A galaxy about 23 million light-years away is the site of impressive, ongoing, fireworks. Rather than paper, powder, and fire, this galactic light show involves a giant black hole, shock waves, and vast reservoirs of gas. This galactic fireworks display is taking place in NGC 4258 (also known as M106), a spiral galaxy like the Milky Way. This galaxy is famous, however, for something that our galaxy doesn't have -- two extra spiral arms that glow in X-ray, optical, and radio light. These features, or anomalous arms, are not aligned with the plane of the galaxy, but instead intersect with it. The anomalous arms are seen in this new composite image of NGC 4258, where X-rays from NASA's Chandra X-ray Observatory are blue, radio data from the NSF's Karl Jansky Very Large Array are purple, optical data from NASA's Hubble Space Telescope are yellow and blue, and infrared data from NASA's Spitzer Space Telescope are red. A new study of these anomalous arms made with Spitzer shows that shock waves, similar to sonic booms from supersonic planes, are heating large amounts of gas -- equivalent to about 10 million suns. What is generating these shock waves? Radio data shows that the supermassive black hole at the center of NGC 4258 is producing powerful jets of high-energy particles. Researchers think that these jets strike the disk of the galaxy and generate shock waves. These shock waves, in turn, heat some of the gas -- composed mainly of hydrogen molecules -- to thousands of degrees. As shown in our additional, composite image, part of the evidence for this heating process comes from the similarity in location between the hydrogen and X-ray emission, both thought to be caused by shocks, and the radio jets. The Chandra X-ray image reveals huge bubbles of hot gas above and below the plane of the galaxy. These bubbles indicate that much of the gas that was originally in the disk of the galaxy has been heated to millions of degrees and ejected into the outer regions by the jets from the black hole. The ejection of gas from the disk by the jets has important implications for the fate of this galaxy. Researchers estimate that all of the remaining gas will be ejected within the next 300 million years -- very soon on cosmic time scales -- unless it is somehow replenished. Because most of the gas in the disk has already been ejected, less gas is available for new stars to form. Indeed, the researchers used Spitzer data to estimate that stars are forming in the central regions of NGC 4258, at a rate which is about ten times less than in the Milky Way galaxy. The European Space Agency's Herschel Space Observatory, for which NASA plays an important role, was used to confirm the estimate from Spitzer data of the low star-formation rate in the central regions of NGC 4258. Herschel was also used to make an independent estimate of how much gas remains in the center of the galaxy. After allowing for the large boost in infrared emission caused by the shocks, the researchers found that the gas mass is ten times smaller than had been previously estimated. Because NGC 4258 is relatively close to Earth, astronomers can study how this black hole is affecting its galaxy in great detail. The supermassive black hole at the center of NGC 4258 is about ten times larger than the one in the Milky Way, and is also consuming material at a faster rate, potentially increasing its impact on the evolution of its host galaxy. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

Observations from NASA's Spitzer Space Telescope reveal new information about the structure of 2011 MD, a small asteroid being considered by NASA for its proposed Asteroid Redirect Mission, or ARM. Spitzer's infrared images helped reveal that this asteroid consists of about two-thirds empty space. There are several possible structures for such an asteroid, two of which are illustrated here: a loosely clumped group of boulders (left) and a solid clump loosely packed with fine debris (right).

This image of asteroid 2011 MD was taken by NASA's Spitzer Space Telescope in Feb. 2014, over a period of 20 hours. The long observation, taken in infrared light, was needed to pick up the faint signature of the small asteroid (center of frame). The Spitzer observations helped narrow down the size of the space rock to roughly 20 feet (6 meters), making it one of a few candidates for NASA's proposed Asteroid Redirect Mission for which sizes are approximately known. This image was taken by Spitzer's Infrared Array Camera at a wavelength of 4.5 microns.

Asteroids can differ in the degree of porosity, or the amount of empty space that makes up their structures. At one end of the spectrum is a single solid rock and, at the other end, is a pile of rubble held together by gravity. Observations from NASA's Spitzer Space Telescope, taken in infrared light, have helped to reveal that a small asteroid called 2011 MD is made-up of two-thirds empty space, which means it has essentially the same density as water.

