NASA's Spitzer Space Telescope has captured these infrared images of a nearby spiral galaxy that resembles our own Milky Way. The targeted galaxy, known as NGC 7331 and sometimes referred to as our galaxy's twin, is found in the constellation Pegasus at a distance of 50 million light-years. This inclined galaxy was discovered in 1784 by William Herschel, who also discovered infrared light. The evolution of this galaxy is a story that depends significantly on the amount and distribution of gas and dust, the locations and rates of star formation, and on how the energy from star formation is recycled by the local environment. The new Spitzer images are allowing astronomers to "read" this story by dissecting the galaxy into its separate components. The main image, measuring 12.6 by 8.2 arcminutes, was obtained by Spitzer's infrared array camera. It is a four-color composite of invisible light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (yellow) and 8.0 microns (red). These wavelengths are roughly 10 times longer than those seen by the human eye. The infrared light seen in this image originates from two very different sources. At shorter wavelengths (3.6 to 4.5 microns), the light comes mainly from stars, particularly ones that are older and cooler than our Sun. This starlight fades at longer wavelengths (5.8 to 8.0 microns), where instead we see the glow from clouds of interstellar dust. This dust consists mainly of a variety of carbon-based organic molecules known collectively as polycyclic aromatic hydrocarbons. Wherever these compounds are found, there will also be dust granules and gas, which provide a reservoir of raw materials for future star formation. These shorter- and longer-wavelength views are shown separately as insets. Perhaps the most intriguing feature of the longer-wavelength image is a ring of dust girdling the galaxy center. This ring, with a radius of nearly 20,000 light-years, is invisible at shorter wavelengths, yet has been detected at sub-millimeter and radio wavelengths. It is made up in large part of polycyclic aromatic hydrocarbons. Spitzer measurements suggest that the ring contains enough gas to produce four billion stars like the Sun. Starlight was systematically subtracted from the longer-wavelength picture to enhance dust features. Three other galaxies are seen below NGC 7331, all about 10 times farther away. From left to right are NGC 7336, NGC 7335 and NGC 7337. The blue dots scattered throughout the images are foreground stars in the Milky Way; the red ones are galaxies that are even more distant. The Spitzer observations of NGC 7311 are part of a large 500-hour science project, known as the Spitzer Infrared Nearby Galaxy Survey, which will comprehensively study 75 nearby galaxies with infrared imaging and spectroscopy.

NGC 7331 was discovered by William Herschel in 1784. It is one of the brightest galaxies which is not included in Messier's catalog. It shows a fine spiral structure despite its small inclination from the edge-on position. Several companions and background galaxies are also visible in this image.

This image provides a close-up look at two of the extremely bright infrared galaxies revealed by NASA's Spitzer Space Telescope. While they are very faint (bottom) or even completely invisible (top) in the deepest-ever optical images obtained by NASA's Hubble Space Telescope, Spitzer easily picked them up because of their strong infrared emissions. Astronomers believe these galaxies are particularly "red" because they are very old and appear to go back in time to a period when the universe was only two billion years old.

This image taken by NASA's Spitzer Space Telescope shows in unprecedented detail the galaxy Centaurus A's last big meal: a spiral galaxy seemingly twisted into a parallelogram-shaped structure of dust. Spitzer's ability to see dust and also see through it allowed the telescope to peer into the center of Centaurus A and capture this galactic remnant as never before. An elliptical galaxy located 10 million light-years from Earth, Centaurus A is one of the brightest sources of radio waves in the sky. These radio waves indicate the presence of a supermassive black hole, which may be "feeding" off the leftover galactic meal. A high-speed jet of gas can be seen shooting above the plane of the galaxy (the faint, fuzzy feature pointing from the center toward the upper left). Jets are a common feature of galaxies, and this one is probably receiving an extra boost from the galactic remnant. Scientists have created a model that explains how such a strangely geometric structure could arise. In this model, a spiral galaxy falls into an elliptical galaxy, becoming warped and twisted in the process. The folds in the warped disc create the parallelogram-shaped illusion.

