Astronomia => Notícias => Tópico iniciado por: ahlberto em Setembro 28, 2008, 05:55:32 pm

Título: APOD DO DIA
Enviado por: ahlberto em Setembro 28, 2008, 05:55:32 pm
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Título: Re: APOD DO DIA
Enviado por: ahlberto em Setembro 30, 2008, 12:51:28 am
A True Image from False Kiva
Credit & Copyright: Wally Pacholka (Astropics.com/TWAN)
Explanation: Is there any place in the world you could see a real sight like this? Yes. Pictured above is single exposure image spectacular near, far, and in between. Diving into the Earth far in the distance is part of the central band of our Milky Way Galaxy, taken with a long duration exposure. Much closer, the planet Jupiter is visible as the bright point just to band's left. Closer still are picturesque buttes and mesas of the Canyonlands National Park in Utah, USA, lit by a crescent moon. In the foreground is a cave housing a stone circle of unknown origin named False Kiva. The cave was briefly lit by flashlight during the long exposure. Astrophotographer Wally Pacholka reports that getting to the cave to take this image was no easy trek. Also, mountain lions were a concern while waiting alone in the dark for just the right exposure.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Setembro 30, 2008, 08:21:55 pm
Planets Ahoy!
Credit & Copyright: Mike Salway (IceInSpace)
Explanation: Can you spot the Solar System's four rocky planets? In the above image taken on September 20, all of them were visible in a single glance, but some of them may be different than you think. Pictured above, the brightest and highest object in the sky is the planet Venus. The object lowest in the sky is the planet Mars, while the object furthest to the left is the planet Mercury. The last remaining point of light is . . . the bright star Spica, which leaves the question -- where is the fourth rocky planet? That would be Earth, specifically part of Australia, visible across the entire bottom of the image.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 01, 2008, 06:53:09 pm
The First Rocket Launch from Cape Canaveral
Credit: GRIN, NASA
Explanation: A new chapter in space flight began on 1950 July with the launch of the first rocket from Cape Canaveral, Florida: the Bumper 2. Shown above, the Bumper 2 was an ambitious two-stage rocket program that topped a V-2 missile base with a WAC Corporal rocket. The upper stage was able to reach then-record altitudes of almost 400 kilometers, higher than even modern Space Shuttles fly today. Launched under the direction of the General Electric Company, the Bumper 2 was used primarily for testing rocket systems and for research on the upper atmosphere. Bumper 2 rockets carried small payloads that allowed them to measure attributes including air temperature and cosmic ray impacts. Seven years later, the Soviet Union launched Sputnik I and Sputnik II, the first satellites into Earth orbit. In response in 1958, 50 years ago today, the US created NASA.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 02, 2008, 05:19:33 pm
NGC 253 Close-Up
Credit: NASA, ESA, J. Dalcanton, B. Williams (Univ. Washington)
Ground-based data: T. Rector (Univ. Alaska, Anchorage), T. Abbott, NOAO/AURA/NSF
Explanation: This dusty island universe is one of the brightest spiral galaxies in the sky. Seen nearly edge-on, NGC 253 lies a mere 13 million light-years away and is the largest member of the Sculptor Group of galaxies, neighbor to our own local galaxy group. The remarkably sharp, close-up view is based on data from the Hubble's Advanced Camera for Surveys (ACS). Beginning on the left near the galaxy's core, the panorama follows filaments of dust, interstellar gas, and even individual stars toward the galaxy's edge at the far right, a magnificent vista spanning nearly 50,000 light-years. The image data are part of ANGST, the ACS Nearby Galaxy Survey Treasury, a program to explore our cosmic backyard.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 03, 2008, 05:04:04 pm
Young Suns of NGC 7129
Credit & Copyright: Bob and Janice Fera (Fera Photography)
Explanation: Young suns still lie 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 about a 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 striking 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.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 04, 2008, 03:33:38 pm
A Solar Prominence Unfurls
Credit: STEREO Project, NASA
Explanation: On September 29, this magnificent eruptive solar prominence lifted away from the Sun's surface, unfurling into space over the course of several hours. Suspended in twisted magnetic fields, the hot plasma structure is many times the size of planet Earth and was captured in this view by the Sun-watching STEREO (Ahead) spacecraft. The image was recorded in extreme ultraviolet light emitted by ionized Helium, an element originally identified in the solar spectrum. Seen against the brilliant solar surface in visible light, such prominences appear as dark filaments because they are relatively cool. But they are bright themselves when viewed against the blackness of space, arcing above the Sun's edge.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 05, 2008, 10:24:34 am
Earth at Night
Credit: C. Mayhew & R. Simmon (NASA/GSFC), NOAA/NGDC, DMSP Digital Archive
Explanation: This is what the Earth looks like at night. Can you find your favorite country or city? Surprisingly, city lights make this task quite possible. Human-made lights highlight particularly developed or populated areas of the Earth's surface, including the seaboards of Europe, the eastern United States, and Japan. Many large cities are located near rivers or oceans so that they can exchange goods cheaply by boat. Particularly dark areas include the central parts of South America, Africa, Asia, and Australia. The above image is actually a composite of hundreds of pictures made by the orbiting DMSP satellites.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 07, 2008, 08:30:30 am
Layers of Red Cliffs on Mars
Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: How did these layers of red cliffs form on Mars? No one is sure. The northern ice cap on Mars is nearly divided into two by a huge division named Chasma Boreale. No similar formation occurs on Earth. Pictured above, several dusty layers leading into this deep chasm are visible. Cliff faces, mostly facing left but still partly visible from above, appear dramatically red. The light areas are likely water ice. The above image spans about one kilometer near the north of Mars, and the elevation drop from right to left is over a kilometer. One hypothesis relates the formation of Chasma Boreale to underlying volcanic activity.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 07, 2008, 03:26:09 pm
Dust Mountains in the Carina Nebula
Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Acknowledgement: N. Smith et al. (JHU)
Explanation: Bright young stars sometimes sculpt picturesque dust mountains soon after being born. Created quite by accident, the energetic light and winds from these massive newborn stars burn away accumulations of dark dust and cool gas in a slow but persistent manner. Such is the case in NGC 3324, a star forming region near the edge of NGC 3372, the energetic and expansive Carina Nebula. Pictured above, in scientifically assigned colors, is only a small part of NGC 3324. The Carina Nebula itself is one of the largest star forming regions known and home to Eta Carinae, one of the most unstable and variable stars known. The above image was created from archived Hubble Space Telescope data in honor of the 10th anniversary of the Hubble Heritage Project. The Hubble Heritage Project has created, so far, nearly 130 visually stunning images.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 08, 2008, 03:33:24 pm
Mercury as Revealed by MESSENGER
Credit: MESSENGER, NASA, JHU APL, CIW
Explanation: The planet Mercury has been known since history has been recorded, but parts of the Solar System's innermost planet have never been seen like this before. Two days ago the robotic MESSENGER spacecraft buzzed past Mercury for the second time and imaged terrain mapped previously only by comparatively crude radar. The above image was recorded as MESSENGER looked back 90 minutes after passing, from an altitude of about 27,000 kilometers. Visible in the above image, among many other newly imaged features, are unusually long rays that appear to run like meridians of longitude out from a young crater near the northern limb. MESSENGER is scheduled to fly past Mercury once more before firing its thrusters to enter orbit in 2011.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 09, 2008, 02:27:47 pm
Massive Stars in NGC 6357
Credit & Copyright: Johannes Schedler (Panther Observatory)
Explanation: Massive Stars lie within NGC 6357, an expansive emission nebula complex some 8,000 light-years away in the tail of the constellation Scorpius. In fact, positioned just below center in this close-up view of NGC 6357, star cluster Pismis 24 includes some of the most massive stars known in the galaxy, stars with over 100 times the mass of the Sun. The nebula's bright central region also contains dusty pillars of molecular gas, likely hiding massive protostars from the prying eyes of optical instruments. Intricate shapes in the nebula are carved by interstellar winds and energetic radiation from the young and newly forming massive stars. This alluring telescopic view spans just under 50 light-years at the estimated distance of NGC 6357.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 10, 2008, 07:02:22 pm
Irregular Galaxy NGC 55
Credit & Copyright: Robert Gendler
