Les plus belles images de Hubble. Le télescope spatial a redessiné les frontière de notre univers. Il nous a offert au fil des années des images à couper le souffle qui ont repoussé les frontières de nos connaissances scientifiques. Vous pouvez télécharger gratuitement l’ebook des vingt-cinq ans de hubble
NASA’s Hubble Space has peered nearly 5 billion light-years away to resolve intricate details in the galaxy cluster Abell 370. This object is one of the very first galaxy clusters where astronomers observed the phenomenon of gravitational lensing, where the warping of space by the cluster’s gravitational field distorts the light from galaxies lying far behind it. This is manifested as arcs and streaks in the picture, which are the stretched images of background galaxies. Gravitational lensing proves a vital tool for astronomers when measuring the dark matter distribution in massive clusters, since the mass distribution can be reconstructed from its gravitational effects. Galaxy clusters are the most massive structures of the universe, located at the crossing of the filaments of the cosmic web of dark matter. The most massive clusters can contain up to 1,000 galaxies and intergalactic hot gas, all held together primarily by the gravity of dark matter.
A delicate sphere of gas, photographed by NASA’s Hubble Space Telescope, floats serenely in the depths of space. The pristine shell, or bubble, is the result of gas that is being shocked by the expanding blast wave from a supernova. Called SNR 0509-67.5 (or SNR 0509 for short), the bubble is the visible remnant of a powerful stellar explosion in the Large Magellanic Cloud (LMC), a small galaxy about 160,000 light-years from Earth. Ripples in the shell’s surface may be caused by either subtle variations in the density of the ambient interstellar gas, or possibly driven from the interior by pieces of the ejecta. The bubble-shaped shroud of gas is 23 light-years across and is expanding at more than 11 million miles per hour (5,000 kilometers per second). Astronomers have concluded that the explosion was one of an especially energetic and bright variety of supernovae. Known as Type Ia, such supernova events are thought to result from a white dwarf star in a binary system that robs its partner of material, takes on much more mass than it is able to handle, and eventually explodes. Hubble’s Advanced Camera for Surveys observed the supernova remnant on Oct. 28, 2006, with a filter that isolates light from glowing hydrogen seen in the expanding shell. These observations were then combined with visible-light images of the surrounding star field that were imaged with Hubble’s Wide Field Camera 3 on Nov. 4, 2010. With an age of about 400 years as seen from Earth, the supernova might have been visible to southern hemisphere observers around the year 1600. However, there are no known records of a "new star" in the direction of the LMC near that time. A more recent supernova in the LMC, SN 1987A, did catch the eye of Earth viewers and continues to be studied with ground- and space-based telescopes, including Hubble.
NASA’s Hubble Space Telescope has trained its razor-sharp eye on one of the universe’s most stately and photogenic galaxies, the Sombrero galaxy, Messier 104 (M104). The galaxy’s hallmark is a brilliant white, bulbous core encircled by the thick dust lanes comprising the spiral structure of the galaxy. As seen from Earth, the galaxy is tilted nearly edge-on. We view it from just six degrees north of its equatorial plane. This brilliant galaxy was named the Sombrero because of its resemblance to the broad rim and high-topped Mexican hat. At a relatively bright magnitude of +8, M104 is just beyond the limit of naked-eye visibility and is easily seen through small telescopes. The Sombrero lies at the southern edge of the rich Virgo cluster of galaxies and is one of the most massive objects in that group, equivalent to 800 billion suns. The galaxy is 50,000 light-years across and is located 28 million light-years from Earth. Hubble easily resolves M104’s rich system of globular clusters, estimated to be nearly 2,000 in number – 10 times as many as orbit our Milky Way galaxy. The ages of the clusters are similar to the clusters in the Milky Way, ranging from 10-13 billion years old. Embedded in the bright core of M104 is a smaller disk, which is tilted relative to the large disk. X-ray emission suggests that there is material falling into the compact core, where a 1-billion-solar-mass black hole resides. In the 19th century, some astronomers speculated that M104 was simply an edge-on disk of luminous gas surrounding a young star, which is prototypical of the genesis of our solar system. But in 1912, astronomer V. M. Slipher discovered that the hat-like object appeared to be rushing away from us at 700 miles per second. This enormous velocity offered some of the earliest clues that the Sombrero was really another galaxy, and that the universe was expanding in all directions. The Hubble Heritage Team took these observations in M
