Annotated Galactic Center

Explanation: The sky toward the center of our Galaxy is filled with a wide variety of celestial wonder...]]> The Annotated Galactic Center

Explanation: The sky toward the center of our Galaxy is filled with a wide variety of celestial wonders, many of which are visible from a dark location with common binoculars. Constellations near the Galactic Center include Sagittarius, Libra, Scorpius, Scutum, and Ophiuchus. Nebulas include Messier objects M8, M16, M20, as well as the Pipe and Cat's Paw nebulas. Visible open star clusters include M6, M7, M21, M23, M24, and M25, while globular star cluster M22 is also visible. A hole in the dust toward the Galactic Center reveals a bright region filled with distant stars known as Baade's Window, which is visible between M7 and M8. Moving your cursor over the above image the will bring up an un-annotated version. Poll: Which images would you select for future APODs?

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13572&parent_id=13572#112744 Tue, 31 Aug 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13572&parent_id=13572#112744 Comanche Outcrop on Mars Indicates Hospitable Past

Explanation: Could life once have survived on Mars? Today, neither animal nor plant life from ...]]> Comanche Outcrop on Mars Indicates Hospitable Past

Explanation: Could life once have survived on Mars? Today, neither animal nor plant life from Earth could survive for very long on Mars because at least one key ingredient -- liquid water -- is essentially absent on the red planet's rusty surface. Although evidence from the martian rovers indicates that long ago Mars might once have had liquid water on its surface, that water might also have been too acidic for familiar life forms to thrive. Recently, however, a newly detailed analysis of an unusual outcropping of rock and soil chanced upon in 2005 by the robotic Spirit rover has uncovered a clue indicating that not all of Mars was always so acidic. The mound in question, dubbed Comanche Outcrop and visible near the top of the above image, appears to contain unusually high concentrations of elements such as magnesium iron carbonate. The above image is shown in colors exaggerated to highlight the differences in composition. Since these carbonates dissolve in acid, the persistence of these mounds indicates that water perhaps less acidic and more favorable for life might have once flowed across Mars. More detailed analyses and searches for other signs will surely continue. Teachers & Students: Take an online, textbook-free, video class on Introductory Astronomy for free.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13571&parent_id=13571#112742 Mon, 30 Aug 2010 00:00:04 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13571&parent_id=13571#112742 The Local Fluff

Explanation: The stars are not alone. In the disk of our Milky Way Galaxy about 10 percent of visible matter is in the form of gas, called the Milky Way Galaxy about 10 percent of visible matter is in the form of gas, called the interstellar medium (ISM). The ISM is not uniform, and shows patchiness even near our Sun. It can be quite difficult to detect the local ISM because it is so tenuous and emits so little light. This mostly hydrogen gas, however, absorbs some very specific colors that can be detected in the light of the nearest stars. A working map of the local ISM within 10 light-years based on recent observations is shown above. These observations show that our Sun is moving through a Local Interstellar Cloud as this cloud flows outwards from the Scorpius-Centaurus Association star forming region. Our Sun may exit the Local Interstellar Cloud, also called the Local Fluff, during the next 10,000 years. Much remains unknown about the local ISM, including details of its distribution, its origin, and how it affects the Sun and the Earth.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13570&parent_id=13570#112739 Sun, 29 Aug 2010 00:00:04 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13570&parent_id=13570#112739 Hole in the Sun

Explanation: This ominous, dark shape sprawling across the face of the Sun is a coronal hole -- a low density region extending above the surface where the solar magnetic field open...]]> Hole in the Sun

Explanation: This ominous, dark shape sprawling across the face of the Sun is a coronal hole -- a low density region extending above the surface where the solar magnetic field opens freely into interplanetary space. Studied extensively from space since the 1960s in ultraviolet and x-ray light, coronal holes are known to be the source of the high-speed solar wind, atoms and electrons which flow outward along the open magnetic field lines. During periods of low activity, coronal holes typically cover regions just above the Sun's poles. But this extensive coronal hole dominated the Sun's northern hemisphere earlier this week, captured here in extreme ultraviolet light by cameras onboard the Solar Dynamics Observatory. The solar wind streaming from this coronal hole triggered auroral displays on planet Earth.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13569&parent_id=13569#112736 Sat, 28 Aug 2010 00:00:07 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13569&parent_id=13569#112736 Brighter Than Mars

Explanation: Even though you may have just read an email claiming Mars will be incredibly bright tonight, the brightest star on the horizon is not Mars. F...]]> Brighter Than Mars

Explanation: Even though you may have just read an email claiming Mars will be incredibly bright tonight, the brightest star on the horizon is not Mars. From central Iran on August 24th, the brightest star in this twilight desert skyview is Venus, aka the Evening Star. But a bright Mars is in the picture, just above and right of more brilliant Venus. Despite claims in the internet's annually returning Mars Hoax that Mars will be as big and bright as the Full Moon, this celestial scenario is very similar to the western sky you can see tonight. Along with Mars, the still beautiful vista includes Spica, alpha star of the constellation Virgo, above and left of Venus. Farther right of Venus, Saturn peeks through the sunset's fading glow just above the clouds. Near the opposite horizon, the Full Moon illuminating the desert is about 400,000 times brighter than Mars. Note: APOD tweets are available over Twitter.

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13568&parent_id=13568#112735 Fri, 27 Aug 2010 00:00:04 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13568&parent_id=13568#112735 M27: Not a Comet

Explanation: While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were de...]]> M27: Not a Comet

Explanation: While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. This is number 27 on his now famous not-a-comet list. In fact, 21st century astronomers would identify it as a planetary nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is an excellent example of a gaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula. This impressive color composite highlights details within the well-studied central region and fainter, seldom imaged features in the nebula's outer halo. It includes narrowband images recorded using filters sensitive to emission from oxygen atoms, shown in blue-green hues, and hydrogen atoms in red. Poll: Which of last week's APODs should be the APOW?

Credit & Copyright]]> http://www.zorg.ch/gallery.php?show=pic&picID=13566&parent_id=13566#112732 Wed, 25 Aug 2010 00:00:05 [z]Barbara Harris http://www.zorg.ch/gallery.php?show=pic&picID=13566&parent_id=13566#112732 Galaxy Cluster Abell 1689 Magnifies the Dark Universe

Explanation: What's the matter with this cluster of galaxies? To find out what forms matter takes in the Abell 1689 cluster requires not...]]> Galaxy Cluster Abell 1689 Magnifies the Dark Universe

Explanation: What's the matter with this cluster of galaxies? To find out what forms matter takes in the Abell 1689 cluster requires not only deep images from telescopes like the Hubble Space Telescope, but detailed computer modeling as well. To start, almost every fuzzy yellow patch in the above image is an entire galaxy. A close inspection, however, shows that many background galaxies are strangely magnified and distorted into long curving arcs by the gravitational lens deflections of the cluster. Computer analyses of the placement and smoothness of these arcs indicate that in addition to the matter in the galaxies you can see, the cluster must also contain a significant amount of dark matter such as the model digitally superposed in purple. Now Abell 1689 remains enigmatic because the arcs are so numerous and diverse that no single dark matter model has emerged that can explain them all and still remain consistent with dark matter models needed to constrain their motion. Still, the detailed information available from clusters of galaxies like Abell 1689 gives hope that one day full solutions will be found that will not only fully reveal the dark matter in clusters, but also reveal the amounts of dark energy in the universe needed to lie along the line of sight to the distant arcs. Students and Teachers: Free video online Astro 101 course

Credit & Copyright]]>