Observations of infrared light coming from asteroids provide a better estimate of their true sizes than visible-light measurements. This diagram illustrates why. At left, are three asteroids with different sizes and compositions. Even though they are different, they can appear to the same to a visible-light telescope because they reflect the same amount of sunlight. It's impossible to know their sizes. For example, the small, white asteroid has a more reflective surface so it can appear to have the same brightness as a larger, dark asteroid. The same is true of a shiny penny and larger piece of dull copper -- they could, in some circumstances, reflect the same amount of total light. The right side of the illustration shows what happens in the infrared. When an asteroid is hit with sunlight, it radiates some of that back as infrared light. The amount of infrared light that comes off an asteroid thus depends on the size of its exposed surface area. When infrared and visible-light observations are combined, the reflectivity of a surface, or its albedo, can also be determined.

Observations from NASA's Spitzer Space Telescope reveal new information about the structure of 2011 MD, a small asteroid being considered by NASA for its proposed Asteroid Redirect Mission, or ARM. Spitzer's infrared images helped reveal that this asteroid consists of about two-thirds empty space. One possible structure for such an asteroid is illustrated here: a loosely clumped group of boulders.

Observations from NASA's Spitzer Space Telescope reveal new information about the structure of 2011 MD, a small asteroid being considered by NASA for its proposed Asteroid Redirect Mission, or ARM. Spitzer's infrared images helped reveal that this asteroid consists of about two-thirds empty space. One possible structure for such an asteroid is illustrated here: a solid clump loosely packed with fine debris.

NASA's Spitzer Space Telescope has teamed up with the Hubble Space Telescope to conduct the Spitzer UltRaFaint Survey, or SURFS UP. The joint project is catching sight of a "wave" of galaxies that emerged in the early universe. Starlight from these primordial galaxies is reckoned to have cleared a fog of hydrogen gas that shrouded the cosmos during a mysterious period known as the Dark Ages. SURFS UP will image 10 massive, foreground galaxy clusters, whose strong gravity magnifies the light of background objects. This so-called cosmic lensing causes objects such as the distant, dim, young galaxies that SURFS UP is investigating, to appear more than 10 times brighter than they normally would, allowing the team to study the stars within them. This image exhibits the magnifying effects of two of the galaxy clusters, the Bullet Cluster and MACS 1149. The zoom-in circles show ultra-distant galaxies that SURFS UP has revealed. The overall reddish hue of starlight visible to Spitzer in these distant galaxy indicates that the stars in these young galaxies are already mature. The findings therefore push back the time when the first stars and galaxies arose and began illuminating the Dark Ages. The Spitzer observations, in infrared, reveal key characteristics, such as mass and ages, about older populations of stars in the far-off galaxies. Besides finding the galaxies in the first place, Hubble's observations, in visible light, speak to the formation rate of young stars. Taken together, the data paint a richly detailed portrait of galactic evolution and its effect on the wider cosmos. These Spitzer observations at wavelengths of 3.5 and 4.6 microns are shown in blue and red, respectively. They were obtained during Spitzer's warm mission phase, following the depletion of its liquid coolant in 2009.

This image shows two clusters of galaxies colliding with one another, the smaller one being known as the Bullet Cluster. NASA's Spitzer Space Telescope obtained these observations during the telescope's warm mission phase, following the depletion of its liquid coolant in 2009. Spitzer, along with the Hubble Space Telescope, targeted the Bullet Cluster as part of the Spitzer UltRaFaint Survey, or SURFS UP. The joint project will image 10 massive, foreground galaxy clusters whose strong gravity magnifies the light of background objects. This so-called cosmic lensing causes objects such as the distant, dim, young galaxies that SURFS UP is investigating, to appear more than 10 times brighter than they normally would, allowing the team to study the stars within them. At least one distant, young galaxy has been detected far behind the bullet cluster but magnified by its gravitational lens effect. The overall reddish hue of starlight visible to Spitzer in this distant, young galaxy indicates that the stars in it are already mature. The findings therefore push back the time when the first stars and galaxies arose and began ending a cosmic period known as the Dark Ages. These Spitzer observations at wavelengths of 3.5 and 4.6 microns are shown in blue and red, respectively.