Astronomers using NASA’s Hubble Space Telescope have assembled a comprehensive picture of the evolving universe ? among the most colorful deep space images ever captured by the 24-year-old telescope. Researchers say the image, from a new study called the Ultraviolet Coverage of the Hubble Ultra Deep Field, provides the missing link in star formation. The Hubble Ultra Deep Field 2014 image is a composite of separate exposures taken in 2002 to 2012 with Hubble’s Advanced Camera for Surveys and Wide Field Camera 3. Astronomers previously studied the Hubble Ultra Deep Field (HUDF) in visible and near-infrared light in a series of images captured from 2003 to 2009. The HUDF shows a small section of space in the southern-hemisphere constellation Fornax. Now, using ultraviolet light, astronomers have combined the full range of colors available to Hubble, stretching all the way from ultraviolet to near-infrared light. The resulting image – made from 841 orbits of telescope viewing time – contains approximately 10,000 galaxies, extending back in time to within a few hundred million years of the big bang. Prior to the Ultraviolet Coverage of the Hubble Ultra Deep Field study of the universe, astronomers were in a curious position. Missions such as NASA’s Galaxy Evolution Explorer (GALEX) observatory, which operated from 2003 to 2013, provided significant knowledge of star formation in nearby galaxies. Using Hubble’s near-infrared capability, researchers also studied star birth in the most distant galaxies, which appear to us in their most primitive stages due to the significant amount of time required for the light of distant stars to travel into a visible range. But for the period in between, when most of the stars in the universe were born – a distance extending from about 5 billion to 10 billion light-years – they did not have enough data. « The lack of information from ultraviolet light made studying galaxies in the HUDF like trying to understand the history of families wi
Jupiter’s monster storm, the Great Red Spot, was once so large that three Earths would fit inside it. But new measurements by NASA’s Hubble Space Telescope reveal that the largest storm in our solar system has downsized significantly. The red spot, which has been raging for at least a hundred years, is only the width of one Earth. What is happening? One possibility is that some unknown activity in the planet’s atmosphere may be draining energy and weakening the storm, causing it to shrink.
Tis the season for holiday decorating and tree-trimming. Not to be left out, astronomers using NASA’s Hubble Space Telescope have photographed a festive-looking nearby planetary nebula called NGC 5189. The intricate structure of this bright gaseous nebula resembles a glass-blown holiday ornament with a glowing ribbon entwined. Planetary nebulae represent the final brief stage in the life of a medium-sized star like our Sun. While consuming the last of the fuel in its core, the dying star expels a large portion of its outer envelope. This material then becomes heated by the radiation from the stellar remnant and radiates, producing glowing clouds of gas that can show complex structures, as the ejection of mass from the star is uneven in both time and direction. A spectacular example of this beautiful complexity is seen in the bluish lobes of NGC 5189. Most of the nebula is knotty and filamentary in its structure. As a result of the mass-loss process, the planetary nebula has been created with two nested structures, tilted with respect to each other, that expand away from the center in different directions. This double bipolar or quadrupolar structure could be explained by the presence of a binary companion orbiting the central star and influencing the pattern of mass ejection during its nebula-producing death throes. The remnant of the central star, having lost much of its mass, now lives its final days as a white dwarf. However, there is no visual candidate for the possible companion. The bright golden ring that twists and tilts through the image is made up of a large collection of radial filaments and cometary knots. These are usually formed by the combined action of photo-ionizing radiation and stellar winds. This image was taken with Hubble’s Wide Field Camera 3 on July 6, 2012, in filters tuned to the specific colors of fluorescing sulfur, hydrogen, and oxygen atoms. Broad filters in the visible and near-infrared were used to capture the star c
This new image taken with NASA’s Hubble Space Telescope depicts bright, blue, newly formed stars that are blowing a cavity in the center of a star-forming region in the Small Magellanic Cloud. At the heart of the star-forming region, lies star cluster NGC 602. The high-energy radiation blazing out from the hot young stars is sculpting the inner edge of the outer portions of the nebula, slowly eroding it away and eating into the material beyond. The diffuse outer reaches of the nebula prevent the energetic outflows from streaming away from the cluster. Ridges of dust and gaseous filaments are seen towards the northwest (in the upper-left part of the image) and towards the southeast (in the lower right-hand corner). Elephant trunk-like dust pillars point towards the hot blue stars and are tell-tale signs of their eroding effect. In this region it is possible with Hubble to trace how the star formation started at the center of the cluster and propagated outward, with the youngest stars still forming today along the dust ridges. The Small