Explanation: Irregular galaxy NGC 55 is thought to be similar to the Large Magellanic Cloud (LMC). But while the LMC is about 180,000 light-years away and is a well known satellite of our own Milky Way Galaxy, NGC 55 is more like 6 million light-years distant and is a member of the Sculptor Galaxy Group. Classified as an irregular galaxy, in deep exposures the LMC itself resembles a barred disk galaxy. However, spanning about 50,000 light-years, NGC 55 is seen nearly edge-on, presenting a flattened, narrow profile in contrast with our face-on view of the LMC. Just as large star forming regions create emission nebulae in the LMC, NGC 55 is also seen to be producing new stars. This gorgeous galaxy portrait highlights a bright core, telltale pinkish emission regions, and young blue star clusters in NGC 55.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 11, 2008, 09:36:45 am
Bright Bolide
Credit & Copyright: Howard Edin (Oklahoma City Astronomy Club)
Explanation: On September 30, a spectacular bolide or fireball meteor surprised a group of amateur astronomers enjoying dark night skies over the Oklahoma panhandle's Black Mesa State Park in the Midwestern US. Flashing past familiar constellations Taurus (top) and Orion, the extremely bright meteor was captured by a hillside camera overlooking the 2008 Okie-Tex Star Party. Astronomy enthusiast Howard Edin reports that he was looking in the opposite direction at the time, but saw the whole observing field light up and at first thought someone had turned on their car headlights. So far the sighting of a such a bright bolide meteor, produced as a space rock is vaporized hurtling through Earth's atmosphere, really is a matter of luck. But that could change. Earlier this week the discovery and follow-up tracking of tiny asteroid 2008 TC3 allowed astronomers to predict the time and location of its impact with the atmosphere. While no ground-based sightings of the fireball seem to have been reported, this first ever impact prediction was confirmed by at least some detections of an air burst and bright flash on October 7th over northern Sudan.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 12, 2008, 12:17:26 pm
Spiral Galaxy NGC 3370 from Hubble
Credit: NASA, ESA, Hubble Heritage (STScI/AURA); Acknowledgement: A. Reiss et al. (JHU)
Explanation: Is this what our own Milky Way Galaxy looks like from far away? Similar in size and grand design to our home Galaxy (although without the central bar), spiral galaxy NGC 3370 lies about 100 million light-years away toward the constellation of the Lion (Leo). Recorded above in exquisite detail by the Hubble Space Telescope's Advanced Camera for Surveys, the big, beautiful face-on spiral is not only photogenic, but has proven sharp enough to study individual stars known as Cepheids. These pulsating stars have been used to accurately determine NGC 3370's distance. NGC 3370 was chosen for this study because in 1994 the spiral galaxy was also home to a well studied stellar explosion -- a Type Ia supernova. Combining the known distance to this standard candle supernova, based on the Cepheid measurements, with observations of supernovas at even greater distances, has helped to reveal the size and expansion rate of the entire Universe itself.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 14, 2008, 08:11:33 am
Cassini Passes Through Ice Plumes of Enceladus
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation: What telling impurities taint the ice plumes of Enceladus? To help answer this question, the robotic Cassini spacecraft dove last week to within 30 kilometers of Saturn's ice-plume emitting moon. At this closest-ever approach, Cassini attempted to sniff and obtain chemical data on particles ejected from Enceladus' regular surface, while at other times Cassini flew right through -- and sampled -- ice geysers directly. Searches in the data for impurity clues in the water-ice dominated plumes and surface ejecta are progressing. Although the main purpose of this flyby was particle analysis, several interesting images are emerging. Visible in the above image, for example, is an unusual gray sheen running vertically up the image center that might be water vapor escaping from surface canyons. Other notable features visible above include vast plains of craterless icy grooves, the day-night terminator across the image left, and an area near the top comparatively rich in craters. Cassini is scheduled to buzz by Enceladus in an imaging run near the end of this month.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 15, 2008, 08:49:34 am
Camera Orion
Credit & Copyright: John Gauvreau
Explanation: Orion, the Hunter, is one of the most easily recognizable constellations in planet Earth's night sky. But Orion's stars and nebulas don't look quite as colorful to the eye as they do in this lovely camera image, taken early last month at the Black Forest Star Party from Cherry Springs State Park in Pennsylvania, USA. In this single exposure, cool red giant Betelgeuse takes on a yellowish tint as the brightest star at the far left. Otherwise Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse at the upper right, Bellatrix at the upper left, and Saiph at the lower right. Lined up in Orion's belt (bottom to top) are Alnitak, Alnilam, and Mintaka all about 1,500 light-years away, born of the constellation's well studied interstellar clouds. And if the middle "star" of Orion's sword looks reddish and fuzzy to you, it should. It's the stellar nursery known as the Great Nebula of Orion.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 16, 2008, 08:10:03 am
48 Years of Space Flight
Credit & Copyright: Ralf Vandebergh
Explanation: This year, NASA celebrated its 50th anniversary. Inspired to make his own contribution, astronomer Ralf Vandebergh set out to record images of some historic spacecraft in Earth orbit -- captured with his own modest equipment and a hand-guided, 10-inch, Newtonian reflecting telescope. One result is this intriguing composite effectively spanning 48 years of space flight! From a 1960 launch, on the left is the TIROS 2 satellite, one of the first successful weather satellites. While this TIROS (Television InfraRed Observation System) satellite stopped functioning in 1961, Vandeberg notes that if we could visit it now, we would still find video cameras and magnetic tape recorders. On the right, of course, is the ISS (International Space Station) including its recent addition, the Progress M-65 cargo vehicle, launched to the ISS just last month.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 04, 2008, 08:45:22 am
A Spectacular Rayed Crater on Mercury
Credit: MESSENGER, NASA, JHU APL, CIW
Explanation: Why does Mercury have so many rayed craters? No one is sure. The robotic MESSENGER spacecraft that is taking unprecedented images as it swoops past the innermost planet has provided dramatic confirmation that Mercury has more rayed craters than Earth's Moon. Pictured above, a particularly spectacular rayed crater spanning approximately 80 kilometers was imaged by MESSENGER during last month's flyby from about 20,000 kilometers up. The rays prevalence is a mystery because space weathering effects such as dust accumulation and solar wind attenuation should be greater on Mercury than on the Moon. Hypothesized solutions currently include the optical properties of Mercurian dust, and that Mercury's high mass and proximity to the Sun cause more violent impacts, thus typically raising more light material. MESSENGER will buzz past Mercury again next year before entering orbit in 2011
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 05, 2008, 08:49:27 am
The Double Ring Galaxies of Arp 147 from Hubble
Credit: M Livio et al. (STScI), ESA, NASA
Explanation: How could a galaxy become shaped like a ring? Even more strange: how could two? The rim of the blue galaxy pictured on the right shows an immense ring-like structure 30,000 light years in diameter composed of newly formed, extremely bright, massive stars. This blue galaxy is part of the interacting galaxy system known as Arp 147, and shows a ring because it has recently collided with the other galaxy in the frame, the red galaxy on the left. Unusually, even this red galaxy shows a ring like band, although it is seen nearly edge-on. When galaxies collide, they pass through each other -- their individual stars rarely come into contact. Clouds of interstellar gas and dust become condensed, causing a wave of star formation to move out from the impact point like a ripple across the surface of a pond. The above image was taken last week by NASA's Hubble Space Telescope to demonstrate the ability of its Wide Field Planetary Camera 2 after some recent technical difficulties.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 05, 2008, 07:17:29 pm
Seventeen Hundred Kilometers Above Enceladus
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA
Explanation: Above is one of the closest pictures yet obtained of Saturn's ice-spewing moon Enceladus. The image was taken from about 1,700 kilometers up as the robotic Cassini spacecraft zoomed by the fractured ice ball last week. Features the size of a bus are resolvable in this highly detailed image taken of Enceladus' active tiger stripe region. Very different from most other moons and planets, grooves and hills dot an alien moonscape devoid of craters. Space pioneers might wonder where, on such a highly textured surface, a future probe might land in search of freshly deposited ice, subsurface seas, or even indicators of life. Although appearing dark in the above contrast-enhanced image, the surface of Enceladus is covered with some of the brightest ice in the entire Solar System, reflecting about 99 percent of the light it receives. To help better understand this enigmatic world, Cassini is scheduled to swoop by Enceladus at least five more times.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 07, 2008, 08:44:00 am
A Sharper View of a Hazy Giant
Credit: ESO, F.Marchis, M.Wong (UC Berkeley); E.Marchetti, P.Amico, S.Tordo (ESO)