NASA's Spitzer Space Telescope captured this image of the galaxy cluster MACS 1149. The observations took place during the telescope's warm mission phase, following the depletion of its liquid coolant in 2009. Spitzer, along with the Hubble Space Telescope, targeted MACS 1149 as part of the Spitzer UltRaFaint Survey, or SURFS UP. The joint project will image 10 massive, foreground galaxy clusters whose strong gravity magnifies the light of background objects. This so-called cosmic lensing causes objects such as the distant, dim, young galaxies that SURFS UP is investigating, to appear more than 10 times brighter than they normally would, allowing the team to study the stars within them. At least one distant, young galaxy has been detected far behind the MACS 1149 but magnified by its gravitational lens effect. The overall reddish hue of starlight visible to Spitzer in this distant, young galaxy indicates that the stars in it are already mature. The findings therefore push back the time when the first stars and galaxies arose and began ending a cosmic period known as the Dark Ages. These Spitzer observations at wavelengths of 3.5 and 4.6 microns are shown in blue and red, respectively.

This infrared image from NASA's Spitzer Space Telescope shows a close-up of N103B -- all that remains from a supernova that exploded a millennium ago in the Large Magellanic Cloud, a satellite galaxy of the Milky Way 160,000 light years away. Spitzer's instruments pick up infrared light emitted by dust in both the remnant and the surrounding interstellar medium. The infrared light has been translated to colors we see in this image, allowing astronomers to dissect the scene. In this image, dust associated with the remnant appears red, while dust in the ambient background of the galaxy appears yellow and green. Stars in the field appear blue. By studying the infrared light emitted from this supernova remnant, astronomers have determined that the density of the gas surrounding the supernova is much higher than is typical for a 'Type Ia' supernova, which are those that occur when dead stars called white dwarfs explode. Astronomers believe that this dense material was expelled prior to the supernova explosion, possibly by a companion to the white dwarf -- an aging star that shed the material. Most Type Ia supernovas do not show evidence for this process occurring, making N103B an example of a rare subclass of Type Ia explosions. In fact, only one other remnant of a Type Ia explosion shows evidence for this: the remnant of Kepler's supernova in our own galaxy, the remains of the explosion of a star witnessed on Earth in 1604 A.D. The red data shows infrared light with wavelengths of 16 and 24 microns, while shorter-wavelength infrared light of 3.6, 4.5, and 8 microns is shown as blue, cyan and green, respectively.

This infrared image from NASA's Spitzer Space Telescope shows N103B -- all that remains from a supernova that exploded a millennium ago in the Large Magellanic Cloud, a satellite galaxy 160,000 light-years away from our own Milky Way. Spitzer's instruments pick up infrared light emitted by dust in both the remnant and the surrounding interstellar medium. The infrared light has been translated to colors we see in this image, allowing astronomers to dissect the scene. In this image, dust associated with the remnant appears red, while dust in the ambient background of the galaxy appears yellow and green. Stars in the field appear blue. By studying the infrared light emitted from this supernova remnant, astronomers have determined that the density of the gas surrounding the supernova is much higher than is typical for a 'Type Ia' supernova, which are those that occur when dead stars called white dwarfs explode. Astronomers believe that this dense material was expelled prior to the supernova explosion, possibly by a companion to the white dwarf -- an aging star that shed the material. Most Type Ia supernovas do not show evidence for this process occurring, making N103B an example of a rare subclass of Type Ia explosions. In fact, only one other remnant of a Type Ia explosion shows evidence for this: the remnant of Kepler's supernova in our own galaxy, the remains of the explosion of a star witnessed on Earth in 1604 A.D. The clump of blue stars seen at the lower right is the cluster known as NGC 1850. Also a resident of the Large Magellanic Cloud, this cluster is made up of young stars yet has the appearance of globular clusters in the Milky Way, which are much older. The red data shows infrared light with wavelengths of 16 and 24 microns, while shorter-wavelength infrared light of 3.6, 4.5, and 8 microns is shown as blue, cyan and green, respectively.

