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The James Webb Space Telescope

The James Webb Space Telescope

James Webb Space Telescope 3/4 view of JWST from the "top" (opposite side from the Sun). The James Webb Space Telescope (JWST), previously known as Next Generation Space Telescope (NGST), is a planned space telescope optimized for observations in the infrared, and a scientific successor to the Hubble Space Telescope and the Spitzer Space Telescope. The main technical features are a large and very cold 6.5-meter (21 ft) diameter mirror and four specialized instruments at an observing position far from Earth, orbiting the Earth–Sun L2 point. In planning since 1996,[3] the project represents an international collaboration of about 17 countries[4] led by NASA, and with significant contributions from the European Space Agency and the Canadian Space Agency. JWST's capabilities will enable a broad range of investigations across many subfields of astronomy.[6] One particular goal involves observing some of the most distant objects in the Universe, beyond the reach of current ground and space based instruments.

Scientists Now Know: We're From Sagittarius Dwarf Galaxy! Scientists Now Know: We're Not From Here! Summary & comments by Dan Eden for Viewzone "This first full-sky map of Sagittarius shows its extensive interaction with the Milky Way," Majewski said. The study's map of M giants depicts 2 billion years of Sagittarius stripping by the Milky Way, and suggests that Sagittarius has reached a critical phase in what had been a slow dance of death. "After slow, continuous gnawing by the Milky Way, Sagittarius has been whittled down to the point that it cannot hold itself together much longer," said 2MASS Science Team member and study co-author Martin Weinberg of the University of Massachusetts. Does this mean we are at a unique moment in the life of our galaxy? "Whenever possible, astronomers appeal to the principle that we are not at a special time or place in the universe," Majewski said. On the other hand, Majewski and his colleagues have been surprised by the Earth's proximity to a portion of the Sagittarius debris. Implications in Global Warming?

Découverte de trois exoplanètes potentiellement habitables Des astronomes de l'Observatoire européen austral (ESO) ont découvert dans la constellation du Scorpion un système solaire "doté d'une zone habitable bien remplie", avec trois "super-Terres" où les conditions seraient compatibles avec l'existence d'eau liquide. C'est autour de l'étoile Gliese 667C, d'une masse équivalente à un tiers de celle de notre Soleil, que l'équipe a fait cette trouvaille, à l'aide de l'instrument HARPS équipant le télescope de 3,6 mètres de l'ESO au Chili, indique l'organisation dans un communiqué. Le système de trois étoiles auquel appartient Gliese 667C est abondamment étudié par les scientifiques. Non seulement il est dans le voisinage immédiat de notre système solaire (22 années-lumière) mais il est aussi étonnamment similaire. Il représente donc un candidat de choix pour la recherche d'exoplanètes potentiellement habitables. Au total, les astronomes ont donc identifié au moins cinq planètes, deux autres demandant encore à être confirmées.

The James Webb Space Telescope About Webb's Orbit The James Webb Space Telescope will observe primarily the infrared light from faint and very distant objects. But all objects, including telescopes, also emit infrared light. To avoid swamping the very faint astronomical signals with radiation from the telescope, the telescope and its instruments must be very cold. Therefore, Webb has a large shield that blocks the light from the Sun, Earth, and Moon, which otherwise would heat up the telescope, and interfere with the observations. The L2 orbit is an elliptical orbit about the semi-stable second Lagrange point . In three of the solutions found by Lagrange, the bodies are in line (L1, L2, and L3); in the other two, the bodies are at the points of equilateral triangles (L4 and L5). In the case of Webb, the 3 bodies involved are the Sun, the Earth and the Webb. Other infrared missions have selected an L2 orbit, like WMAP and H2L2. Here are a few graphics that illustrate how far away Webb will be.

Dawn Captures Sharper Images of Ceres Craters and mysterious bright spots are beginning to pop out in the latest images of Ceres from NASA's Dawn spacecraft. These images, taken Feb. 12 at a distance of 52,000 miles (83,000 kilometers) from the dwarf planet, pose intriguing questions for the science team to explore as the spacecraft nears its destination. The image is available at: "As we slowly approach the stage, our eyes transfixed on Ceres and her planetary dance, we find she has beguiled us but left us none the wiser," said Chris Russell, principal investigator of the Dawn mission, based at UCLA. Dawn will be gently captured into orbit around Ceres on March 6. The spacecraft explored the giant asteroid Vesta for 14 months during 2011 and 2012. Dawn's mission to Vesta and Ceres is managed by the Jet Propulsion Laboratory for NASA's Science Mission Directorate in Washington. For more information about Dawn, visit: Media Contact

Les plus grands telescopes du monde Liste | Explications Légendes du tableau : Remarque : le télescope spatial Hubble "ne fait que" 2.4 mètres de diamètre mais il bénéficie de conditions exeptionnelles car il se trouve dans l'espace. Explications Le choix du site, la latitude et l'altitude Le choix du site est très important car il dertermine pour beaucoup la qualité des images que le télescope va fournir. Le diamètre Il détermine la puissance des télescopes. La mise en service Les 13 plus grands télescopes ont été mis en service il y a moins de 10 ans. L'appartenance Ce sont les pays ou groupes de pays les plus puissants de la planète qui constuisent les plus grands télescopes (Etats-Unis, Europe et Japon). Voir aussi : Les plus grandes lunettes astronomiques du monde Les lunettes astronomiques et les télescopes Source pour la liste : le grand livre du Ciel chez Bordas

The Fermi Gamma-ray Space Telescope Galaxy Zoo Hubble Goes to the eXtreme to Assemble Farthest-Ever View of the Universe Hubble Goes to the eXtreme to Assemble Farthest-Ever View of the Universe Like photographers assembling a portfolio of best shots, astronomers have assembled a new, improved portrait of mankind's deepest-ever view of the universe. (Credit: NASA; ESA; G. Illingworth, D. Magee, and P. Called the eXtreme Deep Field, or XDF, the photo was assembled by combining 10 years of NASA Hubble Space Telescope photographs taken of a patch of sky at the center of the original Hubble Ultra Deep Field. The Hubble Ultra Deep Field is an image of a small area of space in the constellation Fornax, created using Hubble Space Telescope data from 2003 and 2004. The new full-color XDF image is even more sensitive, and contains about 5,500 galaxies even within its smaller field of view. Magnificent spiral galaxies similar in shape to our Milky Way and the neighboring Andromeda galaxy appear in this image, as do the large, fuzzy red galaxies where the formation of new stars has ceased. Related Link

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