Explanation: This dramatic image of Jupiter is touted as the sharpest picture of the entire gas giant ever taken from the ground. The picture was made using a prototype instrument known as MAD (Multi-conjugate Adaptive optics Demonstrator) mounted on one of the European Southern Observatory's 8-meter diameter Very Large Telescope units in Chile. Working at infrared wavelengths the MAD instrument removes atmospheric blurring, the bane of earthbound telescopes, by using multiple guide stars and deformable mirrors to sense and correct for the distortions produced by turbulence in Earth's atmosphere. Hydrogen and methane deep in Jupiter's own thick atmosphere absorb light at infrared wavelengths. So, this sharper view shows the infrared sunlight reflected from the giant planet's high level haze prominent in the equatorial regions and near the poles. It reveals features as small as 300 kilometers across. The promising technique can also be applied to imaging other extended objects like star clusters and nebulae.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 07, 2008, 04:05:48 pm
Cygnus Trio
Credit & Copyright: J-P Metsävainio (Astro Anarchy)
Explanation: In this colorful mosaic, filaments of gas and dust span some 9 degrees across central Cygnus, a nebula rich constellation along the northern Milky Way. A trio of nebulae with popular names highlights the beautiful skyscape - the Butterfly, the Crescent, and the Tulip. At left, the Butterfly Nebula (IC 1318), lies near bright star Gamma Cygni. The Butterfly's expansive, glowing, wing-shaped gas clouds are divided by a dark dust lane. Near center, the Crescent Nebula (NGC 6888) is more compact, a cosmic bubble with a bright edge blown by winds from a massive Wolf-Rayet star. On the right is the Tulip Nebula (Sh2-101), a small emission region shaped like a blossoming flower viewed from the side. All are within a few thousand light-years of the Sun in the Orion spiral arm of our galaxy. The gorgeous mosaic is presented in false color, constructed from image data recorded through narrow band filters. The range of colors was created by a mapping of emission from hydrogen, sulfur and oxygen atoms in the nebula to red, green, and blue hues.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 08, 2008, 09:37:13 am
On the Trail of 2008 TC3
Credit: Mohamed Elhassan Abdelatif Mahir (Noub NGO), Dr. Muawia H. Shaddad (Univ. Khartoum),
Dr. Peter Jenniskens (SETI Institute/NASA Ames)
Explanation: On October 7, the early dawn over northern Sudan revealed this twisted, high altitude trail. Captured in a video frame, the long-lasting persistent train is from the impact of a small asteroid cataloged as 2008 TC3. That event was remarkable because it was the first time an asteroid was detected in space before crashing into planet Earth's atmosphere. In fact, after astronomers discovered 2008 TC3, the time and location of its impact were predicted based on follow-up observations. Later, the impact predictions were confirmed by sensors, including a Meteosat-8 image of a bright flash in the atmosphere. Astronomers are now hoping for more reports of local ground-based observations of what must have been a brilliant meteor streaking through Sudan's night sky. Additional reports could improve the chances of recovering meteorites.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 08, 2008, 11:14:47 pm
Comet Ikeya-Zhang Meets The ISS
Credit & Copyright Carol Lakomiak
Explanation: Still catching the Sun's rays, the International Space Station (ISS) cruises across the early evening sky above Tomahawk, Wisconsin, USA. Recorded on April 9 around 9 pm CDT in a 30 second exposure, the sunlit space station traced this bright streak moving east (right) through the constellation Cassiopeia. Below lies Comet Ikeya-Zhang sporting a visible tail. But while this photogenic comet is now fading from view, the ISS will be getting brighter. Hours after this picture was taken, the Space Shuttle Atlantis docked with the ISS, bringing another structure to add to the growing orbital outpost.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 09, 2008, 10:19:10 am
Two Black Holes Dancing in 3C 75
Credit: A. Ginsburg (U. Colorado - Boulder) et al., BGPS Team, GLIMPSE II Team
Explanation: What's happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources of gravitational waves.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 11, 2008, 08:42:17 am
The Cosmic Web of the Tarantula Nebula
Credit & Copyright: Joseph Brimacombe
Explanation: First cataloged as a star, 30 Doradus is actually an immense star forming region in nearby galaxy The Large Magellanic Cloud. The region's spidery appearance is responsible for its popular name, the Tarantula nebula, except that this tarantula is about 1,000 light-years across, and 180,000 light-years away in the southern constellation Dorado. If the Tarantula nebula were at the distance of the Orion Nebula (1,500 light-years), the nearest stellar nursery to Earth, it would appear to cover about 30 degrees (60 full moons) on the sky. The spindly arms of the Tarantula nebula surround NGC 2070, a star cluster that contains some of the brightest, most massive stars known. Intriguing details of the nebula are visible in this scientifically-colored image. The cosmic Tarantula also lies near the site of the closest recent supernova.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 12, 2008, 08:46:10 am
Phoenix and the Holy Cow
Image Credit: Marco Di Lorenzo, Kenneth Kremer,
Phoenix Mission, NASA, JPL, UA, Max Planck Inst., Spaceflight
Explanation: The northern Martian summer is waning. As predicted, a decline in daylight hours, deteriorating weather, and dust storms are preventing solar arrays on the Phoenix Mars Lander from providing power. Phoenix's last signal was received on November 2, its successful mission ending after more than five months in the arctic region of the Red Planet, a run that exceeded its planned operational lifetime. Attempting to discover if Mars' surface has ever been able to support microbial life, Phoenix performed an extensive analysis of the soil and returned a wealth of image data. Of course, one of the lander's most exciting results was the detection of water-ice near the Martian surface. Recorded in October, this picture from the lander's Robotic Arm Camera shows the region under the Phoenix with flat, exposed icy patches. That area caused researchers to exclaim "Holy Cow!" when it was first imaged a few days after the May 25 touchdown of the Phoenix Mars Lander.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 14, 2008, 08:38:25 am
A Bubble in Cygnus
Image Credit & Copyright: Keith Quattrocchi, Mel Helm
Explanation: Adrift in the rich star fields of the constellation Cygnus, this lovely, symmetric bubble nebula was only recently recognized and may not yet appear in astronomical catalogs. In fact, amateur astronomer Dave Jurasevich identified it as a nebula on July 6 in his images of the complex Cygnus region that included the Crescent Nebula (NGC 6888). He subsequently notified the International Astronomical Union. Only eleven days later the same object was independently identified by Mel Helm at Sierra Remote Observatories, imaged by Keith Quattrocchi and Helm, and also submitted to the IAU as a potentially unknown nebula. Their final composite image is seen here, including narrow-band image data that highlights the nebula's delicate outlines. What is the newly recognized bubble nebula? Like the Crescent Nebula itself, this cosmic bubble could be blown by winds from a massive Wolf-Rayet star, or it could be a spherically-shaped planetary nebula, a final phase in the life of a sun-like star.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 15, 2008, 04:57:58 pm
Fomalhaut b
Credit: NASA, ESA, P. Kalas, J. Graham, E. Chiang, E. Kite (Univ. California, Berkeley),
M. Clampin (NASA/Goddard), M. Fitzgerald (Lawrence Livermore NL),
K. Stapelfeldt, J. Krist (NASA/JPL)
Explanation: Fomalhaut (sounds like "foam-a-lot") is a bright, young, star, a short 25 light-years from planet Earth in the direction of the constellation Piscis Austrinus. In this sharp composite from the Hubble Space Telescope, Fomalhaut's surrounding ring of dusty debris is imaged in detail, with overwhelming glare from the star masked by an occulting disk in the camera's coronagraph. Astronomers now identify, the tiny point of light in the small box at the right as a planet about 3 times the mass of Jupiter orbiting 10.7 billion miles from the star (almost 14 times the Sun-Jupiter distance). Designated Fomalhaut b, the massive planet probably shapes and maintains the ring's relatively sharp inner edge, while the ring itself is likely a larger, younger analog of our own Kuiper Belt - the solar system's outer reservoir of icy bodies. The Hubble data represent the first visible-light image of a planet circling another star.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 15, 2008, 04:59:28 pm
Arp 273
Credit & Copyright: Adam Block, Mount Lemmon SkyCenter, University of Arizona
Explanation: The two prominent stars in the foreground of this colorful skyscape are well within our own Milky Way Galaxy. Their spiky appearance is due to diffraction in the astronomer's telescope. But the two eye-catching galaxies in view lie far beyond the Milky Way, at a distance of about 200 million light-years. Their distorted appearance is due to gravitational tides as the pair engage in close encounters. From our perspective, the bright cores of the galaxies are separated by about 80,000 light-years. Cataloged as Arp 273 (also as UGC 1810), the galaxies do look peculiar, but interacting galaxies are now understood to be common in the universe. In fact, the nearby large spiral Andromeda Galaxy is known to be some 2 million light-years away and approaching the Milky Way. Arp 273 may offer an analog of their far future encounter. Repeated galaxy encounters on a cosmic timescale can ultimately result in a merger into a single galaxy of stars.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Novembro 17, 2008, 08:38:24 am
Anticrepuscular Rays Over Colorado
Credit & Copyright: John Britton
Explanation: What's happening over the horizon? Although the scene may appear somehow supernatural, nothing more unusual is occurring than a setting Sun and some well placed clouds. Pictured above are anticrepuscular rays. To understand them, start by picturing common crepuscular rays that are seen any time that sunlight pours though scattered clouds. Now although sunlight indeed travels along straight lines, the projections of these lines onto the spherical sky are great circles. Therefore, the crepuscular rays from a setting (or rising) sun will appear to re-converge on the other side of the sky. At the anti-solar point 180 degrees around from the Sun, they are referred to as anticrepuscular rays. Pictured above is a particularly striking set of anticrepuscular rays photographed in 2001 from a moving car just outside of Boulder, Colorado, USA.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Janeiro 11, 2009, 11:00:28 am
