Autor Tópico: APOD DO DIA  (Lida 12624 vezes)

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Offline ahlberto

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Re: APOD DO DIA
« Responder #75 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #76 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
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Offline ahlberto

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Re: APOD DO DIA
« Responder #77 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #78 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #79 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #80 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).
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Offline ahlberto

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Re: APOD DO DIA
« Responder #81 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #82 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #83 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.
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Offline ahlberto

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Re: APOD DO DIA
« Responder #84 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.
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