The Universe in Super Definition
|
|
|
M 17.jpgM 17 - The "Omega Nebula" detail mgnf116 visiteIn the depths of the dark clouds of dust and molecular gas known as M 17, stars continue to form. Also known as the Omega Nebula and Horseshoe Nebula, the darkness of M17's molecular clouds results from background starlight being absorbed by thick filaments of carbon-based smoke-sized dust. As bright massive stars form, they produce intense and energetic light that slowly boils away the dark shroud. Colors in the above image were picked to highlight specific elements that emit nebular light: red indicates emission from sulfur, green from hydrogen, and blue from oxygen. The Swan Nebula is visible with binoculars towards the constellation of Sagittarius, lies 5000 LY away, and spans 20 LY across.
|
|
M 42 - HST-1.jpgOrion's Nebula an LL Orionis (the "Bow-Shock" effect)61 visiteThis close-up of cosmic clouds and stellar winds features LL Orionis interacting with the Orion Nebula flow. Adrift in Orion's stellar nursery and still in its formative years, variable star LL Orionis produces a wind more energetic than the wind from our own middle-aged Sun.
As the fast stellar wind runs into slow moving gas, a shock front is formed, analogous to the bow wave of a boat moving through water or a plane traveling at supersonic speed.
The small and graceful structure just above and left of center, is LL Ori's "Cosmic Bow Shock", measuring about 1/2 a LY across.
The slower gas is flowing away from the Orion Nebula's hot central star cluster, the Trapezium, located off the upper left corner of the picture.
In 3D, LL Ori's wrap-around shock front is shaped like a bowl that appears brightest when viewed along the bottom edge.
The beautiful picture is part of a large mosaic view of the complex stellar nursery in Orion, filled with a myriad of fluid shapes associated with star formation.
|
|
M 42-PIA08653.jpgMoments of M-4256 visiteThis infrared image from NASA's Spitzer Space Telescope shows the Orion nebula, our closest massive star-making factory, 1,450 light-years from Earth. The nebula is close enough to appear to the naked eye as a fuzzy star in the sword of the popular hunter constellation.
The nebula itself is located on the lower half of the image, surrounded by a ring of dust. It formed in a cold cloud of gas and dust and contains about 1,000 young stars. These stars illuminate the cloud, creating the beautiful nebulosity, or swirls of material, seen here in infrared.
In the center of the nebula (bottom inset of figure 1) are four monstrously massive stars, up to 100,000 times as luminous as our sun, called the Trapezium (tiny yellow smudge to the lower left of green splotches. Radiation and winds from these stars are blasting gas and dust away, excavating a cavity walled in by the large ring of dust.
Behind the Trapezium, still buried deeply in the cloud, a second generation of massive stars is forming (in the area with green splotches). The speckled green fuzz in this bright region is created when bullets of gas shoot out from the juvenile stars and ram into the surrounding cloud.
Above this region of intense activity are networks of cold material that appear as dark veins against the pinkish nebulosity (upper inset pf figure 1). These dark veins contain embryonic stars. Some of the natal stars illuminate the cloud, creating small, aqua-colored wisps. In addition, jets of gas from the stars ram into the cloud, resulting in the green horseshoe-shaped globs.
Spitzer surveyed a significant swath of the Orion constellation, beyond what is highlighted in this image. Within that region, called the Orion cloud complex, the telescope found 2,300 stars circled by disks of planet-forming dust and 200 stellar embryos too young to have developed disks.
This image shows infrared 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.
|
|
M 42-PIA08654-ed.jpgInfrared Orion54 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.
|
|
M 42-PIA08655-ed.jpgThe "Great Cloud" around Orion53 visiteThis image composite shows a part of the Orion constellation surveyed by NASA's Spitzer Space Telescope. The shape of the main image was designed by astronomers to roughly follow the shape of Orion cloud A, an enormous star-making factory containing about 1,800 young stars. This giant cloud includes the famous Orion nebula (bright circular area in "blade" part of hockey stick-shaped box at the bottom), which is visible to the naked eye on a clear, dark night as a fuzzy star in the hunter constellation's sword.
The region that makes up the shaft part of the hockey stick box stretches 70 light-years beyond the Orion nebula. This particular area does not contain massive young stars like those of the Orion nebula, but is filled with 800 stars about the same mass as the sun. These sun-like stars don't live in big "cities," or clusters, of stars like the one in the Orion nebula; instead, they can be found in small clusters (right inset), or in relative isolation (middle insert).
In the right inset, developing stars are illuminating the dusty cloud, creating small wisps that appear greenish. The stars also power speedy jets of gas (also green), which glow as the jets ram into the cloudy material.
Since infrared light can penetrate through dust, we see not only stars within the cloud, but thousands of stars many light-years behind it, which just happen to be in the picture like unwanted bystanders. Astronomers carefully separate the young stars in the Orion cloud complex from the bystanders by looking for their telltale infrared glow.
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.
|
|
M 42-PIA08656.jpgOrion's "Sword"53 visiteThis image composite outlines the region near Orion's sword that was surveyed by NASA's Spitzer Space Telescope (white box). The view on the left (figure 1) is from a visible-light telescope, and the view on the right (figure 2) shows infrared light captured by a previous infrared mission, the Infrared Astronomical Satellite.
The Orion nebula, our closest massive star-making factory, is the brightest spot near the hunter's sword. On a dark night, it can appear to the naked eye as a fuzzy star, and it looks like a ghostly blob through a pair of binoculars. The Orion constellation is one of the most prominent winter constellations, and can be seen from all northern latitudes starting in the fall.
Spitzer used its infrared eyes to probe the dusty clouds of a region called Orion cloud A. outlined here in the hockey stick-shaped box (see PIA08655). This giant cloud stretches almost a quarter of the length of the constellation, an area equivalent to 18 full moons. The small box within the hockey stick shows the location of another image released by Spitzer (see PIA08653), which mainly features the Orion nebula itself.