Within the swaddling dust of the Serpens Cloud Core, astronomers are studying one of the youngest collections of stars ever seen in our galaxy. This infrared image combines data from NASAs Spitzer Space Telescope with shorter-wavelength observations from the Two Micron All Sky Survey (2MASS), letting us peer into the clouds of dust wrapped around this stellar nursery. At a distance of around 750 light-years, these young stars reside within the confines of the constellation Serpens, or the Serpent. This collection contains stars of only relatively low to moderate mass, lacking any of the massive and incredibly bright stars found in larger star-forming regions like the Orion nebula. Our sun is a star of moderate mass. Whether it formed in a low-mass stellar region like Serpens, or a high-mass stellar region like Orion, is an ongoing mystery. The stellar hatchlings in the Serpens Cloud Core represent the very youngest stages of stellar development. They appear as red, orange and yellow points clustered near the center of the image. Other red features include jets of material ejected from these young stars. Some mature stars that are not in the nebula appear yellowish due to dust obscuring our view at shorter, bluer wavelengths. This region also includes a population of prenatal stars that are so deeply enshrouded in their dusty cocoons to be completely hidden in this view. They only become detectable at much longer wavelengths of light. The inner Serpens Cloud Core is remarkably detailed in this image, as it was assembled from 82 separate snapshots totaling a whopping 16.2 hours of Spitzer observing time. Serpens is one of several star-forming regions targeted by the Young Stellar Object Variability (YSOVAR) project, which conducted repeated observations in each area to look for changes in brightness in the baby stars. Such fluctuations can provide valuable clues to how stars gobble up gas and dust as they grow and mature. Spitzer observations at wavelengths of 3.5 and 4.6 microns are shown in green and red, respectively. 2MASS data at 1.3 microns is displayed as blue. These observations date from Spitzers warm mission phase, following the depletion of its liquid coolant in 2009. The 2MASS mission was a joint effort between the California Institute of Technology, Pasadena, Calif., the University of Massachusetts and NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Within the swaddling dust of the Serpens Cloud Core, astronomers are studying one of the youngest collections of stars ever seen in our galaxy. This infrared image uses data from the warm phase of NASAs Spitzer Space Telescope, letting us peer into the clouds of dust wrapped around this stellar nursery. At a distance of around 750 light-years, these young stars reside within the confines of the constellation Serpens, or the Serpent. This collection contains stars of only relatively low to moderate mass, lacking any of the massive and incredibly bright stars found in larger star-forming regions like the Orion nebula. Our sun is a star of moderate mass. Whether it formed in a low-mass stellar region like Serpens, or a high-mass stellar region like Orion, is an ongoing mystery. The stellar hatchlings in the Serpens Cloud Core represent the very youngest stages of stellar development. They appear as red, orange and yellow points clustered near the center of the image. Other red features include jets of material ejected from these young stars. Some mature stars that are not in the nebula appear yellowish due to dust obscuring our view at shorter, bluer wavelengths. This region also includes a population of prenatal stars that are so deeply enshrouded in their dusty cocoons to be completely hidden in this view. They only become detectable at much longer wavelengths of light. The inner Serpens Cloud Core is remarkably detailed in this image, as it was assembled from 82 separate snapshots totaling a whopping 16.2 hours of Spitzer observing time. Serpens is one of several star-forming regions targeted by the Young Stellar Object Variability (YSOVAR) project, which conducted repeated observations in each area to look for changes in brightness in the baby stars. Such fluctuations can provide valuable clues to how stars gobble up gas and dust as they grow and mature. Spitzer observations at wavelengths of 3.5 and 4.6 microns are shown in blue and orange, respectively. These observations date from Spitzers warm mission phase, following the depletion of its liquid coolant in 2009.

Astronomers have found cosmic clumps so dark, dense and dusty that they throw the deepest shadows ever recorded. The clumps, shown here in a zoom-in detail, were discovered within a huge cosmic cloud of gas and dust. Infrared observations from NASA's Spitzer Space Telescope of these blackest-of-black regions in the cloud paradoxically light the way to understanding how the brightest stars form. A new study takes advantage of the shadows cast by these dark clumps to measure the cloud's overall structure and mass. These dense, clumpy pockets of star-forming material within the cloud are so thick with dust that they scatter and block not only visible light, but almost all background infrared light as well. The dusty cloud, the results suggest, will likely evolve into one of the most massive young clusters of stars in our galaxy. The densest clumps will blossom into the cluster's biggest, most powerful stars, called O-type stars, the formation of which has long puzzled scientists. These hulking stars have major impacts on their local stellar environments while also helping to create the heavy elements needed for life. This image reveals the overall darkness of the cloud, calculated using Spitzer's infrared observations at a wavelength of 8 microns. Artifacts left by individual stars have been removed from the data, though several large, particularly bright areas have left white artifacts in the cloud map.