Magellanic Cloud, in the constellation Tucana, is roughly 200,000 light-years from the Earth. Its proximity to us makes it an exceptional laboratory to perform in-depth studies of star formation processes and their evolution in an environment slightly different from our own Milky Way. Dwarf galaxies such as the Small Magellanic Cloud, with significantly fewer stars compared to our own galaxy, are considered to be the primitive building blocks of larger galaxies. The study of star formation within this dwarf galaxy is particularly interesting to astronomers because its primitive nature means that it lacks a large percentage of the heavier elements that are forged in successive generations of stars through nuclear fusion. These observations were taken with Hubble’s Advanced Camera for Surveys in July 2004. Filters that isolate visible and infrared light were combined with a filter that samples the hydrogen and nitrogen emission f
NASA’s Hubble Space Telescope has imaged a glittering collection of stars. The cluster is surrounded by clouds of interstellar gas and dust-the raw material for new star formation. The nebula, located 20,000 light-years away in the constellation Carina, contains a central cluster of huge, hot stars, called NGC 3603. This environment is not as peaceful as it looks. Ultraviolet radiation and violent stellar winds have blown out an enormous cavity in the gas and dust enveloping the cluster, providing an unobstructed view of the cluster. NGC 3603 contains some of the most massive stars known. These huge stars live fast and die young, burning through their hydrogen fuel quickly and ultimately ending their lives in supernova explosions. Star clusters like NGC 3603 provide important clues to understanding the origin of massive star formation in the early, distant universe.
A photogenic and favorite target for amateur astronomers, the full beauty of nearby spiral galaxy M83 is unveiled in all of its glory in this Hubble Space Telescope mosaic image. The vibrant magentas and blues reveal the galaxy is ablaze with star formation. The galaxy, also known as the Southern Pinwheel, lies 15 million light-years away in the constellation Hydra. The Hubble photograph captures thousands of star clusters, hundreds of thousands of individual stars, and « ghosts » of dead stars called supernova remnants. The galactic panorama unveils a tapestry of the drama of stellar birth and death spread across 50,000 light-years. The newest generations of stars are forming largely in clusters on the edges of the dark spiral dust lanes. These brilliant young stellar groupings, only a few million years old, produce huge amounts of ultraviolet light that is absorbed by surrounding diffuse gas clouds, causing them to glow in pinkish hydrogen light. Gradually, the fierce stellar winds from the youngest, most massive stars blow away the gas, revealing bright blue star clusters and giving a « Swiss Cheese » appearance to the spiral arms. These youngest star clusters are about 1 million to 10 million years old. The populations of stars up to 100 million years or older appear yellow or orange by comparison because the young blue stars have already burned out. Interstellar « bubbles » produced by nearly 300 supernovas from massive stars have been found in this Hubble image. By studying these supernova remnants, astronomers can better understand the nature of the stars that exploded and dispersed nuclear processed chemical elements back into the galaxy, contributing to the next generation of new stars. This image is being used to support a citizen science project titled STAR DATE: M83. The primary goal is to estimate ages for approximately 3,000 star clusters. Amateur scientists will use the presence or absence of the pink hydrogen emission, the sharpness
This is a mosaic image, one of the largest ever taken by NASA’s Hubble Space Telescope of the Crab Nebula, a six-light-year-wide expanding remnant of a star’s supernova explosion. Japanese and Chinese astronomers recorded this violent event nearly 1,000 years ago in 1054, as did, almost certainly, Native Americans. The orange filaments are the tattered remains of the star and consist mostly of hydrogen. The rapidly spinning neutron star embedded in the center of the nebula is the dynamo powering the nebula’s eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second due to the neutron star’s rotation. A neutron star is the crushed ultra-dense core of the exploded star. The Crab Nebula derived its name from its appearance in a drawing made by Irish astronomer Lord Rosse in 1844, using a 36-inch telescope. When viewed by Hubble, as well as by large ground-based telescopes such as the European Southern Observatory’s Very Large Telescope, the Crab Nebula takes on a more detailed appearance that yields clues into the spectacular demise of a star, 6,500 light-years away. The newly composed image was assembled from 24 individual Wide Field and Planetary Camera 2 exposures taken in October 1999, January 2000, and December 2000. The colors in the image indicate the different elements that were expelled during the explosion. Blue in the filaments in the outer part of the nebula represents neutral oxygen, green is singly-ionized sulfur, and red indicates doubly-ionized oxygen.