The bright spot that shows up in the infrared view in the area of Orion's belt is known as Orion cloud B. Together, Orion clouds A and B make up the Orion cloud complex. In a survey of this entire complex, Spitzer unearthed 2,300 stars circled by disks of planet-forming dust and 200 stellar embryos too young to have developed disks.
The Infrared Astronomical Satellite was a joint effort between NASA, the Science and Engineering Research Council, United Kingdom and the Netherlands Agency for Aerospace Programmes, the Netherlands. Spitzer has extended the legacy of the satellite by providing much better resolution and sensitivity.
The visible-light image comes courtesy of Howard McCallon of the Infrared Processing and Analysis Center at the California Institute of Technology of Pasadena.
|
|
M 42.jpgM 42 in different colors167 visiteUna suggestiva combinazione di immagini ottenute con 3 filtri distinti, ciascuno capace di registrare una diversa linea di emissione: Zolfo (S), Ossigeno (O2) e Idrogeno (H). A bassa densità (ovvero nelle condizioni esistenti all'interno della Grande Nebulosa di Orione), S ed H emettono luce rossa mentre l'O2 emette luce verde. Per distinguerli bene nell'immagine, tuttavia, allo Zolfo è stato - in sede di sviluppo finale - assegnato il rosso, all'Idrogeno il verde ed all'Ossigeno il blu.
Il risultato, sebbene la colorazione finale NON sia "realistica", appare comunque non solo utile a fini della ricerca e dell'esatta mappatura dei gas presenti nella Nebulosa, ma anche molto suggestivo.
|
|
M 42~0.jpgM 42 in real colors141 visiteUna visione ad HD della Grande Nebulosa di Orione: visibile nei nostri cieli invernali anche ad occhio nudo, ma in forma di gran lunga meno spettacolare rispetto a quanto ci è dato vedere in questa ed in altre immagini similari. Ma cos'è che permette alla splendida Grande Nebulosa di Orione di manifestarsi così come noi la vediamo? La "fonte" dello splendore della Nebulosa è dato dal "Trapezio": un gruppo di 4 stelle, le più luminose presenti nella nebulosa. Le strutture a "filamento" che rendono la Nebulosa ancora più suggestiva alla vista sono il prodotto di "onde d'urto" (ovvero di "collisioni" vere e proprie fra elementi pesanti - e che si muovono velocemente nello spazio - con gas stazionari o anch'essi in movimento, ma più lentamente rispetto ai primi). La Grande Nebulosa di Orione si estende nello spazio interstellare per oltre 40 AL e si trova ad una distanza da noi pari a circa 1500 AL, comunque all'interno del medesimo braccio della Via Lattea in cui si trova il nostro Sole (e noi con esso).
|
|
M 42~3.jpgM 42 - In Memory Of IRAS (infrared vision)126 visiteCaption NASA originale:"Do you recognize the constellation Orion? This striking but unfamiliar looking picture of the familiar Orion region of the sky was produced using survey data from the now-defunct InfraRed Astronomical Satellite (IRAS). The above image combines information recorded at three different invisible infrared wavelengths and covers about 30x24° on the sky. Most of Orion's visually impressive stars don't stand out, but bright Betelgeuse does appear as a small bright purplish dot on the lower left. The bright region on the right contains the Great Nebula in Orion, while the bright region just above the image bottom is the Rosette Nebula. Surrounding these regions are a jumble of chaotic glowing gas and dark dust jettisoned by stars forming and exploding over millions of years".
|
|
M 45 - PIA08260.jpgM 45 - The "Seven Sisters", from Cassini53 visiteCaption NASA originale:"The stars of the Pleiades cluster, also known by the names "M 45" and "The Seven Sisters," shine brightly in this view from the Cassini spacecraft. The cluster is comprised of hundreds of stars, a few of which are visible to the unaided eye on Earth as a brilliant grouping in the constellation Taurus.
Some faint nebulous material is seen here. This reflection nebula is dust that reflects the light of the hot, blue stars in the cluster.
The monochrome view was made by combining 49 clear filter images of the Pleiades taken with the Cassini spacecraft wide-angle camera on Aug. 1, 2006. The images were taken as a part of a sequence designed to help calibrate the camera electronics".
|
|
M 55.jpgM 55 - Globular Star Cluster60 visiteM 55 is a large Globular Star Cluster of around 100.000 stars. Only 20.000 LY away in the constellation Sagittarius, M 55 appears to earth-bound observers to be nearly 2/3 the size of the full Moon. Globular star clusters like M 55 roam the halo of our Milky Way Galaxy as gravitationally bound populations of stars known to be much older than stellar groups found in the galactic disk. Astronomers who make detailed studies of globular cluster stars can accurately measure the cluster ages and distances. Their results ultimately constrain the age of the Universe and provide a fundamental rung on the astronomical distance ladder.
|
|
M 64.jpgM 64 (NGC 4826) - Great Spiral Galaxy100 visiteThe "Sleeping Beauty Galaxy" may appear peaceful at first sight but it is actually tossing and turning. In an unexpected twist, recent observations have shown that the gas in the outer regions of this spiral is rotating in the opposite direction from all of the stars! Collisions between gas in the inner and outer regions are creating many hot blue stars and pink emission nebulae. The above image was taken by the Hubble Space Telescope in 2001. The fascinating internal motions of M 64 (also known as NGC 4826), are thought to be the result of a collision between a small galaxy and a large galaxy where the resultant mix has not yet settled down.
|
|
| 157 immagini su 14 pagina(e) |
 |
|
|
5 | |
|
|
|
|
|
|