In the Shadow of Saturn
Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA
Explanation: In the shadow of Saturn, unexpected wonders appear. The robotic Cassini spacecraft now orbiting Saturn recently drifted in giant planet's shadow for about 12 hours and looked back toward the eclipsed Sun. Cassini saw a view unlike any other. First, the night side of Saturn is seen to be partly lit by light reflected from its own majestic ring system. Next, the rings themselves appear dark when silhouetted against Saturn, but quite bright when viewed away from Saturn and slightly scattering sunlight, in the above exaggerated color image. Saturn's rings light up so much that new rings were discovered, although they are hard to see in the above image. Visible in spectacular detail, however, is Saturn's E ring, the ring created by the newly discovered ice-fountains of the moon Enceladus, and the outermost ring visible above. Far in the distance, visible on the image left just above the bright main rings, is the almost ignorable pale blue dot of Earth.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Fevereiro 04, 2009, 09:56:25 pm
A Dangerous Summer on HD 80606b
Illustration Credit: D. Kasen (et al.UCSC), NASA, JPL-Caltech
Explanation: On the distant planet HD 80606b, summers might be dangerous. Hypothetic life forms floating in HD 080606b's atmosphere or lurking on one of its (presently hypothetical) moons might fear the 1,500 Kelvin summer heat, which is hot enough not only to melt lead but also nickel. Although summers are defined for Earth by the daily amount of sunlight, summers on HD 80606b are more greatly influenced by how close the planet gets to its parent star. HD 80606b, about 200 light years distant, has the most elliptical orbit of any planet yet discovered. In comparison to the Solar System, the distance to its parent star would range from outside the orbit of Venus to well inside the orbit of Mercury. In this sequence, the night side of HD 80606b is computer simulated as it might glow in infrared light in nearly daily intervals as it passed the closest point in its 111-day orbit around its parent star. The simulation is based on infrared data taken in late 2007 by the Spitzer Space Telescope.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Fevereiro 05, 2009, 06:08:16 pm
NGC 604: X-rays from a Giant Stellar Nursery
Credit: X-ray: NASA / CXC / R. Tuellmann (Harvard-Smithsonian CfA) et al.;
Optical: NASA/AURA/STScI
Explanation: Some 3 million light-years distant in nearby spiral galaxy M33, giant stellar nursery NGC 604 is about 1,300 light-years across, or nearly 100 times the size of the Orion Nebula. In fact, among the star forming regions within the Local Group of galaxies, NGC 604 is second in size only to 30 Doradus, also known as the Tarantula Nebula in the Large Magellanic Cloud. This space-age color composite of X-ray data (in blue hues) from the Chandra Observatory, and Hubble optical data shows that NGC 604's cavernous bubbles and cavities are filled with a hot, tenuous, X-ray emitting gas. Intriguingly, NGC 604 itself is divided by a wall of relatively cool gas. On the western (right) side of the nebula, measurements indicate that material is likely heated to X-ray temperatures by the energetic winds from a cluster of about 200 young, massive stars. On the eastern side the X-ray filled cavities seem to be older, suggesting supernova explosions from the end of massive star evolution contribute to their formation.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Fevereiro 07, 2009, 02:28:34 pm
Space Station in the Moon
Credit & Copyright: Eric J. Zbinden
Explanation: On February 2nd, a first quarter Moon shone in planet Earth's early evening sky. As seen from a location on the US west coast near Mt. Hamilton, California, the International Space Station also arched above the horizon, crossing in front of the Moon's sunlit surface. The space station's transit lasted 0.49 seconds. This sharp exposure, a well-timed telescopic image, recorded the space station during the transit against the background of the Moon's smooth Mare Serenitatis (Sea of Serenity). The orbital outpost was traveling northwest to southeast (from 2 o'clock to 8 o'clock) at a range of 389 kilometers or about 230 miles. Of course, the Moon itself was 1,000 times farther away. In the remarkable photo, the glinting station also offers a hint of the bluish reflection of earthlight
Título: Re: APOD DO DIA
Enviado por: ahlberto em Fevereiro 07, 2009, 02:30:44 pm
Comet Lulin Tails
Credit & Copyright: Joseph Brimacombe
Explanation: Sweeping through the inner solar system, Comet Lulin is easily visible in both northern and southern hemispheres with binoculars or a small telescope. Recent changes in Lulin's lovely greenish coma and tails are featured in this two panel comparison of images taken on January 31st (top) and February 4th. Taken from dark New Mexico Skies, the images span over 2 degrees. In both views the comet sports an apparent antitail at the left -- the comet's dust tail appearing almost edge on from an earth-based perspective as it trails behind in Lulin's orbit. Extending to the right of the coma, away from the Sun, is the beautiful ion tail. Remarkably, as captured in the bottom panel, Comet Lulin's ion tail became disconnected on February 4, likely buffeted and torn away by magnetic fields in the solar wind. In 2007 NASA satellites recorded a similar disconnection event for Comet Encke. Don't worry, though. Comet tails can grow back.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Fevereiro 09, 2009, 04:15:46 pm
Anemic Galaxy NGC 4921 at the Edge
Credit: NASA, ESA, K. Cook (LLNL)
Explanation: How far away is spiral galaxy NGC 4921? Although presently estimated to be about 320 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe. Toward this goal, this image was taken by the Hubble Space Telescope in order to help identify key stellar distance markers know as Cepheid variable stars. Since NGC 4921 is a member of the Coma Cluster of Galaxies, refining its distance would also allow a better distance determination to one of the largest nearby clusters in the local universe. The magnificent spiral NGC 4921 has been informally dubbed anemic because of its low rate of star formation and low surface brightness. The remarkably sharp image was made with Hubble's Advanced Camera for Surveys, currently in need of repair. Visible in the image are, from the center, a bright nucleus, a bright central bar, a prominent ring of dark dust, blue clusters of recently formed stars, several smaller companion galaxies, unrelated galaxies in the far distant universe, and unrelated stars in our Milky Way Galaxy.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Fevereiro 10, 2009, 10:05:42 pm
Orion's Belt
Credit & Copyright: Martin Mutti, Astronomical Image Data Archive
Explanation: Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (left to right) along the diagonal in this gorgeous cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie about 1,500 light-years away, born of Orion's well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have intriguing and some surprisingly familiar shapes, including the dark Horsehead Nebula and Flame Nebula near Alnitak at the lower left. The famous Orion Nebula itself lies off the bottom of this star field that covers about 4.5x3.5 degrees on the sky. This image was taken last month with a digital camera attached to a small telescope in Switzerland, and better matches human color perception than a more detailed composite taken over 15 years ago.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 07, 2009, 02:14:36 pm
Comet Lulin and Distant Galaxies
Credit & Copyright: Johannes Schedler (Panther Observatory)
Explanation: Now fading in our night sky, Comet Lulin has provided some lovely cosmic vistas. Moving rapidly against the background of stars, Lulin briefly posed with the likes of Saturn, and Regulus (Alpha Leo). But here it is seen against a field of distant galaxies. To reveal the faint background galaxies and trace the comet's fading tail, the remarkable picture is a blended composite of telescopic exposures aligned with the both the stars and the speedy comet. The largest galaxies seen left of the comet's head or coma are cataloged as NGC 3016, NGC 3019, NGC 3020 and NGC 3024 and lie at a distance of 100 million light-years or so. When the exposures were made, on February 28, the comet was about 3.6 light-minutes from Earth.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 09, 2009, 08:52:27 am
Kepler's Streak
Credit & Copyright: Ben Cooper
Explanation: Streaking skyward, a Delta II rocket carries NASA's Kepler spacecraft aloft into the clear night of March 6. The dramatic scene was recorded in a time exposure from the crowded pier in Jetty Park at the northern end of Cocoa Beach, Florida, about 3 miles from the Cape Canaveral launch site. Kepler's mission is to search for Earth-like planets orbiting in the habitable zone of other stars. A planet orbiting within a star's habitable zone would have a surface temperature capable of supporting liquid water, an essential ingredient for life as we know it. To find Earth-like planets, Kepler's telescope and large, sensitive camera will examine a rich star field near the plane of our Milky Way Galaxy. Located in the constellation Cygnus, Kepler's field of view will allow it to monitor the brightness of many stars in the solar neighborhood and detect a slight dimming as a potential Earth-like planet crosses in front of the star
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 10, 2009, 05:48:06 pm
Horsehead and Orion Nebulae
Credit & Copyright: Dale J. Martin (Massapoag Pond Obs.)