Astronomers have found cosmic clumps so dark, dense and dusty that they throw the deepest shadows ever recorded. The clumps were discovered within a huge cosmic cloud of gas and dust. Infrared observations from NASA's Spitzer Space Telescope of these blackest-of-black regions in the cloud paradoxically light the way to understanding how the brightest stars form. The large cloud looms in the center of this image of the galactic plane from Spitzer. The zoom oval to the right shows details of the cloud, revealing the dense clumps. A new study takes advantage of the shadows cast by these dark clumps to measure the cloud's overall structure and mass. These dense, clumpy pockets of star-forming material within the cloud are so thick with dust that they scatter and block not only visible light, but almost all background infrared light as well. The dusty cloud, the results suggest, will likely evolve into one of the most massive young clusters of stars in our galaxy. The densest clumps will blossom into the cluster's biggest, most powerful stars, called O-type stars, the formation of which has long puzzled scientists. These hulking stars have major impacts on their local stellar environments while also helping to create the heavy elements needed for life. The blue callout image reveals the overall darkness of the cloud, calculated using Spitzer's infrared observations at a wavelength of 8 microns. Artifacts left by individual stars have been removed from the data. The background image combines data from the Spitzer GLIMPSE and MIPSGAL surveys. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer. The red spot in the center of the zoom oval, unrelated to the new study's findings, is a young star whose radiating heat has lit up a surrounding cocoon of dust.

Astronomers have found cosmic clumps so dark, dense and dusty that they throw the deepest shadows ever recorded. The clumps were discovered within a huge cosmic cloud of gas and dust. Infrared observations from NASA's Spitzer Space Telescope of these blackest-of-black regions in the cloud paradoxically light the way to understanding how the brightest stars form. The large cloud looms in the very center of this image of the galactic plane from Spitzer. A new study takes advantage of the shadows cast by the cloud's darkest clumps to measure the cloud's overall structure and mass. The dusty cloud, the results suggest, will likely evolve into one of the most massive young clusters of stars in our galaxy. The densest clumps will blossom into the cluster's biggest, most powerful stars, called O-type stars, the formation of which has long puzzled scientists. These hulking stars have major impacts on their local stellar environments while also helping to create the heavy elements needed for life. The background image combines data from the Spitzer GLIMPSE and MIPSGAL surveys. Blue represents 3.6-micron light and green shows light of 8 microns, both captured by Spitzer's infrared array camera. Red is 24-micron light detected by Spitzer's multiband imaging photometer.

When searching for the nicest nebulas in the sky it's nice when your friends help you out. This striking star formation region, mapped in infrared light by NASA's Spitzer Space Telescope, was recently spotted by one of Spitzer's Twitter followers searching through the GLIMPSE360 panorama of our Milky Way galaxy. One of multitudes of star-forming nebulas scattered across the sky, this area had been a bit of a "dirty" secret, tucked away behind a veil of dust that blocks our view in visible light. That obscuring veil fades away under Spitzer's infrared gaze revealing a collection of young stars bursting out of the dusty gas clouds in which they formed. Astronomers identify this area only by a collection of catalog numbers like IRAS 15541-5349. This image is a tiny snippet of the vast 20 gigapixel GLIMPSE360 panorama released in March 2014. Visitors were encouraged to use the web viewers on the Spitzer site to search through the data and then share and name their findings on Twitter. This region was tweeted by @kevinmgill, who tagged it "Nebula Does Not Approve." Nebula images are a bit like a Rorschach inkblot test and the Spitzer team, on seeing the image, found plenty of other hidden parallels, including a fish, a raccoon, a Minecraft Creeper and a "cute coyote's head." This last idea lent an informal name for this hidden region: the "Coyote Head Nebula." This picture was taken with Spitzer's InfraRed Array Camera, as part of the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) project. It is a four-color composite, in which light with a wavelength of 3.6 microns is blue; 4.5-micron light is green; 5.8-micron light is orange; and 8-micron light is red. Dust is red, hot gas is green, and white is where gas and dust intermingle. Foreground and background stars appear scattered through the image.

