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002-vg2_2670443.jpg002-Approaching Uranus...60 visite
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005-vg2_2686312.jpg016-Uranus' Fly-By (2)60 visite
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m10_aom_3_a.jpg60 visitenessun commento
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m10_aom_18.jpgMercury's "Inbound" view and Kuiper Crater60 visiteThis is a mosaic of images taken of Mercury taken from 125.000 miles away. The tiny, brightly rayed crater (just below center top) was the first recognizable feature on the Planet's surface and was named in memory of astronomer Gerard Kuiper, a Mariner 10 team member.
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M 42-PIA08654-ed.jpgInfrared Orion60 visiteThis image composite compares infrared and visible views of the famous Orion nebula and its surrounding cloud, an industrious star-making region located near the hunter constellation's sword. The infrared picture is from NASA's Spitzer Space Telescope, and the visible image is from the National Optical Astronomy Observatory, headquartered in Tucson, Ariz.
In addition to Orion, two other nebulas can be seen in both pictures. The Orion nebula, or M42, is the largest and takes up the lower half of the images; the small nebula to the upper left of Orion is called M43; and the medium-sized nebula at the top is NGC 1977. Each nebula is marked by a ring of dust that stands out in the infrared view. These rings make up the walls of cavities that are being excavated by radiation and winds from massive stars. The visible view of the nebulas shows gas heated by ultraviolet radiation from the massive stars.
Above the Orion nebula, where the massive stars have not yet ejected much of the obscuring dust, the visible image appears dark with only a faint glow. In contrast, the infrared view penetrates the dark lanes of dust, revealing bright swirling clouds and numerous developing stars that have shot out jets of gas (green). This is because infrared light can travel through dust, whereas visible light is stopped short by it.
The infrared image shows light captured by Spitzer's infrared array camera. Light with wavelengths of 8 and 5.8 microns (red and orange) comes mainly from dust that has been heated by starlight. Light of 4.5 microns (green) shows hot gas and dust; and light of 3.6 microns (blue) is from starlight.
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Black Hole-PIA08697_fig1.jpgBlack Holes60 visiteThis diagram illustrates research from NASA's Galaxy Evolution Explorer showing that black holes -- once they reach a critical size -- can put the brakes on new star formation in elliptical galaxies.
In this graph, galaxies and their supermassive black holes are indicated by the drawings (the black circle at the center of each galaxy represents the black hole). The relative masses of the galaxies and their black holes are reflected in the sizes of the drawings. Blue indicates that the galaxy has new stars, while red means the galaxy does not have any detectable new stars.
The Galaxy Evolution Explorer observed the following trend: the biggest galaxies and black holes (shown in upper right corner) are more likely to have no observable star formation (red) than the smaller galaxies with smaller black holes. This is evidence that black holes can create environments unsuitable for stellar birth.
The white line in the diagram illustrates that, for any galaxy no matter what the mass, its black hole must reach a critical size before it can shut down star formation.
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Black Hole-PIA08696.jpgBlack Hole60 visiteThis artist's concept depicts a supermassive black hole at the center of a galaxy. NASA's Galaxy Evolution Explorer found evidence that black holes -- once they grow to a critical size -- stifle the formation of new stars in elliptical galaxies. Black holes are thought to do this by heating up and blasting away the gas that fuels star formation.
The blue color here represents radiation pouring out from material very close to the black hole. The grayish structure surrounding the black hole, called a torus, is made up of gas and dust. Beyond the torus, only the old red-colored stars that make up the galaxy can be seen. There are no new stars in the galaxy.
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APOLLO 11 AS 11-40-5878-A.jpgAS 11-40-5878 - A "small step for a Man"...60 visite
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APOLLO 12 AS 12-48-7100.jpgAS 12-48-7100 - Surveyor III!60 visiteCaption NASA originale:"Surveyor III and the LM. The TV camera is the vertical cylinder to the right of the solar-panel mast and the scoop can be seen extended out to the right. The Surveyor landed on a slope and bounced and slid a short way before coming to rest. Visual evidence comes from the left-hand footpad, which is dug into the soil, and the foreground footpad, which made 2 distinct imprints nearer us before coming to rest. The Surveyor III scoop was designed by Caltech Prof. of Engin.ing R. Scott".
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AS09-19-2968.jpgAS 09-19-2968 - Mother Earth60 visite
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AS10-27-3893.jpgAS 10-27-3893 - The "Dawn of a New Era"60 visitenessun commento
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Comets-Comet_SWAN-2.jpgComet SWAN60 visiteCaption NASA originale:"Near its closest approach to planet Earth, comet SWAN (C/2006 M4) brightened unexpectedly earlier this week, becoming visible to naked-eye observers under dark night skies. Telescopic observers also noticed dramatic changes in the comet's colorful coma and tail, seen in this view recorded on October 25th, 2006.
To make the picture, images totaling eight minutes in exposure time were stacked and centered on the comet as it moved relatively quickly against the background star field. The picture covers about 1° of the sky.
Northern Hemisphere observers should still find the comet an easy binocular target in the early evening, even though moonlight will increase the overall sky brightness in the next few days.
Look toward the North-Western horizon and the Constellation Hercules".
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