Explanation: Adrift 1,500 light-years away in one of the night sky's most recognizable constellations, the glowing Orion Nebula and the dark Horsehead Nebula are contrasting cosmic vistas. They appear in opposite corners of this stunning mosaic taken with a digital camera attached to a small telescope. The magnificent emission region, the Orion Nebula (aka M42), lies at the upper right of the picture. Immediately to its left is a prominent bluish reflection nebula sometimes called the Running Man. The Horsehead nebula appears as a dark cloud, a small silhouette notched against the long red glow at the lower left. Alnitak is the easternmost star in Orion's belt and is seen as the brightest star to the left of the Horsehead. Below Alnitak is the Flame Nebula, with clouds of bright emission and dramatic dark dust lanes. Pervasive tendrils of glowing hydrogen gas are easily traced throughout the region in this deep field image of the same region
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 11, 2009, 09:21:23 pm
Lunar X
Credit & Copyright: Jerry Lodriguss (Catching the Light)
Explanation: The striking X near the center of this lunarscape is easily visible in binoculars or a small telescope. Yet, not too many have seen it. The catch is, this lunar X is only apparent during a four hour period just before the Moon's first quarter phase. At the terminator, or shadow line between lunar day and night, the X illusion is produced by a configuration of the craters Blanchinus, La Caille and Purbach. Near the Moon's first quarter phase, an astronaut standing close to the craters' position would see the slowly rising Sun very near the horizon. Temporarily, the crater walls would be in sunlight while the crater floors were still in darkness. Seen from planet Earth, contrasting sections of bright walls against the dark floors by chance look remarkably like an X. This sharp image of the Lunar X was captured at approximately 11:59 UT on March 3, 2009. The Moon's first quarter phase was at 7:46 UT on March 4.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 12, 2009, 08:56:57 pm
Thor's Helmet (NGC 2359) and Planetary Nebula
Credit & Copyright: Rogelio Bernal Andreo, Ray Gralak
Explanation: At the right, Thor's Helmet (NGC 2359) seems to gaze across a lovely star field. The broad skyscape itself covers about 1.5 degrees or 3 full moons toward the constellation Canis Major. A close look at the lower left corner of the image might identify the object of the cosmic stare as a faint, round nebula. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. The helmet is actually more like an interstellar bubble, blown as a fast wind from the bright, massive star near the bubble's center sweeps through a surrounding molecular cloud. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre- supernova stage of evolution. In contrast, the faint, round nebula is a planetary nebula, the gaseous shroud of a dying lower mass star. The distance to Thor's Helmet is estimated to be about 15,000 light-years.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 13, 2009, 06:16:35 pm
Hickson Compact Group 90
Credit: NASA, ESA, R. Sharples (Univ. Durham)
Explanation: Scanning the skies for galaxies, Canadian astronomer Paul Hickson and colleagues identified some 100 compact groups of galaxies, now appropriately called Hickson Compact Groups (HCGs). This sharp Hubble image shows one such galaxy group, HCG 90, in startling detail. Three galaxies are revealed to be strongly interacting: a dusty spiral galaxy stretched and distorted between a pair of large elliptical galaxies. The close encounter will trigger furious star formation. On a cosmic timescale, the gravitational tug of war will eventually result in the merger of the trio into a large single galaxy. The merger process is now understood to be a normal part of the evolution of galaxies, including our own Milky Way. HCG 90 lies about 100 million light-years away in the constellation Piscis Austrinus. This Hubble view spans about 80,000 light-years at that estimated distance. Of course, Hickson Compact Groups also make for rewarding viewing for Earth-bound astronomers with more modest sized telescopes.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 14, 2009, 09:01:46 pm
Haute-Provence Star Trails
Credit & Copyright: Alexandre Santerne
Explanation: Fix your camera to a tripod and you can record the graceful trails traced by the stars as planet Earth rotates on its axis. For example, this dramatic 5 hour long exposure was made on February 24 from Haute-Provence Observatory (OHP) in southeastern France. Actually a composite of 300 consecutive 1-minute exposures, the image nicely shows stars near the celestial equator tracing nearly straight lines in projection, while stars north and south of the equator, respectively, appear to circle the north and south celestial poles. Domes at the bottom left and right house the OHP telescopes. Brilliant planet Venus makes the short bright trail at the lower right, while trails of stars in the end near the lower right observatory dome. Sirius, alpha star of Canis Major, traces the bright arc over the dome at the left. Astronomer Alexandre Santerne also briefly illuminated a foreground oak tree during the exposure sequence.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 15, 2009, 05:38:22 pm
A Prominent Solar Prominence from SOHO
Credit: SOHO - EIT Consortium, ESA, NASA
Explanation: What's happened to our Sun? It was sporting a spectacular -- but not very unusual -- solar prominence. A solar prominence is a cloud of solar gas held above the Sun's surface by the Sun's magnetic field. In 2004, NASA's Sun-orbiting SOHO spacecraft imaged an impressively large prominence hovering over the surface, pictured above. The Earth would easily fit under the hovering curtain of hot gas. A quiescent prominence typically lasts about a month, and may erupt in a Coronal Mass Ejection (CME) expelling hot gas into the Solar System. Although somehow related to the Sun's changing magnetic field, the energy mechanism that creates and sustains a Solar prominence is still a topic of research.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 16, 2009, 08:47:13 am
Martian Moon Deimos from MRO
Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: Mars has two tiny moons, Phobos and Deimos. Pictured above, in a recently release image by HiRISE camera onboard the Mars-orbiting Mars Reconnaissance Orbiter (MRO), is Deimos, the smaller moon of Mars. Deimos is one of the smallest known moons in the Solar System measuring only about 15 kilometers across. The diminutive Martian moon was discovered in 1877 by Asaph Hall, an American astronomer working at the US Naval Observatory in Washington D.C. The existence of two Martian moons was predicted around 1610 by Johannes Kepler, the astronomer who derived the laws of planetary motion. In this case, Kepler's prediction was not based on scientific principles, but his writings and ideas were so influential that the two Martian moons are discussed in works of fiction such as Jonathan Swift's Gulliver's Travels, written in 1726, over 150 years before their actual discovery
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 17, 2009, 08:37:53 am
Tycho's Supernova Remnant
Credit: X-ray: NASA/CXC/SAO; Infrared: NASA/JPL-Caltech; Optical: MPIA, Calar Alto, O. Krause et al.
Explanation: What star created this huge puffball? Pictured above is the best multi-wavelength image yet of Tycho's supernova remnant, the result of a stellar explosion first recorded over 400 years ago by the famous astronomer Tycho Brahe. The above image is a composite of an X-ray image taken by the orbiting Chandra X-ray Observatory, an infrared image taken by the orbiting Spitzer Space Telescope, and an optical image taken by the 3.5-meter Calar Alto telescope located in southern Spain. The expanding gas cloud is extremely hot, while slightly different expansion speeds have given the cloud a puffy appearance. Although no one is sure which star created SN 1572, a star dubbed Tycho G, too dim to be easily discerned here, is being studied as the possible progenitor. Finding the progenitor remnant of Tycho's supernova is particularly important because the supernova was recently determined to be of Type Ia. The peak brightness of Type Ia supernovas is thought to be well understood, making them quite valuable in calibrating how our universe dims distant objects.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 18, 2009, 07:41:55 pm
GLOBE at Night: Help Track Light Pollution
Credit & Copyright: Globe at Night Project, UCAR, International Year of Astronomy 2009
Explanation: How many stars can you see? Through next week, the GLOBE at Night project invites people from all over the world to go outside at night, look up, and see! Specifically, people are invited to go out an hour after sunset and look for the constellation Orion toward the west. Rather than count Orion's stars directly, however, the GLOBE at Night website has made things easier by providing several star charts to which you can compare your view of Orion. Possible matches extend from a bright sky where only a few Orion stars are visible, to a very dark sky where over 100 Orion stars are visible. Pictured above are results from last year's sky observation campaign. Since 2009 is the International Year of Astronomy, it is hoped that an even better map can be created this year. By participating in this easy and fun activity, you are helping humanity to better understand how light pollution is changing across the Earth.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 21, 2009, 03:09:26 am
Sunset at the Portara
Credit & Copyright: Anthony Ayiomamitis (TWAN)
Explanation: Today, the Sun crosses the celestial equator heading north at 11:44 UT. Known as an equinox, this astronomical event marks the first day of spring in the northern hemisphere and autumn in the south. It also marks the beginning of Norouz, the Persian (Iranian) new year. Equinox means equal night. With the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. Of course, in the north the days will grow longer, the Sun marching higher in the sky as summer approaches. To celebrate the equinox, consider this scenic view of the setting Sun from the island of Naxos in the Aegean Sea. Recorded last June, the well-planned image captures the Portara (big door) in a dramatic silhouette. Measuring about 6 by 3.5 meters, the Portara is the large entrance to the Greek island's ancient, unfinished Temple of Apollo.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 23, 2009, 06:41:51 pm
The Seahorse of the Large Magellanic Cloud
Credit: NASA, ESA, and M. Livio (STScI)
Explanation: To some it may look to some like a big space monster, but it is more big than monster. To others it may look like a grazing seahorse, but the dark object toward the image right is actually an inanimate pillar of smoky dust about 20 light years long. The curiously-shaped dust structure occurs in our neighboring Large Magellanic Cloud, in a star forming region very near the expansive Tarantula Nebula. The energetic nebula is creating a star cluster named NGC 2074, whose center is visible just off the top of the image in the direction of the neck of the seahorse. The above representative color image was taken last year by the Hubble Space Telescope's Wide Field Planetary Camera 2 in honor of Hubble's 100,000th trip around the Earth. As young stars in the cluster form, their light and winds will slowly erode the dust pillars away over the next million years.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 24, 2009, 08:24:33 pm
