Autor Tópico: APOD DO DIA  (Lida 12485 vezes)

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Offline ahlberto

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Re: APOD DO DIA
« Responder #45 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #46 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #47 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
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Offline ahlberto

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Re: APOD DO DIA
« Responder #48 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #49 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #50 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #51 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.
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Re: APOD DO DIA
« Responder #52 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #53 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #54 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #55 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.
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Re: APOD DO DIA
« Responder #56 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.
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Re: APOD DO DIA
« Responder #57 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #58 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.
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Re: APOD DO DIA
« Responder #59 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.
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