« Starry Night, » Vincent van Gogh’s famous painting, is renowned for its bold whorls of light sweeping across a raging night sky. Although this image of the heavens came only from the artist’s restless imagination, a new picture from NASA’s Hubble Space Telescope bears remarkable similarities to the van Gogh work, complete with never-before-seen spirals of dust swirling across trillions of miles of interstellar space. This image, obtained with the Advanced Camera for Surveys on February 8, 2004, is Hubble’s latest view of an expanding halo of light around a distant star, named V838 Monocerotis (V838 Mon). The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a flashbulb-like pulse of light two years ago. V838 Mon is located about 20,000 light-years away from Earth in the direction of the constellation Monoceros, placing the star at the outer edge of our Milky Way galaxy. Called a light echo, the expanding illumination of a dusty cloud around the star has been revealing remarkable structures ever since the star suddenly brightened for several weeks in early 2002. Though Hubble has followed the light echo in several snapshots, this new image shows swirls or eddies in the dusty cloud for the first time. These eddies are probably caused by turbulence in the dust and gas around the star as they slowly expand away. The dust and gas were likely ejected from the star in a previous explosion, similar to the 2002 event, which occurred some tens of thousands of years ago. The surrounding dust remained invisible and unsuspected until suddenly illuminated by the brilliant explosion of the central star two years ago. The Hubble telescope has imaged V838 Mon and its light echo several times since the star’s outburst in January 2002, in order to follow the constantly changing appearance of the dust as the pulse of illumination continues to expand away from the star at the speed
Several million young stars are vying for attention in this NASA Hubble Space Telescope image of a raucous stellar breeding ground in 30 Doradus, located in the heart of the Tarantula Nebula. Early astronomers nicknamed the nebula because its glowing filaments resemble spider legs. 30 Doradus is the brightest star-forming region visible in a neighboring galaxy and home to the most massive stars ever seen. The nebula resides 170,000 light-years away in the Large Magellanic Cloud, a small, satellite galaxy of our Milky Way. No known star-forming region in our galaxy is as large or as prolific as 30 Doradus. The composite image comprises one of the largest mosaics ever assembled from Hubble photos and includes observations taken by Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys. The Hubble image is combined with ground-based data of the Tarantula Nebula, taken with the European Southern Observatory’s 2.2-meter telescope in La Silla, Chile. NASA and the Space Telescope Science Institute are releasing the image to celebrate Hubble’s 22nd anniversary. Collectively, the stars in this image are millions of times more massive than our Sun. The image is roughly 650 light-years across and contains some rambunctious stars, from one of the fastest rotating stars to the speediest and most massive runaway star. The nebula is close enough to Earth that Hubble can resolve individual stars, giving astronomers important information about the stars’ birth and evolution. Many small galaxies have more spectacular starbursts, but the Large Magellanic Cloud’s 30 Doradus is one of the only extragalactic star-forming regions that astronomers can study in so much detail. The star-birthing frenzy in 30 Doradus may be partly fueled by its close proximity to its companion galaxy, the Small Magellanic Cloud. The image reveals the stages of star birth, from embryonic stars a few thousand years old still wrapped in cocoons of dark gas to behemoths that die young in
NASA’s Hubble Space Telescope snapped this image of the planetary nebula, catalogued as NGC 6302, but more popularly called the Bug Nebula or the Butterfly Nebula. What resemble dainty butterfly wings are actually roiling cauldrons of gas heated to more than 36,000 degrees Fahrenheit. The gas is tearing across space at more than 600,000 miles an hour. A dying star that was once about five times the mass of the Sun is at the center of this fury. It has ejected its envelope of gases and is now unleashing a stream of ultraviolet radiation that is making the cast-off material glow. This object is an example of a planetary nebula, so-named because many of them have a round appearance resembling that of a planet when viewed through a small telescope. NGC 6302 lies within our Milky Way galaxy, roughly 3,800 light-years away in the constellation Scorpius. The glowing gas is the star’s outer layers, expelled over about 2,200 years. The « butterfly » stretches for more than two light-years, which is about half the distance from the Sun to the nearest star, Alpha Centauri.