Martian Dunes and the Shadow of Opportunity
Credit: Mars Exploration Rover Mission, JPL, NASA
Explanation: Human made robots continue to roll across the surface of Mars. Both Opportunity and its sister rover Spirit are in their sixth year on Mars, exploring the red planet for years longer than original expectations. Pictured above is a composite of recent images taken by the navigation camera on top of the Opportunity rover in Meridiani Planum. Visible are parallel rover tracks, rippling sand dunes, light-colored bedrock protrusions, metallic rover parts, and the dark shadow of the sometimes-artistic robotic photographer. Currently, Opportunity is on its way toward huge Endeavor crater, while Spirit is trying to climb an unusual rock structure known as Home Plate. If it can survive the harsh martian environment, Opportunity should arrive at Endeavor crater in about two years, at which time it may revolutionize human knowledge of this ancient martian landform.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 28, 2009, 09:39:51 am
The Seagull Nebula
Credit & Copyright: Frank Barrett, Steve Davis
Explanation: Images from two different cameras, a digital SLR and an astronomical CCD camera, are combined in this color starscape. Both cameras made use of the same telescope at the oceanside Winter Star Party in the Florida Keys, appropriately creating this portrait of the Seagull Nebula. The wide view covers a 4x3 degree swath across the plane of the Milky Way, near the direction of Sirius, alpha star of the constellation Canis Major. Of course, the broad region includes objects with other catalog designations: notably NGC 2327 - a compact, dusty emission region with an embedded massive star that forms the bird's head (above center), and IC 2177 - forming the sweeping arc of the seagull's wings. Dominated by the reddish glow of atomic hydrogen, the complex of cosmic gas and dust clouds with bright young stars spans over 250 light-years at an estimated 3,800 light-year distance.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 29, 2009, 07:14:11 pm
Signals of a Strange Universe
Credit: High-Z Supernova Search Team, HST, NASA
Explanation: Eleven years ago results were first presented indicating that most of the energy in our universe is not in stars or galaxies but is tied to space itself. In the language of cosmologists, a large cosmological constant is directly implied by new distant supernovae observations. Suggestions of a cosmological constant (lambda) were not new -- they have existed since the advent of modern relativistic cosmology. Such claims were not usually popular with astronomers, though, because lambda is so unlike known universe components, because lambda's value appeared limited by other observations, and because less- strange cosmologies without lambda had previously done well in explaining the data. What is noteworthy here is the seemingly direct and reliable method of the observations and the good reputations of the scientists conducting the investigations. Over the past eleven years, independent teams of astronomers have continued to accumulate data that appears to confirm the existence of dark energy and the unsettling result of a presently accelerating universe. The above picture of a supernova that occurred in 1994 on the outskirts of a spiral galaxy was taken by one of these collaborations.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Março 30, 2009, 09:27:14 pm
Possible Mud Volcanoes on Mars
Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: Is this a mud volcano on Mars? If so, could it be dredging up martian microbes? This strange possibility has been suggested recently and seems to fit several recent observations of Mars. First of all, hills like this seem to better resemble mud volcanoes on Earth than lava volcanoes and impact craters on Mars. Next, the pictured dome has an unusually textured surface consistent with fractured ice. Infrared images from space indicate that hills like this cool more quickly than surrounding rock, consistent with a dried mud composition. The hills also reflect colors consistent with a composition that formed in the presence of water. Finally, unusual plumes of gas containing methane have been found on Mars with unknown origin. These gas plumes could conceivably have been liberated by mud volcanoes, were the initially warm mud to contain methane-producing microbes drifting in a previously unobservable underground lake. A candidate mud volcano over 100 meters across is pictured above in the northern plains of Mars.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 02, 2009, 06:13:40 pm
100 Hours of Astronomy Begins
Credit & Copyright: Tamas Ladanyi (TWAN)
Explanation: Today, 100 Hours of Astronomy begins, a cornerstone project of the International Year of Astronomy 2009 celebrating the 400th anniversary of Galileo's original telescopic exploration of the sky. Running from April 2 through April 5, many different public programs are planned worldwide as part of the project, starting with today's opening event at the Franklin Institute in Philadelphia. Featuring one of Galileo's two remaining telescopes, the event will be webcast live. Of course, the sky examined by Galileo can still be appreciated today, with much more capable instruments that are widely available. But this skyward view from a private observatory in Veszprem Hungary also includes objects Galileo did not see when he gazed into the night. Recorded on March 26, the image captures the paired trails of the International Space Station (the brighter trail) and the shuttle orbiter Discovery in low Earth orbit, as well as the streak of a passing airplane.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 06, 2009, 05:22:45 pm
International Space Station Expands Again
Credit: STS-119 Shuttle Crew, NASA
Explanation: The developing International Space Station (ISS) has changed its appearance again. In a recently completed mission, the Space Shuttle orbiter Discovery visited the ISS and added components that included a new truss and new solar panels. The entire array of expansive solar panels is visible in the above picture taken by the Discovery Crew after leaving the ISS to return to Earth. The world's foremost space outpost can be seen developing over the past several years by comparing the above image to past images. Also visible above are many different types of modules, a robotic arm, and a supply ship. Construction began on the ISS in 1998.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 07, 2009, 07:05:29 pm
The Colliding Spiral Galaxies of Arp 274
Credit: NASA, ESA, M. Livio (STScI) and the Hubble Heritage Team (STScI/AURA)
Explanation: Two galaxies are squaring off in Virgo and here are the latest pictures. When two galaxies collide, the stars that compose them usually do not. This is because galaxies are mostly empty space and, however bright, stars only take up only a small fraction of that space. But during the collision, one galaxy can rip the other apart gravitationally, and dust and gas common to both galaxies does collide. If the two galaxies merge, black holes that likely resided in each galaxy center may eventually merge. Because the distances are so large, the whole thing takes place in slow motion -- over hundreds of millions of years. Besides the two large spiral galaxies, a smaller third galaxy is visible on the far left of the above image of Arp 274, also known as NGC 5679. Arp 274 spans about 200,000 light years across and lies about 400 million light years away toward the constellation of Virgo.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 09, 2009, 05:31:44 pm
Venus Near Inferior Conjunction
Credit & Copyright: Eddie Guscott
Explanation: This remarkable picture of a slender crescent Venus was made during daylight hours on March 26. Venus was then very near inferior conjunction, its closest approach to a point on a line directly between Earth and the Sun. So, daylight was a good time to carefully record the telescopic view when both Venus and Sun were high in the daytime sky. Near inferior conjunction, Venus is closest to us and at its largest apparent size, but Venus is also strongly backlit by sunlight, presenting its night side partially outlined by a narrow crescent. What makes the image remarkable are the faint arcs extending beyond the sunlit crescent around to the night side of Venus, due to sunlight filtering through the planet's dense atmosphere. Astronomer Eddie Guscott reports from his site in Essex, England that the faint extensions came and went as the Earth's atmospheric blurring changed. His image was constructed from 85 of the sharpest frames chosen from thousands taken with a webcam and telescope.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 10, 2009, 12:23:30 am
Unusual Dusty Galaxy NGC 7049
Credit: NASA, ESA and W. Harris (McMaster University)
Explanation: How was this unusual looking galaxy created? No one is sure, especially since spiral galaxy NGC 7049 looks so strange. NGC 7049's striking appearance is primarily due to an unusually prominent dust ring seen mostly in silhouette. The opaque ring is much darker than the din of millions of bright stars glowing behind it. Besides the dark dust, NGC 7049 appears similar to a smooth elliptical galaxy, although featuring surprisingly few globular star clusters. NGC 7049 is pictured above as imaged recently by the Hubble Space Telescope. The bright star near the top of NGC 7049 is an unrelated foreground star in our own Galaxy. Not visible here is an unusual central polar ring of gas circling out of the plane near the galaxy's center. Since NGC 7049 is the brightest galaxy in its cluster of galaxies, its formation might be fostered by several prominent and recent galaxy collisions. NGC 7049 spans about 150 thousand light years and lies about 100 million light years away toward the constellation of Indus.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 11, 2009, 01:40:42 pm
ISS and Astronaut
Credit & Copyright: Ralf Vandebergh
Explanation: These two frames, taken with a video camera and a telescope, reveal remarkable details of the International Space Station (ISS) orbiting some 350 kilometers above planet Earth. Recorded during last month's visit by the crew of shuttle orbiter Discovery on mission STS-119, the pictures show extended solar arrays glinting in bright sunlight against a dark sky. They also likely capture the blurred image of a spacewalking astronaut during the mission's EVA-2 (Extravehicular Activity-2)! The astronaut is installing equipment along one of the station's truss assemblies. Astronomer Ralf Vandebergh, who often images the ISS during its favorable passes through Dutch skies, comments that no other bright ISS structures occupy the position indicated in the inset, and that a reflective, white-suited astronaut would be visible against the truss and correspond to the bright blur. Vandebergh notes that the timing and location further suggest the spacewalker is STS-119 astronaut Joseph Acaba.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 11, 2009, 10:34:32 pm