NASA's Spitzer Space Telescope has taken on a new role for asteroid-hunting astronomers. A new software tool lets astronomers quickly comb through existing datasets to recover detections of newly-discovered asteroids from its 10+ year archive of observations. This "precovery" process extrapolates the path of a known asteroid back in time and checks to see whether at some point it may have serendipitously appeared in any of Spitzer's previous observations. Making dense archives such as Spitzer's easily accessible should add to the wealth of small Solar System body information obtained by asteroid-hunting missions like NEOWISE. For instance, observations of objects at varying locations in their orbits, where sunlight glints off them at distinct angles like the phases of the Moon, can reveal characteristics about their shapes and textures. Additionally, seeing an object at different points in time also lends a hand in calculating its trajectory through space.

Stars are often born in clusters or groups, in giant clouds of gas and dust. Astronomers have studied two star clusters using NASAs Chandra X-ray Observatory and infrared telescopes and the results show that the simplest ideas for the birth of these clusters cannot work. This composite image shows one of the clusters, NGC 2024, which is found in the center of the so-called Flame Nebula about 1,4000 light years from Earth. In this image, X-rays from Chandra are seen as purple, while infrared data from NASAs Spitzer Space Telescope are colored red, green, and blue. A study of NGC 2024 and the Orion Nebula Cluster, another region where many stars are forming, suggest that the stars on the outskirts of these clusters are older than those in the central regions. This is different from what the simplest idea of star formation predicts, where stars are born first in the center of a collapsing cloud of gas and dust when the density is large enough. The research team developed a two-step process to make this discovery. First, they used Chandra data on the brightness of the stars in X-rays to determine their masses. Next, they found out how bright these stars were in infrared light using data from Spitzer, the 2MASS telescope, and the United Kingdom Infrared Telescope. By combining this information with theoretical models, the ages of the stars throughout the two clusters could be estimated. According to the new results, the stars at the center of NGC 2024 were about 200,000 years old while those on the outskirts were about 1.5 million years in age. In Orion, the age spread went from 1.2 million years in the middle of the cluster to nearly 2 million years for the stars toward the edges. Explanations for the new findings can be grouped into three broad categories. The first is that star formation is continuing to occur in the inner regions. This could have happened because the gas in the outer regions of a star-forming cloud is thinner and more diffuse than in the inner regions. Over time, if the density falls below a threshold value where it can no longer collapse to form stars, star formation will cease in the outer regions, whereas stars will continue to form in the inner regions, leading to a concentration of younger stars there. Another suggestion is that old stars have had more time to drift away from the center of the cluster, or be kicked outward by interactions with other stars. Finally, the observations could be explained if young stars are formed in massive filaments of gas that fall toward the center of the cluster. These results will be published in two separate papers in The Astrophysical Journal and are available online (papers 1 and 2). They are part of the MYStIX (Massive Young Star-Forming Complex Study in Infrared and X-ray) project led by Penn State astronomers.

This 4-panel image shows the coldest brown dwarf yet seen, and the fourth closest system to our sun. Called WISE J085510.83-071442.5, this dim object was discovered through its rapid motion across the sky. It was first seen in two infrared images taken six months apart in 2010 by NASA's Wide-field Infrared Survey Explorer, or WISE (see yellow triangles). Two additional images of the object were taken with NASA's Spitzer Space Telescope in 2013 and 2014 (green triangles). All four images were used to measure the distance to the object -- 7.2 light-years -- using the parallax effect. The Spitzer data were used to show that the body is as cold as the North Pole (or between minus 54 and 9 degrees Fahrenheit, which is minus 48 to minus 13 degrees Celsius).

This artist's conception shows the object named WISE J085510.83-071442.5, the coldest known brown dwarf. Brown dwarfs are dim star-like bodies that lack the mass to burn nuclear fuel as stars do. WISE J085510.83-071442.5 is as cold as the North Pole (or between minus 54 and 9 degrees Fahrenheit, which is minus 48 to minus 13 degrees Celsius). The color of the brown dwarf in this image is arbitrary; it would have different colors when viewed in different wavelength ranges. This celestial orb is also the fourth closest to our sun, at 7.2 light-years from Earth. In this illustration, the sun is the bright star directly to the right of the brown dwarf. Our sun's closest neighboring system (not pictured) is Alpha Centauri, at 4 light-years from Earth. The slightly shifted star field accurately reflects how the sky around the constellations of Aquila and Delphinus would appear from the vantage point of WISE J085510.83-071442.5 and was rendered using Microsoft's WorldWide Telescope.