Astronomers have probed the deep sky with NASA's three Great Observatories for hidden black holes and come to the conclusion that most black holes cannot be seen in visible images. The image on the left from NASA's Hubble Space Telescope shows 1/200 of the full field of sky known as the Great Observatories Origins Deep Survey, or GOODS. It highlights three X-ray sources (circled) and many other galaxies. The image on the right is made up of data from Hubble and NASA's Spitzer Space Telescope and shows the same region. The two "hard" X-ray sources (sources detected only at the shortest X-ray wavelengths and indicated here with yellow circles) are very faint in the visible but much more luminous in the infrared. This data suggests that the X-ray sources are black holes hidden behind a screen of dust.

This image taken by NASA's Spitzer Space Telescope shows in unprecedented detail the galaxy Centaurus A's last big meal: a spiral galaxy seemingly twisted into a parallelogram-shaped structure of dust. Spitzer's ability to see dust and also see through it allowed the telescope to peer into the center of Centaurus A and capture this galactic remnant as never before. An elliptical galaxy located 10 million light-years from Earth, Centaurus A is one of the brightest sources of radio waves in the sky. These radio waves indicate the presence of a supermassive black hole, which may be "feeding" off the leftover galactic meal. A high-speed jet of gas can be seen shooting above the plane of the galaxy (the faint, fuzzy feature pointing from the center toward the upper left). Jets are a common feature of galaxies, and this one is probably receiving an extra boost from the galactic remnant. Scientists have created a model that explains how such a strangely geometric structure could arise. In this model, a spiral galaxy falls into an elliptical galaxy, becoming warped and twisted in the process. The folds in the warped disc create the parallelogram-shaped illusion.

This image taken by NASA's Spitzer Space Telescope shows in unprecedented detail the galaxy Centaurus A's last big meal: a spiral galaxy seemingly twisted into a parallelogram-shaped structure of dust. An elliptical galaxy located 10 million light-years from Earth, Centaurus A is one of the brightest sources of radio waves in the sky. These radio waves indicate the presence of a supermassive black hole, which may be "feeding" off the leftover galactic meal. This spectacular image combines 5.8 micron and 8.0 micron data obtained by an infrared array camera aboard Spitzer. These wavelengths emphasize the emission from dust rather than the light produced by stars in the galaxy. The resulting image shows with greater clarity the strange parallelogram-shaped feature embedded near the center of the galaxy. Scientists have created a model that explains how such a strangely geometric structure could arise. In this model, a spiral galaxy falls into an elliptical galaxy, becoming warped and twisted in the process. The folds in the warped disc create the parallelogram-shaped illusion.

In a collaborative effort between NASA's three Great Observatories, astronomers have solved a cosmic mystery by identifying some of the oldest and most distant black holes. The two rows of this image show two patches of sky, both contained within the field known as the Great Observatories Origins Deep Survey, or GOODS. In the first column, observations from the Chandra X-ray Observatory show high-energy emissions believed to trace the presence of supermassive black holes, which power the bright cores of distant galaxies. The mystery emerges in the second column. While most of the black hole candidates observed by Chandra could easily be identified within host galaxies seen by NASA's Hubble Space Telescope, several of them, like the two pictured here, showed no sign of a galaxy in visible light. The images in the third column, from NASA's Spitzer Space Telescope, show the same region in infrared light. In these images, the otherwise invisible galaxies reappear. These unusually "reddened" objects may be shrouded in dense clouds of obscuring dust, or may be remarkably distant compared to other galaxies in the same field. Additional Spitzer observations later this year should help astronomers determine the nature of these unusual objects.

This image shows the relative locations of the RCW 49 and Taurus star-forming regions. The top panel shows an artist's concept of our own Milky Way Galaxy as seen from above, with the relative locations of the Sun, the nearby Taurus region, and the more distant RCW 49 nebula. In the bottom panel, these regions are marked in the sky as seen from Earth in nearly opposite directions. The top half shows the stars of the Milky Way, and the bottom half shows the far infrared view of the dust clouds in the Milky Way.