In celebration of the 17th anniversary of the launch and deployment of NASA’s Hubble Space Telescope, a team of astronomers is releasing one of the largest panoramic images ever taken with Hubble’s cameras. It is a 50-light-year-wide view of the central region of the Carina Nebula where a maelstrom of star birth – and death – is taking place. Hubble’s view of the nebula shows star birth in a new level of detail. The fantasy-like landscape of the nebula is sculpted by the action of outflowing winds and scorching ultraviolet radiation from the monster stars that inhabit this inferno. In the process, these stars are shredding the surrounding material that is the last vestige of the giant cloud from which the stars were born. The immense nebula contains at least a dozen brilliant stars that are roughly estimated to be at least 50 to 100 times the mass of our Sun. The most unique and opulent inhabitant is the star Eta Carinae, at far left. Eta Carinae is in the final stages of its brief and eruptive lifespan, as evidenced by two billowing lobes of gas and dust that presage its upcoming explosion as a titanic supernova. The fireworks in the Carina region started three million years ago when the nebula’s first generation of newborn stars condensed and ignited in the middle of a huge cloud of cold molecular hydrogen. Radiation from these stars carved out an expanding bubble of hot gas. The island-like clumps of dark clouds scattered across the nebula are nodules of dust and gas that are resisting being eaten away by photoionization. The hurricane blast of stellar winds and blistering ultraviolet radiation within the cavity is now compressing the surrounding walls of cold hydrogen. This is triggering a second stage of new star formation. Our Sun and our solar system may have been born inside such a cosmic crucible 4.6 billion years ago. In looking at the Carina Nebula we are seeing the genesis of star making as it commonly occurs along the dense spiral
In celebration of the 24th anniversary of the launch of NASA’s Hubble Space Telescope (on April 24, 1990) astronomers have taken an infrared-light portrait of a roiling region of starbirth located 6,400 light-years away. The Hubble mosaic unveils a collection of carved knots of gas and dust in a small portion of the Monkey Head Nebula (also known as NGC 2174 and Sharpless Sh2-252). The nebula is a star-forming region that hosts dusky dust clouds silhouetted against glowing gas. Massive, newly formed stars near the center of the nebula (and toward the right in this image) are blasting away at dust within the nebula. Ultraviolet light from these bright stars helps carve the dust into giant pillars. The nebula is mostly composed of hydrogen gas, which becomes ionized by the ultraviolet radiation. As the interstellar dust particles are warmed from the radiation from the stars in the center of the nebula, they heat up and begin to glow at infrared wavelengths. The image demonstrates Hubble’s powerful infrared vision and offers a tantalizing hint of what scientists can expect from the upcoming James Webb Space Telescope. Observations of NGC 2174 were taken in February 2014. For more information, contact: Ray Villard Space Telescope Science Institute, Baltimore, Md. 410-338-4514 email@example.com
In this detailed view from NASA’s Hubble Space Telescope, the so-called Cat’s Eye Nebula looks like the penetrating eye of the disembodied sorcerer Sauron from the film adaptation of « The Lord of the Rings. » The nebula, formally cataloged NGC 6543, is every bit as inscrutable as the J.R.R. Tolkien phantom character. Though the Cat’s Eye Nebula was one of the first planetary nebulae to be discovered, it is one of the most complex such nebulae seen in space. A planetary nebula forms when Sun-like stars gently eject their outer gaseous layers that form bright nebulae with amazing and confounding shapes. In 1994, Hubble first revealed NGC 6543’s surprisingly intricate structures, including concentric gas shells, jets of high-speed gas, and unusual shock-induced knots of gas. As if the Cat’s Eye itself isn’t spectacular enough, this new image taken with Hubble’s Advanced Camera for Surveys (ACS) reveals the full beauty of a bull’s eye pattern of eleven or even more concentric rings, or shells, around the Cat’s Eye. Each ‘ring’ is actually the edge of a spherical bubble seen projected onto the sky – that’s why it appears bright along its outer edge. Observations suggest the star ejected its mass in a series of pulses at 1,500-year intervals. These convulsions created dust shells, each of which contain as much mass as all of the planets in our solar system combined (still only one percent of the Sun’s mass). These concentric shells make a layered, onion-skin structure around the dying star. The view from Hubble is like seeing an onion cut in half, where each skin layer is discernible. Until recently, it was thought that such shells around planetary nebulae were a rare phenomenon. However, Romano Corradi (Isaac Newton Group of Telescopes, Spain) and collaborators, in a paper published in the European journal Astronomy and Astrophysics in April 2004, have instead shown that the formation of these rings is likely to be the rule rather than the exception. The bull’s-eye patt