The Big Picture
Credit & Copyright: Dennis di Cicco (TWAN) & Sean Walker, Skyandtelescope.com
Explanation: Intricate, glowing nebulae that shine in planet Earth's night sky are beautiful to look at in deep images made with telescopes and sensitive cameras. But they are faint and otherwise invisible to the naked-eye. That makes their relative location and extent on the sky difficult to appreciate. So, consider this impressive composite image of a wide region of the northern winter sky. With a total exposure time of 40 hours, the painstaking mosaic presents a nebula-rich expanse known as the Orion-Eridanus Superbubble above a house in suburban Boston, USA. Within the wide and deep view are nebulae more often seen in narrower views, including the Great Orion Nebula, the Rosette Nebula, the Seagull Nebula, the California Nebula, and Barnard's Loop. The familiar constellation of Orion itself is just above the foreground house. Brightest star Sirius is left of the roof, and the recognizable Pleiades star cluster is above the tree at the right. A version of the big picture that includes simple constellation guidelines is available here.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 14, 2009, 08:25:05 pm
M101: The Pinwheel Galaxy
Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona
Explanation: Why do many galaxies appear as spirals? A striking example is M101, shown above, whose relatively close distance of about 27 million light years allows it to be studied in some detail. Recent evidence indicates that a close gravitational interaction with a neighboring galaxy created waves of high mass and condensed gas which continue to orbit the galaxy center. These waves compress existing gas and cause star formation. One result is that M101, also called the Pinwheel Galaxy, has several extremely bright star-forming regions (called HII regions) spread across its spiral arms. M101 is so large that its immense gravity distorts smaller nearby galaxies.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 17, 2009, 08:57:40 pm
Jagged Shadows May Indicate Saturn Ring Particles
Credit: NASA, JPL, Space Science Institute
Explanation: What's causing unusual jagged shadows on Saturn's rings? No one is yet sure. As Saturn nears equinox, its rings increasingly show only their thin edge to the Earth and Sun. As a result, Saturn's moons now commonly cast long shadows onto the rings. An example of this is the elongated vertical shadow of Mimas seen on the above right. The series of shorter, jagged shadows that run diagonally, however, are more unusual. Now Saturn's rings have been known to be made of particles for hundreds of years, but these particles have so far escaped direct imaging. It is therefore particularly exciting that a preliminary hypothesis holds that these jagged shadows are silhouettes of transient groups of ring particles temporarily held close by their own gravity. Future work will surely continue, as the robotic Cassini spacecraft orbiting Saturn that took the above image will continue to photograph Saturn's magnificent rings right through Saturn's equinox this August.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 17, 2009, 09:00:35 pm
Castle and Full Moon
Credit & Copyright: Paolo Tanga, Observatoire de la Cote d'Azur
Explanation: Clouds couldn't hide this bright Full Moon as it rose last week over the medieval castle of Tourrette-Levens near Nice, France. Exactly full on April 9 at 1456 UT, it followed the March equinox, making it the first Full Moon of spring in the north and autumn in the southern hemisphere. Known as the Easter Moon, it fixes the date for the Christian celebration of Easter on the first Sunday after the first Full Moon of northern spring. Also called the Grass Moon or Egg Moon in the north, in the southern hemisphere, following the autumnal equinox, this Full Moon shines throughout the night as a Hunter's Moon.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 17, 2009, 09:02:55 pm
Medieval Astronomy from Melk Abbey
Credit: Paul Beck (Univ. Vienna), Georg Zotti (Vienna Inst. Arch. Science)
Copyright: Library of Melk Abbey, Frag. 229
Explanation: Discovered by accident, this manuscript page provides graphical insight to astronomy in medieval times, before the Renaissance and the influence of Nicolaus Copernicus, Tycho de Brahe, Johannes Kepler, and Galileo. The intriguing page is from lecture notes on astronomy compiled by the monk Magister Wolfgang de Styria before the year 1490 at Melk Abbey in Austria. The top panels clearly illustrate the necessary geometry for a lunar (left) and solar eclipse in the Earth-centered Ptolemaic system. At lower left is a diagram of the Ptolemaic view of the solar system and at the lower right is a chart to calculate the date of Easter Sunday in the Julian calendar. Text at the upper right explains the movement of the planets according to the Ptolemaic system. The actual manuscript page is on view at historic Melk Abbey as part of a special exhibition during the International Year of Astronomy.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 19, 2009, 09:22:44 pm
NGC 1333 Stardust
Credit & Copyright: Stephen Leshin
Explanation: NGC 1333 is seen in visible light as a reflection nebula, dominated by bluish hues characteristic of starlight reflected by dust. A mere 1,000 light-years distant toward the heroic constellation Perseus, it lies at the edge of a large, star-forming molecular cloud. This striking close-up view spans about 4 light-years at the estimated distance of NGC 1313. It shows details of the dusty region along with hints of contrasting emission in red jets and glowing gas from recently formed stars. In fact, NGC 1333 contains hundreds of stars less than a million years old, most still hidden from optical telescopes by the pervasive stardust. The chaotic environment may be similar to one in which our own Sun formed over 4.5 billion years ago
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 19, 2009, 09:24:11 pm
The View Near a Black Hole
Drawing Credit: April Hobart, CXC
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.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 20, 2009, 04:16:17 pm
Flowing Barchan Sand Dunes on Mars
Credit: HiRISE, MRO, LPL (U. Arizona), NASA
Explanation: When does Mars act like a liquid? Although liquids freeze and evaporate quickly into the thin atmosphere of Mars, persistent winds may make large sand dunes appear to flow and even drip like a liquid. Visible on the above image right are two flat top mesas in southern Mars, where the season is changing from Spring to Summer. A light dome topped hill is also visible on the far left of the image. As winds blow from right to left, flowing sand on and around the hills leaves picturesque streaks. The dark arc-shaped droplets of fine sand are called barchans, and are the interplanetary cousins of similar Earth-based sand forms. Barchans can move intact downwind and can even appear to pass through each other. Over the past few weeks, winds on southern Mars have been kicking up dust and are being watched to see if they escalate into another of Mars' famous planet-scale sand storms.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 29, 2009, 12:01:11 am
NGC 4565: Galaxy on the Edge
Credit & Copyright: Roth Ritter (Dark Atmospheres)
Explanation: Is our Galaxy this thin? We believe so. Magnificent spiral galaxy NGC 4565 is likely similar to our own spiral galaxy, but viewed edge-on from far away. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky as it lies in the faint but well-groomed constellation Coma Berenices. This sharp color image reveals the galaxy's bulging central core dominated by light from a population of older, yellowish stars. The core is dramatically cut by obscuring dust lanes which lace NGC 4565's thin galactic plane. NGC 4565 lies about 30 million light-years distant and spans over 100,000 light-years in diameter. Visible through a small telescope, some sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 30, 2009, 02:38:18 pm
GRB 090423: The Farthest Explosion Yet Measured
Credit: Gemini Observatory / NSF / AURA, D. Fox & A. Cucchiara (Penn State U.), and E. Berger (Harvard Univ.)
Explanation: An explosion so powerful it was seen clear across the visible universe was recorded in gamma-radiation last week by NASA's orbiting Swift Observatory. Farther than any known galaxy, quasar, or optical supernova, the gamma-ray burst recorded last week was clocked at redshift 8.2, making it the farthest explosion of any type yet detected. Occurring only 630 million years after the Big Bang, GRB 090423 detonated so early that astronomers had no direct evidence that anything explodable even existed back then. The faint infrared afterglow of GRB 090423 was recovered by large ground telescopes within minutes of being discovered. The afterglow is circled in the above picture taken by the large Gemini North Telescope in Hawaii, USA. An exciting possibility is that this gamma-ray burst occurred in one of the very first generation of stars and announced the birth of an early black hole. Surely, GRB 090423 provides unique data from a relatively unexplored epoch in our universe and a distant beacon from which the intervening universe can be studied.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Abril 30, 2009, 02:40:16 pm
Framed by Clouds
Credit & Copyright: Pete Lawrence (Digital-Astronomy)
Explanation: Last Sunday's fading evening twilight featured a young crescent Moon along the western horizon. The young Moon also shared the sky with the lovely Pleiades star cluster and wandering planet Mercury. Framed by clouds in this serene skyscape from Selsey, UK, a similar twilight scene was visible around the globe. Emerging from the cloud bank below the Pleiades, the narrow sunlit lunar crescent is overexposed. Still, the Moon's dim night side is impressively clear, illuminated by earthshine. Bright, innermost planet Mercury lies near the bottom of the field. Mercury will remain near the Pleiades, low in the west after sunset over the coming days, an ongoing conjunction of planet and star cluster that will offer skygazers some excellent binocular views.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Maio 05, 2009, 08:46:08 am
Titan Beyond the Rings
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA
Explanation: When orbiting Saturn, be sure to watch for breathtaking superpositions of moons and rings. One such picturesque vista was visible recently to the robot Cassini spacecraft now orbiting Saturn. In 2006 April, Cassini captured Saturn's A and F rings stretching in front of cloud-shrouded Titan. Near the rings and appearing just above Titan was Epimetheus, a moon which orbits just outside the F ring. The dark space in the A ring is called the Encke Gap, although several thin knotted ringlets and even the small moon Pan orbit there. Cassini and curious Earthlings await the coming Saturnian equinox this summer when the ring plane will point directly at the Sun. Mysterious spokes and telling shadows are expected to become visible that might give away more clues about the nature of Saturn's ring particles.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Maio 18, 2009, 09:04:27 am