One of the most prolific birthing grounds in our Milky Way galaxy, a nebula called RCW 49, is exposed in superb detail for the first time in this new image from NASA's Spitzer Space Telescope. Located 13,700 light-years away in the southern constellation Centaurus, RCW 49 is a dark and dusty stellar nursery that houses more than 2,200 stars. Because many of the stars in RCW 49 are deeply embedded in plumes of dust, they cannot be seen at visible wavelengths. When viewed with Spitzer's infrared eyes, however, RCW 49 becomes transparent. Like cracking open a quartz rock to discover its jewels inside, the nebula's newborn stars have been dramatically exposed. This image taken by Spitzer's infrared array camera highlights the nebula's older stars (blue stars in center pocket), its gas filaments (green) and dusty tendrils (pink). Speckled throughout the murky clouds are more than 300 never-before-seen newborn stars. Astronomers are interested in further studying these newfound proto-stars because they offer a fresh look at star formation in our own galaxy. This image was taken on Dec. 23, 2003, and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

In this artist's conception, a possible newfound planet spins through a clearing in a nearby star's dusty, planet-forming disc. This clearing was detected around the star CoKu Tau 4 by NASA's Spitzer Space Telescope. Astronomers believe that an orbiting massive body, like a planet, may have swept away the star's disc material, leaving a central hole.The possible planet is theorized to be at least as massive as Jupiter, and may have a similar appearance to what the giant planets in our own solar system looked like billions of years ago. A graceful ring, much like Saturn's, spins high above the planet's cloudy atmosphere. The ring is formed from countless small orbiting particles of dust and ice, leftovers from the initial gravitational collapse that formed the possible giant planet.If we were to visit a planet like this, we would have a very different view of the universe. The sky, instead of being the familiar dark expanse lit by distant stars, would be dominated by the thick disc of dust that fills this young planetary system. The view looking toward CoKu Tau 4 would be relatively clear, as the dust in the interior of the disc has fallen into the accreting star. A bright band would seem to surround the central star, caused by light scattered back by the dust in the disc. Looking away from CoKu Tau 4, the dusty disc would appear dark, blotting out light from all the stars in the sky except those which lie well above the plane of the disc.

Using sensitive instruments onboard NASA's Spitzer Space Telescope, scientists have seen the first building blocks of planets, and possibly future life, deep within dusty discs around young stars. The image shows spectra, obtained by Spitzer's infrared spectrograph, of two stars that are so young they are still embedded in protoplanetary discs. These thick discs of gas and dust are the leftover material from the formation of the stars themselves. The spectra are graphical representations of a celestial object's unique blend of light. Characteristic patterns, or fingerprints, within the spectra allow astronomers to identify the object's chemical composition. In both infrared spectra, the presence of important chemicals for the formation of new worlds can be seen clearly. The broad depression in the center of each spectrum signifies the presence of silicates, which are chemically similar to beach sand. In fact, a good match for the chemistry of these crystalline silicates may be the famous green beaches of Hawaii, which get their color from olivine crystals in the sand. The depth of the silicate absorption feature indicates that the dusty cocoon surrounding the embedded protostar is extremely thick. Other absorption dips are produced by water ice (blue), methanol ice (red), and carbon dioxide ice (green). The fact that water, methanol and carbon dioxide appear in solid form suggests that the material immediately surrounding the protostar is cold.

One of the most prolific birthing grounds in our Milky Way galaxy, a nebula called RCW 49, is exposed in superb detail for the first time in this new image from NASA's Spitzer Space Telescope. Located 13,700 light-years away in the southern constellation Centaurus, RCW 49 is a dark and dusty stellar nursery that houses more than 2,200 stars. Because many of the stars in RCW 49 are deeply embedded in plumes of dust, they cannot be seen at visible wavelengths. When viewed with Spitzer's infrared eyes, however, RCW 49 becomes transparent. Like cracking open a quartz rock to discover its jewels inside, the nebula's newborn stars have been dramatically exposed. This image taken by Spitzer's infrared array camera highlights the nebula's older stars (blue stars in center pocket), its gas filaments (green) and dusty tendrils (pink). Speckled throughout the murky clouds are more than 300 never-before-seen newborn stars. Astronomers are interested in further studying these newfound proto-stars because they offer a fresh look at star formation in our own galaxy. This image was taken on Dec. 23, 2003, and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