This diagram illustrates the locations of the star systems closest to the sun. The year when the distance to each system was determined is listed after the system's name. NASA's Wide-field Infrared Survey Explorer, or WISE, found two of the four closest systems: the binary brown dwarf WISE 1049-5319 and the brown dwarf WISE J085510.83-071442.5. NASA's Spitzer Space Telescope helped pin down the location of the latter object. The closest system to the sun is a trio of stars that consists of Alpha Centauri, a close companion to it and the more distant companion Proxima Centauri.

This quartet of galaxies comes from a collaboration of professional and amateur astronomers that combines optical data from amateur telescopes with data from the archives of NASA missions. Starting in the upper left and moving clockwise, the galaxies are M101 (the "Pinwheel Galaxy"), M81, Centaurus A, and M51 (the "Whirlpool Galaxy"). In these images, X-rays from Chandra are in pink, infrared data from Spitzer are red, and the optical data are in red, green, and blue. The two astrophotographers who donated their images for these composites -- Detlef Hartmann and Rolf Olsen -- used their personal telescopes of 17.5 inches and 10 inches in diameter respectively.

J0717 isn't just a large cluster of galaxies; astronomers are using it like a giant telephoto lens attachment to study the very distant, very faint universe. This new infrared view from NASA's Spitzer Space Telescope will be used in tandem with observations from other major NASA observatories to glimpse the universe's very first galaxies. Called Frontier Fields, the project is a collaboration with the Hubble Space Telescope and the Chandra X-ray Observatory. The faintness of the earliest, most distant galaxies makes studying them a challenge, even with long, deep exposures. Frontier Fields, however, can spot these primordial galaxies courtesy of foreground clusters of galaxies, whose gargantuan mass and gravity form cosmic "zoom lenses." The clusters warp space around them, magnifying background galaxies. The cluster in this image, known as J0717, is the grouping of bright objects near the center of the field, while examples of the very distant background galaxies appear as distorted arcs at the center of the two circular call-outs.

The clusters warp space around them, magnifying background galaxies. The cluster in this image, known as J0717, is the grouping of bright objects near the center of the field. Upon close examination, examples of the very distant background galaxies can be seen as distorted arcs scattered through the cluster. The effect is somewhat like looking through the bottom of a wine glass, which both magnifies and alters the shape of background objects. On average, the gravitational warping of space by foreground clusters magnifies background galaxies four to ten times. But some galaxies studied via Frontier Fields will be magnified on the order of a hundred times. Spitzer's sensitive infrared observations will be used to gauge the mass of the foreground clusters and background galaxies. The observatory will also help determine if certain galaxies are in fact the far-off, early galaxies of interest or just nearby galaxies. Observations from Spitzer's Infrared Array Camera (IRAC) at 3.6 and 4.5 microns have been combined into a single blue-tinted image. This data was collected during Spitzer's "warm" mission phase, which began in May 2009 after the telescope exhausted the last of its liquid coolant.

Each of these panels shows 60 degrees of Spitzer's new 360-degree infrared view of our Milky Way Galaxy. The full 360-degree mosaic comes primarily from the GLIMPSE360 project, which stands for Galactic Legacy Mid-Plane Survey Extraordinaire. It consists of more than 2 million snapshots taken in infrared light over ten years, beginning in 2003 when Spitzer launched. This infrared view reveals much more of the galaxy than can be seen in visible-light views. Whereas visible light is blocked by dust, infrared light from stars and other objects can travel through dust to reach Spitzer's detectors. For instance, when looking up at our night skies, we see stars that are an average of 1,000 light-years away; the rest are hidden. In Spitzer's mosaic, light from stars throughout the galaxy -- which stretches 100,000 light-years across -- shines through. The full 360-degree picture covers only about three percent of the sky, but includes more than half of the galaxy's stars and the majority of its star formation activity. Blue stars seen in these images are relatively close to us, while the red color shows dusty areas of star formation. Throughout the galaxy, tendrils, bubbles and sculpted dust structures are apparent. These are the result of massive stars blasting out winds and radiation. Stellar clusters deeply embedded in gas and dust, green jets and other features related to the formation of young stars can also be seen for the first time. Dark filaments that show up in stark contrast to the bright background are areas of thick, cold dust that not even infrared light can penetrate. For the full resolution view of this image, see http://www.spitzer.caltech.edu/glimpse360/downloads. (Warning: these files are very large - approximately 600mb - 1gb each)