This long-exposure Hubble Space Telescope image of massive galaxy cluster Abell 2744 is the deepest ever made of any cluster of galaxies. It shows some of the faintest and youngest galaxies ever detected in space. Abell 2744, located in the constellation Sculptor, appears in the foreground of this image. It contains several hundred galaxies as they looked 3.5 billion years ago. The immense gravity in Abell 2744 acts as a gravitational lens to warp space and brighten and magnify images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did longer than 12 billion years ago, not long after the big bang. This image is part of an unprecedented long-distance view of the universe from an ambitious collaborative project among the NASA Great Observatories called The Frontier Fields. Over the next several years select patches of the sky will be photographed for the purpose of better understanding galaxy evolution. This visible-light and near-infrared composite image was taken with the Wide Field Camera 3.
This new NASA Hubble Space Telescope image of the Antennae galaxies is the sharpest yet of this merging pair of galaxies. During the course of the collision, billions of stars will be formed. The brightest and most compact of these star birth regions are called super star clusters. The two spiral galaxies started to interact a few hundred million years ago, making the Antennae galaxies one of the nearest and youngest examples of a pair of colliding galaxies. Nearly half of the faint objects in the Antennae image are young clusters containing tens of thousands of stars. The orange blobs to the left and right of image center are the two cores of the original galaxies and consist mainly of old stars criss-crossed by filaments of dust, which appears brown in the image. The two galaxies are dotted with brilliant blue star-forming regions surrounded by glowing hydrogen gas, appearing in the image in pink. The new image allows astronomers to better distinguish between the stars and super star clusters created in the collision of two spiral galaxies. By age dating the clusters in the image, astronomers find that only about 10 percent of the newly formed super star clusters in the Antennae will survive beyond the first 10 million years. The vast majority of the super star clusters formed during this interaction will disperse, with the individual stars becoming part of the smooth background of the galaxy. It is however believed that about a hundred of the most massive clusters will survive to form regular globular clusters, similar to the globular clusters found in our own Milky Way galaxy. The Antennae galaxies take their name from the long antenna-like « arms » extending far out from the nuclei of the two galaxies, best seen by ground-based telescopes. These « tidal tails » were formed during the initial encounter of the galaxies some 200 to 300 million years ago. They give us a preview of what may happen when our Milky Way galaxy will collide with the neighboring Andromeda g
In celebration of the 21st anniversary of the Hubble Space Telescope’s deployment into space, astronomers at the Space Telescope Science Institute in Baltimore, Md., pointed Hubble’s eye to an especially photogenic group of interacting galaxies called Arp 273. The larger of the spiral galaxies, known as UGC 1810, has a disk that is tidally distorted into a rose-like shape by the gravitational tidal pull of the companion galaxy below it, known as UGC 1813. A swath of blue jewels across the top is the combined light from clusters of intensely bright and hot young blue stars. These massive stars glow fiercely in ultraviolet light. The smaller, nearly edge-on companion shows distinct signs of intense star formation at its nucleus, perhaps triggered by the encounter with the companion galaxy. A series of uncommon spiral patterns in the large galaxy is a tell-tale sign of interaction. The large, outer arm appears partially as a ring, a feature seen when interacting galaxies actually pass through one another. This suggests that the smaller companion actually dived deep, but off-center, through UGC 1810. The inner set of spiral arms is highly warped out of the plane with one of the arms going behind the bulge and coming back out the other side. How these two spiral patterns connect is still not precisely known. A possible mini-spiral may be visible in the spiral arms of UGC 1810 to the upper right. It is noticeable how the outermost spiral arm changes character as it passes this third galaxy, from smooth with lots of old stars (reddish in color) on one side to clumpy and extremely blue on the other. The fairly regular spacing of the blue star-forming knots fits with what is seen in the spiral arms of other galaxies and is predictable based on instabilities in the gas contained within the arm. The larger galaxy in the UGC 1810 – UGC 1813 pair has a mass that is about five times that of the smaller galaxy. In unequal pairs such as this, the relatively