How can you tell if a star has a protoplanetary disk around it, when the disk is too small to image directly? Using the technique of spectroscopy, scientists can deduce the temperature and chemical composition of material around a star, even if they cannot see the disk itself. Spectroscopy involves spreading the light from a star into a spectrum (in visible light, we are familiar with white light being spread out into a rainbow when it passes through a prism), and then measuring exactly how much light is present in each wavelength. The top illustration represents the spectrum of a star with no circumstellar disk or other surrounding material. The distribution of light at any given wavelength follows a specific and well-known line, determined by the laws of physics and the temperature of the star. In the case of a star, most of the light is produced at shorter wavelengths (the left side of the diagram), due to the high temperature of the star's surface. Moving to the right-hand side of the diagram, the wavelengths increase to lower energies (indicating lower temperatures) and, the starlight drops off. In the second diagram, we see the spectrum of a star with a disk of dust and gas around it. The warm dust and gas disk around the star produces its own infrared light, which changes the shape of the spectrum. The circumstellar material is cooler than the surface of the star, so it emits most of its light at longer infrared wavelengths, closer to the right-hand side of the diagram. Now, there is an excess of infrared emission, which can not be coming from the star itself. The disk is revealed. Going a step further, in the third diagram we see the spectrum of a star with a circumstellar disk around it, but in this case, the inner part of the disk has been swept away, perhaps by the formation of a planet. The dust closest to the star was also the hottest, so its absence means that there is less emission from the disk at higher temperatures. The only dust producing infrared light is much cooler than the star, and radiates only at long wavelengths. This low temperature "bump" on the spectrum indicates a disk with a missing center, and may be the first clue that planets have formed inside the disk.

Using sensitive instruments onboard NASA's Spitzer Space Telescope, scientists have seen the first building blocks of planets, and possibly future life, deep within dusty discs around young stars. The image shows spectra, obtained by Spitzer's infrared spectrograph, of two stars that are so young they are still embedded in protoplanetary discs. These thick discs of gas and dust are the leftover material from the formation of the stars themselves. The spectra are graphical representations of a celestial object's unique blend of light. Characteristic patterns, or fingerprints, within the spectra allow astronomers to identify the object's chemical composition. In both infrared spectra, the presence of important chemicals for the formation of new worlds can be seen clearly. The broad depression in the center of each spectrum signifies the presence of silicates, which are chemically similar to beach sand. In fact, a good match for the chemistry of these crystalline silicates may be the famous green beaches of Hawaii, which get their color from olivine crystals in the sand. The artist's conception in the background depicts a close-up view of tiny olivine crystals, which scientists believe make up at least some of the dust grains, becoming coated with ice deep within the disc. The depth of the silicate absorption feature indicates that the dusty cocoon surrounding the embedded protostar is extremely thick. Other absorption dips are produced by water ice (blue), methanol ice (red), and carbon dioxide ice (green). The fact that water, methanol and carbon dioxide appear in solid form suggests that the material immediately surrounding the protostar is cold.

In the quest to better understand the birth of stars and the formation of new worlds, astronomers have used NASA's Spitzer Space Telescope to examine the massive stars contained in a cloudy region called Sharpless 140. This cloud is a fascinating microcosm of a star-forming region since it exhibits, within a relatively small area, all of the classic manifestations of stellar birth. Sharpless 140 lies almost 3000 light-years from Earth in the constellation Cepheus. At its heart is a cluster of three deeply embedded young stars, which are each several thousand times brighter than the Sun. Though they are strikingly visible in this image from Spitzer's infrared array camera, they are completely obscured in visible light, buried within the core of the surrounding dust cloud. The extreme youth of at least one of these stars is indicated by the presence of a stream of gas moving at high velocities. Such outflows are signatures of the processes surrounding a star that is still gobbling up material as part of its formation. The bright red bowl, or arc, seen in this image traces the outer surface of the dense dust cloud encasing the young stars. This arc is made up primarily of organic compounds called polycyclic aromatic hydrocarbons, which glow on the surface of the cloud. Ultraviolet light from a nearby bright star outside of the image is "eating away" at these molecules. Eventually, this light will destroy the dust envelope and the masked young stars will emerge. This image was taken on Oct. 11, 2003 and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