Moon Rays Over Thurso Castle
Credit & Copyright: Stewart Watt
Explanation: What's happening over that castle? While waiting for the Moon to rise last month in Thurso, Scotland, amateur astrophotographer Stewart Watt took a three minute exposure of the background stars. The above image was the surprising result. Patchy clouds in front of the rising moon created crepuscular rays streaming across the night sky in spectacular fashion. In the foreground is a stone tower from Thurso Castle, a 12th century fortress augmented in the 17th century. Above the crepuscular moon rays are stars, many from the constellation of the Lion (Leo). Visible to the right of the tower is the planet Saturn.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Junho 24, 2009, 08:50:10 am
Noctilucent Clouds Over Germany
Credit & Copyright: Christoph Rollwagen
Explanation: Sometimes it's night on the ground but day in the air. As the Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore, at sunset on the ground, sunlight still shines on clouds above. Under usual circumstances, a pretty sunset might be visible, but unusual noctilucent clouds float so high up they can be seen well after dark. Pictured above last week, a network of noctilucent clouds cast an eerie white glow after dusk, beyond a local field near Potsdam, Germany. Although noctilucent clouds are thought to be composed of small ice-coated particles, much remains unknown about them. Satellites launched to help study these clouds includes Sweden's Odin and NASA's AIM. Recent evidence indicates that at least some noctilucent clouds result from freezing water exhaust from Space Shuttles.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Junho 25, 2009, 07:56:01 am
Sarychev Peak Volcano in Stereo
Credit: Expedition 20 Crew - International Space Station, NASA
Stereo Image: Patrick Vantuyne
Explanation: From 400 kilometers above planet Earth, the Expedition 20 Crew onboard the International Space Station (ISS) was able to witness a remarkable event from a remarkable vantage point -- the June 12 eruption of the Sarychev Peak Volcano. The active volcano is located in Russia's Kuril Island chain, stretching to the northeast of Japan. Emphasizing the orbital perspective, this stunning color stereo view was made by combining two images from the ISS and is intended to be viewed with red/blue glasses (red for the left eye). Punching upwards into the atmosphere at an early stage of the eruption, the volcanic plume features a brown column of ash topped with a smooth, bubble-like, white cloud that is likely water condensation. Below, a cloud of denser grey ash slides down the volcanic slope. About 1.5 kilometers of the island coastline is visible at ground level. The evolving ash plume posed no danger to the Expedition 20 crew, but commercial airline flights were diverted away from the region to minimize the danger of engine failures from ash intake
Título: Re: APOD DO DIA
Enviado por: ahlberto em Junho 26, 2009, 04:15:36 pm
Solstice to Solstice Solargraph
Credit & Copyright: Maciej Zapiór
Explanation: This six month long exposure compresses the time from solstice to solstice (~ December 21, 2008 to June 20, 2009) into a single point of view. Dubbed a solargraph, the unconventional picture was recorded with a pinhole camera made from an aluminum can lined with a piece of photographic paper. Fixed to a single spot for the entire exposure, the simple camera continuously records the Sun's daily path as a glowing trail burned into the photosensitive paper. Breaks and gaps in the trails are caused by cloud cover. In this case, the spot was chosen to look out from inside a radio telescope at the Ondrejov Observatory in the Czech Republic. At the end of the exposure, the paper was removed from the can and immediately scanned digitally. Contrasts and colors were then enhanced and added to the digital image. Of course, in December, the Sun trails begin lower down at the northern hemisphere's winter solstice. The trails climb higher in the sky as the June 21st summer solstice approaches.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Agosto 29, 2009, 09:07:18 pm
NGC 7771 Galaxy Group
Credit & Copyright: Kent Biggs
Explanation: Slide your cursor over the image to identify three members of this intriguing gathering of galaxies. Known as the NGC 7771 Group, they lie almost 200 million light-years away toward the high flying constellation Pegasus. The largest galaxy, barred spiral NGC 7771, is itself about 75,000 light-years across, but will someday find itself part of a larger galaxy still. As the galaxies of the group make repeated close passages, they will finally merge into one very large galaxy. Played out over hundreds of millions of years, the process is understood to be a normal part of the evolution of galaxies, including our own Milky Way.

Editor's Note: The labeled version of the image was generated by Astrometry.net.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Agosto 30, 2009, 09:02:06 am
D. rad Bacteria: Candidate Astronauts
Credit: Michael Daly (Uniformed Services University of the Health Sciences), DOE
Explanation: These bacteria could survive on another planet. In an Earth lab, Deinococcus radiodurans (D. rad) survive extreme levels of radiation, extreme temperatures, dehydration, and exposure to genotoxic chemicals. Amazingly, they even have the ability to repair their own DNA, usually with 48 hours. Known as an extremophile, bacteria such as D. rad are of interest to NASA partly because they might be adaptable to help human astronauts survive on other worlds. A recent map of D. rad's DNA might allow biologists to augment their survival skills with the ability to produce medicine, clean water, and oxygen. Already they have been genetically engineered to help clean up spills of toxic mercury. Likely one of the oldest surviving life forms, D. rad was discovered by accident in the 1950s when scientists investigating food preservation techniques could not easily kill it. Pictured above, Deinococcus radiodurans grow quietly in a dish.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Agosto 31, 2009, 08:37:14 am
Open Cluster M25
Credit & Copyright: Jean-Charles Cuillandre (CFHT) & Giovanni Anselmi (Coelum Astronomia), Hawaiian Starlight
Explanation: Many stars like our Sun were formed in open clusters. The above pictured open cluster, M25, contains thousands of stars and is about two thousand light years distant. The stars in this cluster all formed together about 90 million years ago. The bright young stars in M25 appear blue. Open clusters, also called galactic clusters, contain fewer and younger stars than globular clusters. Also unlike globular clusters, open clusters are generally confined to the plane of our Galaxy. M25 is visible with binoculars towards the constellation of the Archer ( Sagittarius).
Título: Re: APOD DO DIA
Enviado por: ahlberto em Setembro 01, 2009, 08:26:24 am
Shadows of Saturn at Equinox
Credit: Cassini Imaging Team, ISS, JPL, ESA, NASA
Explanation: Unusual shadows and dark rings appeared around Saturn near its equinox last month. At that time -- early August -- Saturn's ring plane pointed directly at the Sun. Visible above, Saturn's moon Tethys casts a shadow visible only on the far right. Saturn's own shadow blacks out a large swath of rings on the right. The night side of Saturn glows with ringshine -- sunlight reflected by ring particles back onto Saturn. Images near equinox at Saturn are giving astronomers a chance to search for unexpected shadows that may illuminate previously unknown features of Saturn's complex ring system. Cassini, the robotic spacecraft orbiting Saturn that took this image, is not expected to survive to the next Saturnian equinox in 15 years.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Outubro 29, 2009, 07:58:24 pm
Zodiacal Light Over Laguna Verde
Credit & Copyright: Manel Soria
Explanation: An unusual triangle of light is visible this time of year just before dawn, in the northern hemisphere. Once considered a false dawn, this triangle of light is actually Zodiacal Light, light reflected from interplanetary dust particles. The bright reflecting triangle is clearly visible on the right of the above image taken from Laguna Verde near Valparaíso, Chile in late July. The band of our Milky Way Galaxy on the left mirrors the zodiacal band. Zodiacal dust orbits the Sun predominantly in the same plane as the planets: the ecliptic. Zodiacal light is so bright in the north this time of year because the dust band is oriented nearly vertical at sunrise, so that the thick air near the horizon does not block out relatively bright reflecting dust. Zodiacal light is also bright for people in Earth's northern hemisphere in March and April just after sunset. In the southern hemisphere, zodiacal light is most notable after sunset in late summer, and brightest before sunrise in late spring.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Junho 10, 2010, 12:07:43 am
Orange Sun Simmering
Credit & Copyright: Alan Friedman (Averted Imagination)
Explanation: Even a quiet Sun can be a busy place. And over the deep Solar Minimum of the past few years, our Sun has been unusually quiet. The above image, taken last week in a single color of light called Hydrogen Alpha and then false colored, records a great amount of detail of the simmering surface of our parent star. The gradual brightening towards the Sun's edge in this color-inverted image, called limb darkening, is caused by increased absorption of relatively cool solar gas. Just over the Sun's edges, several prominences are visible, while two prominences on the Sun's face are seen as light streaks just above and right of the image center. Two particularly active areas of the Sun are marked by dark plages. In contrast to recent quiet times, our Sun is moving toward Solar Maximum, and for years will likely appear much more active.
Título: Re: APOD DO DIA
Enviado por: ahlberto em Junho 10, 2010, 09:19:29 am
Regulus and the Red Planet
Image Credit & Copyright: Babak Tafreshi (TWAN)
Explanation: Leo's royal star Regulus and red planet Mars appear in a colorful pairing just above the horizon in this starry skyscape. The photo was taken on June 4th from Oraman, a mountainous region of Kurdistan in western Iran near the border with Iraq. The marked color contrast between Mars and the bright blue star was easy to discern by eye, but is further enhanced in the picture through the use of a diffusion filter. Otherwise dominating the western evening sky, brilliant Venus has already set below the mountains in the scene. Saturn still shines in the night though, farther eastward along the ecliptic plane. Sliding your cursor over the picture will identify the planets, the stars of Leo, and a long-recognized star cluster in Coma Berenices.