This dramatic image offers a peek inside a cavern of roiling dust and gas where thousands of stars are forming. The image, taken by the Advanced Camera for Surveys (ACS) aboard NASA’s Hubble Space Telescope, represents the sharpest view ever taken of this region, called the Orion Nebula. More than 3,000 stars of various sizes appear in this image. Some of them have never been seen in visible light. These stars reside in a dramatic dust-and-gas landscape of plateaus, mountains, and valleys that are reminiscent of the Grand Canyon. The Orion Nebula is a picture book of star formation, from the massive, young stars that are shaping the nebula to the pillars of dense gas that may be the homes of budding stars. The bright central region is the home of the four heftiest stars in the nebula. The stars are called the Trapezium because they are arranged in a trapezoid pattern. Ultraviolet light unleashed by these stars is carving a cavity in the nebula and disrupting the growth of hundreds of smaller stars. Located near the Trapezium stars are stars still young enough to have disks of material encircling them. These disks are called protoplanetary disks or « proplyds » and are too small to see clearly in this image. The disks are the building blocks of solar systems. The bright glow at upper left is from M43, a small region being shaped by a massive, young star’s ultraviolet light. Astronomers call the region a miniature Orion Nebula because only one star is sculpting the landscape. The Orion Nebula has four such stars. Next to M43 are dense, dark pillars of dust and gas that point toward the Trapezium. These pillars are resisting erosion from the Trapezium’s intense ultraviolet light. The glowing region on the right reveals arcs and bubbles formed when stellar winds – streams of charged particles ejected from the Trapezium stars – collide with material. The faint red stars near the bottom are the myriad brown dwarfs that Hubble spied for the first time in the nebula in visib
This portrait of Stephan’s Quintet, also known as Hickson Compact Group 92, was taken by NASA’s Hubble Wide Field Camera 3 (WFC3). Stephan’s Quintet, as the name implies, is a group of five galaxies. However, studies have shown that group member NGC 7320, at upper left, is actually a foreground galaxy about 40 million light-years from Earth. The other members of the quintet reside 290 million light-years away. Three of the galaxies have distorted shapes, elongated spiral arms, and long, gaseous tidal tails containing myriad star clusters, proof of their close encounters. These interactions have sparked a frenzy of star birth in the central pair of galaxies. This drama is being played out against a rich backdrop of faraway galaxies. The galaxy group Stephan’s Quintet is located in the constellation Pegasus.
One of the largest Hubble Space Telescope images ever made of a complete galaxy is being unveiled today at the American Astronomical Society meeting in San Diego, Calif. The Hubble telescope captured a display of starlight, glowing gas, and silhouetted dark clouds of interstellar dust in this 4-foot-by-8-foot image of the barred spiral galaxy NGC 1300. NGC 1300 is considered to be prototypical of barred spiral galaxies. Barred spirals differ from normal spiral galaxies in that the arms of the galaxy do not spiral all the way into the center, but are connected to the two ends of a straight bar of stars containing the nucleus at its center. At Hubble’s resolution, a myriad of fine details, some of which have never before been seen, is seen throughout the galaxy’s arms, disk, bulge, and nucleus. Blue and red supergiant stars, star clusters, and star-forming regions are well resolved across the spiral arms, and dust lanes trace out fine structures in the disk and bar. Numerous more distant galaxies are visible in the background, and are seen even through the densest regions of NGC 1300. In the core of the larger spiral structure of NGC 1300, the nucleus shows its own extraordinary and distinct « grand-design » spiral structure that is about 3,300 light-years (1 kiloparsec) long. Only galaxies with large-scale bars appear to have these grand-design inner disks – a spiral within a spiral. Models suggest that the gas in a bar can be funneled inwards, and then spiral into the center through the grand-design disk, where it can potentially fuel a central black hole. NGC 1300 is not known to have an active nucleus, however, indicating either that there is no black hole, or that it is not accreting matter. The image was constructed from exposures taken in September 2004 by the Advanced Camera for Surveys onboard Hubble in four filters. Starlight and dust are seen in blue, visible, and infrared light. Bright star clusters are highlighted in red by their associated emission from gl