Sometimes, the best way to understand how something works is to take it apart. The same is true for galaxies like NGC 300, which NASA's Spitzer Space Telescope has divided into its various parts. NGC 300 is a face-on spiral galaxy located 7.5 million light-years away in the southern constellation Sculptor. This image taken by the infrared array camera on Spitzer readily distinguishes the main star component of the galaxy (blue) from its dusty spiral arms (red). The star distribution peaks strongly in the central bulge where older stars congregate, and tapers off along the arms where younger stars reside. Thanks to Spitzer's unique ability to sense the heat or infrared emission from dust, astronomers can now clearly trace the embedded dust structures within NGC 300's arms. When viewed at visible wavelengths, the galaxy's dust appears as dark lanes, largely overwhelmed by bright starlight. With Spitzer, the dust -- in particular organic compounds called polycyclic aromatic hydrocarbons -- can be seen in vivid detail (red). These organic molecules are produced, along with heavy elements, by the stellar nurseries that pepper the arms. The findings provide a better understanding of spiral galaxy mechanics and, in the future, will help decipher more distant galaxies, whose individual components cannot be resolved. This image was taken on Nov. 21, 2003 and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

In the quest to better understand the birth of stars and the formation of new worlds, astronomers have used NASA's Spitzer Space Telescope to examine the massive stars contained in a cloudy region called Sharpless 140. This cloud is a fascinating microcosm of a star-forming region since it exhibits, within a relatively small area, all of the classic manifestations of stellar birth. Sharpless 140 lies almost 3000 light-years from Earth in the constellation Cepheus. At its heart is a cluster of three deeply embedded young stars, which are each several thousand times brighter than the Sun. Though they are strikingly visible in this image from Spitzer's infrared array camera, they are completely obscured in visible light, buried within the core of the surrounding dust cloud. The extreme youth of at least one of these stars is indicated by the presence of a stream of gas moving at high velocities. Such outflows are signatures of the processes surrounding a star that is still gobbling up material as part of its formation. The bright red bowl, or arc, seen in this image traces the outer surface of the dense dust cloud encasing the young stars. This arc is made up primarily of organic compounds called polycyclic aromatic hydrocarbons, which glow on the surface of the cloud. Ultraviolet light from a nearby bright star outside of the image is "eating away" at these molecules. Eventually, this light will destroy the dust envelope and the masked young stars will emerge. This image was taken on Oct. 11, 2003 and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

Sometimes, the best way to understand how something works is to take it apart. The same is true for galaxies like NGC 300, which NASA's Spitzer Space Telescope has divided into its various parts. NGC 300 is a face-on spiral galaxy located 7.5 million light-years away in the southern constellation Sculptor. This image taken by the infrared array camera on Spitzer readily distinguishes the main star component of the galaxy (blue) from its dusty spiral arms (red). The star distribution peaks strongly in the central bulge where older stars congregate, and tapers off along the arms where younger stars reside. Thanks to Spitzer's unique ability to sense the heat or infrared emission from dust, astronomers can now clearly trace the embedded dust structures within NGC 300's arms. When viewed at visible wavelengths, the galaxy's dust appears as dark lanes, largely overwhelmed by bright starlight. With Spitzer, the dust -- in particular organic compounds called polycyclic aromatic hydrocarbons -- can be seen in vivid detail (red). These organic molecules are produced, along with heavy elements, by the stellar nurseries that pepper the arms. The findings provide a better understanding of spiral galaxy mechanics and, in the future, will help decipher more distant galaxies, whose individual components cannot be resolved. This image was taken on Nov. 21, 2003 and is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red).

This near-infrared image, from the Two-Micron All-Sky Survey (2MASS), of the DR21 region covers an area about two times that of a full moon. Many stars are discerned in this image because near-infrared light pierces through some of the obscuration of the interstellar dust.