On February 24, 2009, the Hubble Space Telescope took a photo of four moons of Saturn passing in front of their parent planet. In this view, the giant orange moon Titan casts a large shadow onto Saturn’s north polar hood. Below Titan, near the ring plane and to the left is the moon Mimas, casting a much smaller shadow onto Saturn’s equatorial cloud tops. Farther to the left, and off Saturn’s disk, are the bright moon Dione and the fainter moon Enceladus. These rare moon transits only happen when the tilt of Saturn’s ring plane is nearly « edge on » as seen from the Earth. Saturn’s rings will be perfectly edge on to our line of sight on August 10, 2009, and September 4, 2009. Unfortunately, Saturn will be too close to the sun to be seen by viewers on Earth at that time. This « ring plane crossing » occurs every 14-15 years. In 1995-96 Hubble witnessed the ring plane crossing event, as well as many moon transits, and even helped discover several new moons of Saturn. The banded structure in Saturn’s atmosphere is similar to Jupiter’s. Early 2009 was a favorable time for viewers with small telescopes to watch moon and shadow transits crossing the face of Saturn. Titan, Saturn’s largest moon, crossed Saturn on four separate occasions: January 24, February 9, February 24, and March 12, although not all events were visible from all locations on Earth. These pictures were taken with Hubble’s Wide Field Planetary Camera 2 on February 24, 2009, when Saturn was at a distance of roughly 775 million miles (1.25 billion kilometers) from Earth. Hubble can see details as small as 190 miles (300 km) across on Saturn. The dark band running across the face of the planet slightly above the rings is the shadow of the rings cast on the planet.
Looking like an apparition rising from whitecaps of interstellar foam, the iconic Horsehead Nebula has graced astronomy books ever since its discovery over a century ago. The nebula is a favorite target for amateur and professional astronomers. In this new Hubble Space Telescope view, the nebula appears in a new light, as seen in infrared wavelengths. The nebula, shadowy in optical light, appears transparent and ethereal when seen in the infrared, represented here with visible shades. The rich tapestry of the Horsehead Nebula pops out against the backdrop of Milky Way stars and distant galaxies that are easily seen in infrared light. The Horsehead was photographed in celebration of the 23rd anniversary of the launch of Hubble aboard the space shuttle Discovery. Over its two decades of producing ground-breaking science, Hubble has benefited from a slew of upgrades, including the 2009 addition of a new imaging workhorse: the high-resolution Wide Field Camera 3 that was used to take this portrait of the Horsehead. The backlit wisps along the Horsehead’s upper ridge are being illuminated by Sigma Orionis, a young five-star system just off the top of the Hubble image. A harsh ultraviolet glare from one of these bright stars is slowly evaporating the nebula. Along the nebula’s top ridge, two fledgling stars peek out from their now-exposed nurseries. Gas clouds surrounding the Horsehead have already dissipated, but the tip of the jutting pillar contains a slightly higher density of hydrogen and helium, laced with dust. This casts a shadow that protects material behind it from being photo-evaporated, and a pillar structure forms. Astronomers estimate that the Horsehead formation has about five million years left before it too disintegrates. The Horsehead Nebula is part of a much larger complex in the constellation Orion. Known collectively as the Orion Molecular Cloud, it also houses other famous objects such as the Great Orion Nebula (M42), the Fla
NASA’s Hubble Space Telescope snapped this panoramic view of a colorful assortment of 100,000 stars residing in the crowded core of a giant star cluster. The image reveals a small region inside the massive globular cluster Omega Centauri, which boasts nearly 10 million stars. Globular clusters, ancient swarms of stars united by gravity, are the homesteaders of our Milky Way galaxy. The stars in Omega Centauri are between 10 billion and 12 billion years old. The cluster lies about 16,000 light-years from Earth. Omega Centauri is among the biggest and most massive of some 200 globular clusters orbiting the Milky Way. It is one of the few globular clusters that can be seen with the unaided eye. Located n the constellation Centaurus, it resembles a small cloud in the southern sky and might easily be mistaken for a comet.