Hidden behind a shroud of dust in the constellation Cygnus is an exceptionally bright source of radio emission called DR21. Visible light images reveal no trace of what is happening in this region because of heavy dust obscuration. In fact, visible light is attenuated in DR21 by a factor of more than 10,000,000,000,000,000,000,000,000,000, 000,000,000,000 (ten thousand trillion heptillion). This image from NASA's Spitzer Space Telescope allow us to peek behind the cosmic veil and pinpoint one of the most massive natal stars yet seen in our Milky Way galaxy. The never-before-seen star is 100,000 times as bright as the Sun. Also revealed for the first time is a powerful outflow of hot gas emanating from this star and bursting through a giant molecular cloud. This image is a large-scale mosaic assembled from individual photographs obtained with the InfraRed Array Camera (IRAC) aboard Spitzer. The image covers an area about two times that of a full moon. The mosaic is a composite of images obtained at mid-infrared wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The brightest infrared cloud near the top center corresponds to DR21, which presumably contains a cluster of newly forming stars at a distance of 10,000 light-years. Protruding out from DR21 toward the bottom left of the image is a gaseous outflow (green), containing both carbon monoxide and molecular hydrogen. Data from the Spitzer spectrograph, which breaks light into its constituent individual wavelengths, indicate the presence of hot steam formed as the outflow heats the surrounding molecular gas. Outflows are physical signatures of processes that create supersonic beams, or jets, of gas. They are usually accompanied by discs of material around the new star, which likely contain the materials from which future planetary systems are formed. Additional newborn stars, depicted in green, can be seen surrounding the DR21 region. The red filaments stretching across this image denote the presence of polycyclic aromatic hydrocarbons. These organic molecules, comprised of carbon and hydrogen, are excited by surrounding interstellar radiation and become luminescent at wavelengths near 8.0 microns. The complex pattern of filaments is caused by an intricate combination of radiation pressure, gravity and magnetic fields. The result is a tapestry in which winds, outflows and turbulence move and shape the interstellar medium. To the lower left of the mosaic is a large bubble of gas and dust, which may represent the remnants of a past generation of stars.

Hidden behind a shroud of dust in the constellation Cygnus is a stellar nursery called DR21, which is giving birth to some of the most massive stars in our galaxy. Visible light images reveal no trace of this interstellar cauldron because of heavy dust obscuration. In fact, visible light is attenuated in DR21 by a factor of more than 10,000,000,000, 000,000,000,000,000,000,000,000,000,000 (ten thousand trillion heptillion). NASA's Spitzer Space Telescope allows us to peek behind the cosmic veil and pinpoint one of the most massive natal stars yet seen in our Milky Way galaxy. The never-before-seen star is 100,000 times as bright as the Sun. Also revealed for the first time is a powerful outflow of hot gas emanating from this star and bursting through a giant molecular cloud. This colorful image is a large-scale composite mosaic assembled from data collected at a variety of different wavelengths. Views at visible wavelengths appear blue, near-infrared light is depicted as green, and mid-infrared data from the InfraRed Array Camera (IRAC) aboard NASA's Spitzer Space Telescope is portrayed as red. The result is a contrast between structures seen in visible light (blue) and those observed in the infrared (yellow and red). A quick glance shows that most of the action in this image is revealed to the unique eyes of Spitzer. The image covers an area about two times that of a full moon.

This Digital Sky Survey (DSS) image provides a familiar view of the DR21 region, with stars scattered around a dark field. The reddish hue is from gas heated by foreground stars in this region.

Hidden behind a shroud of dust in the constellation Cygnus is an exceptionally bright source of radio emission called DR21. Visible light images reveal no trace of what is happening in this region because of heavy dust obscuration. In fact, visible light is attenuated in DR21 by a factor of more than 10,000,000,000,000,000,000,000,000,000, 000,000,000,000 (ten thousand trillion heptillion). This image, from NASA's Spitzer Space Telescope, allows us to peek behind the cosmic veil and pinpoint one of the most massive natal stars yet seen in our Milky Way galaxy. The never-before-seen star is 100,000 times as bright as the Sun. Also revealed for the first time is a powerful outflow of hot gas emanating from this star and bursting through a giant molecular cloud. The image shows a 24-micron image mosaic, obtained with the Multiband Imaging Photometer aboard Spitzer (MIPS). This image maps the cooler infrared emission from interstellar dust found throughout the interstellar medium. The DR21 complex is clearly seen near the center of the strip, which covers about twice the area of the IRAC image. Perhaps the most fascinating feature in this image is a long and shadowy linear filament extending towards the 10 o'clock position of DR21. This jet of cold and dense gas, nearly 50 light-years in extent, appears in silhouette against a warmer background. This filament is too long and massive to be a stellar jet and may have formed from a pre-existing molecular cloud core sculpted by DR21's strong winds. Regardless of its true nature, this jet and the numerous other arcs and wisps of cool dust signify the interstellar turbulence normally unseen by the human eye.

Hidden behind a shroud of dust in the constellation Cygnus is an exceptionally bright source of radio emission called DR21. Visible light images reveal no trace of what is happening in this region because of heavy dust obscuration. In fact, visible light is attenuated in DR21 by a factor of more than 10,000,000,000,000,000,000,000,000,000, 000,000,000,000 (ten thousand trillion heptillion). New images from NASA's Spitzer Space Telescope allow us to peek behind the cosmic veil and pinpoint one of the most massive natal stars yet seen in our Milky Way galaxy. The never-before-seen star is 100,000 times as bright as the Sun. Also revealed for the first time is a powerful outflow of hot gas emanating from this star and bursting through a giant molecular cloud. The upper image is a large-scale mosaic assembled from individual photographs obtained with the InfraRed Array Camera (IRAC) aboard Spitzer. The image covers an area about two times that of a full moon. The mosaic is a composite of images obtained at mid-infrared wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The brightest infrared cloud near the top center corresponds to DR21, which presumably contains a cluster of newly forming stars at a distance of 10,000 light-years. Protruding out from DR21 toward the bottom left of the image is a gaseous outflow (green), containing both carbon monoxide and molecular hydrogen. Data from the Spitzer spectrograph, which breaks light into its constituent individual wavelengths, indicate the presence of hot steam formed as the outflow heats the surrounding molecular gas. Outflows are physical signatures of processes that create supersonic beams, or jets, of gas. They are usually accompanied by discs of material around the new star, which likely contain the materials from which future planetary systems are formed. Additional newborn stars, depicted in green, can be seen surrounding the DR21 region. The red filaments stretching across this image denote the presence of polycyclic aromatic hydrocarbons. These organic molecules, comprised of carbon and hydrogen, are excited by surrounding interstellar radiation and become luminescent at wavelengths near 8.0 microns. The complex pattern of filaments is caused by an intricate combination of radiation pressure, gravity and magnetic fields. The result is a tapestry in which winds, outflows and turbulence move and shape the interstellar medium. To the lower left of the mosaic is a large bubble of gas and dust, which may represent the remnants of a past generation of stars. The lower panel shows a 24-micron image mosaic, obtained with the Multiband Imaging Photometer aboard Spitzer (MIPS). This image maps the cooler infrared emission from interstellar dust found throughout the interstellar medium. The DR21 complex is clearly seen near the center of the strip, which covers about twice the area of the IRAC image. Perhaps the most fascinating feature in this image is a long and shadowy linear filament extending towards the 10 o'clock position of DR21. This jet of cold and dense gas, nearly 50 light-years in extent, appears in silhouette against a warmer background. This filament is too long and massive to be a stellar jet and may have formed from a pre-existing molecular cloud core sculpted by DR21's strong winds. Regardless of its true nature, this jet and the numerous other arcs and wisps of cool dust signify the interstellar turbulence normally unseen by the human eye.

Hidden behind a shroud of dust in the constellation Cygnus is a stellar nursery called DR21, which is giving birth to some of the most massive stars in our galaxy. Visible light images reveal no trace of this interstellar cauldron because of heavy dust obscuration. In fact, visible light is attenuated in DR21 by a factor of more than 10,000,000,000, 000,000,000,000,000,000,000,000,000,000 (ten thousand trillion heptillion). New images from NASA's Spitzer Space Telescope allow us to peek behind the cosmic veil and pinpoint one of the most massive natal stars yet seen in our Milky Way galaxy. The never-before-seen star is 100,000 times as bright as the Sun. Also revealed for the first time is a powerful outflow of hot gas emanating from this star and bursting through a giant molecular cloud. The colorful image (top panel) is a large-scale composite mosaic assembled from data collected at a variety of different wavelengths. Views at visible wavelengths appear blue, near-infrared light is depicted as green, and mid-infrared data from the InfraRed Array Camera (IRAC) aboard NASA's Spitzer Space Telescope is portrayed as red. The result is a contrast between structures seen in visible light (blue) and those observed in the infrared (yellow and red). A quick glance shows that most of the action in this image is revealed to the unique eyes of Spitzer. The image covers an area about two times that of a full moon. Each of the constituent images is shown below the large mosaic. The Digital Sky Survey (DSS) image (lower left) provides a familiar view of deep space, with stars scattered around a dark field. The reddish hue is from gas heated by foreground stars in this region. This fluorescence fades away in the near-infrared Two-Micron All-Sky Survey (2MASS) image (lower center), but other features start to appear through the obscuring clouds of dust, now increasingly transparent. Many more stars are discerned in this image because near-infrared light pierces through some of the obscuration of the interstellar dust. Note that some stars seen as very bright in the visible image are muted in the near-infrared image, whereas other stars become more prominent. Embedded nebulae revealed in the Spitzer image are only hinted at in this picture. The Spitzer image (lower right) provides a vivid contrast to the other component images, revealing star-forming complexes and large-scale structures otherwise hidden from view. The Spitzer image is composed of photographs obtained at four wavelengths: 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange) and 8 microns (red). The brightest infrared cloud near the top center corresponds to DR21, which presumably contains a cluster of newly forming stars at a distance of nearly 10,000 light-years. The red filaments stretching across the Spitzer image denote the presence of polycyclic aromatic hydrocarbons. These organic molecules, comprised of carbon and hydrogen, are excited by surrounding interstellar radiation and become luminescent at wavelengths near 8 microns. The complex pattern of filaments is caused by an intricate combination of radiation pressure, gravity, and magnetic fields. The result is a tapestry in which winds, outflows, and turbulence move and shape the interstellar medium.

Visible-light images of the Trifid taken with NASA's Hubble Space Telescope, Baltimore, Md. (inset) and the National Optical Astronomy Observatory, Tucson, Ariz., (background image) show a murky cloud lined with dark trails of dust. Data of this same region from the Institute for Radioastronomy millimeter telescope in Spain revealed four dense knots, or cores, of dust, which are "incubators" for embryonic stars. Astronomers thought these cores were not yet ripe for stars, until Spitzer spotted the warmth of rapidly growing massive embryos tucked inside.

This image composite compares visible-light views with an infrared view from NASA's Spitzer Space Telescope of the glowing Trifid Nebula, a giant star-forming cloud of gas and dust located 5,400 light-years away in the constellation Sagittarius. Visible-light images of the Trifid taken with NASA's Hubble Space Telescope, Baltimore, Md. (inside left) and the National Optical Astronomy Observatory, Tucson, Ariz., (outside left) show a murky cloud lined with dark trails of dust. Data of this same region from the Institute for Radioastronomy millimeter telescope in Spain revealed four dense knots, or cores, of dust (outlined by yellow circles), which are "incubators" for embryonic stars. Astronomers thought these cores were not yet ripe for stars, until Spitzer spotted the warmth of rapidly growing massive embryos tucked inside. These embryos are indicated with arrows in the false-color Spitzer picture (right), taken by the telescope's infrared array camera. The same embryos cannot be seen in the visible-light pictures (left). Spitzer found clusters of embryos in two of the cores and only single embryos in the other two. This is one of the first times that multiple embryos have been observed in individual cores at this early stage of stellar development.

The artist's rendition shows the newly discovered planet-like object, dubbed "Sedna," in relation to other bodies in the Solar System, including Earth and its Moon; Pluto; and Quaoar, a planetoid beyond Pluto that was until now the largest known object beyond Pluto. The diameter of Sedna is slightly smaller than Pluto's but likely somewhat larger than Quaoar.

This view shows where the newly discovered planet-like body, dubbed "Sedna," would lie in the evening skies at around 8:00 p.m. Pacific Standard Time on the date its discovery was announced (March 15, 2004). It was located in the constellation of Cetus and formed a triangle with Mars and Venus in the direction of the setting Sun. Sedna is so faint, however, that it can not be seen with the naked eye, or with telescopes typically used by amateur astronomers.