Each of these panels shows 60 degrees of Spitzer's new 360-degree infrared view of our Milky Way Galaxy. The full 360-degree mosaic comes primarily from the GLIMPSE360 project, which stands for Galactic Legacy Mid-Plane Survey Extraordinaire. It consists of more than 2 million snapshots taken in infrared light over ten years, beginning in 2003 when Spitzer launched. This infrared view reveals much more of the galaxy than can be seen in visible-light views. Whereas visible light is blocked by dust, infrared light from stars and other objects can travel through dust to reach Spitzer's detectors. For instance, when looking up at our night skies, we see stars that are an average of 1,000 light-years away; the rest are hidden. In Spitzer's mosaic, light from stars throughout the galaxy -- which stretches 100,000 light-years across -- shines through. The full 360-degree picture covers only about three percent of the sky, but includes more than half of the galaxy's stars and the majority of its star formation activity. Blue stars seen in these images are relatively close to us, while the red color shows dusty areas of star formation. Throughout the galaxy, tendrils, bubbles and sculpted dust structures are apparent. These are the result of massive stars blasting out winds and radiation. Stellar clusters deeply embedded in gas and dust, green jets and other features related to the formation of young stars can also be seen for the first time. Dark filaments that show up in stark contrast to the bright background are areas of thick, cold dust that not even infrared light can penetrate. For the full resolution view of this image, see http://www.spitzer.caltech.edu/glimpse360/downloads. (Warning: these files are very large - approximately 600mb - 1gb each)

Each of these panels shows 60 degrees of Spitzer's new 360-degree infrared view of our Milky Way Galaxy. The full 360-degree mosaic comes primarily from the GLIMPSE360 project, which stands for Galactic Legacy Mid-Plane Survey Extraordinaire. It consists of more than 2 million snapshots taken in infrared light over ten years, beginning in 2003 when Spitzer launched. This infrared view reveals much more of the galaxy than can be seen in visible-light views. Whereas visible light is blocked by dust, infrared light from stars and other objects can travel through dust to reach Spitzer's detectors. For instance, when looking up at our night skies, we see stars that are an average of 1,000 light-years away; the rest are hidden. In Spitzer's mosaic, light from stars throughout the galaxy -- which stretches 100,000 light-years across -- shines through. The full 360-degree picture covers only about three percent of the sky, but includes more than half of the galaxy's stars and the majority of its star formation activity. Blue stars seen in these images are relatively close to us, while the red color shows dusty areas of star formation. Throughout the galaxy, tendrils, bubbles and sculpted dust structures are apparent. These are the result of massive stars blasting out winds and radiation. Stellar clusters deeply embedded in gas and dust, green jets and other features related to the formation of young stars can also be seen for the first time. Dark filaments that show up in stark contrast to the bright background are areas of thick, cold dust that not even infrared light can penetrate. For the full resolution view of this image, see http://www.spitzer.caltech.edu/glimpse360/downloads. (Warning: these files are very large - approximately 600mb - 1gb each)

Each of these panels shows 60 degrees of Spitzer's new 360-degree infrared view of our Milky Way Galaxy. The full 360-degree mosaic comes primarily from the GLIMPSE360 project, which stands for Galactic Legacy Mid-Plane Survey Extraordinaire. It consists of more than 2 million snapshots taken in infrared light over ten years, beginning in 2003 when Spitzer launched. This infrared view reveals much more of the galaxy than can be seen in visible-light views. Whereas visible light is blocked by dust, infrared light from stars and other objects can travel through dust to reach Spitzer's detectors. For instance, when looking up at our night skies, we see stars that are an average of 1,000 light-years away; the rest are hidden. In Spitzer's mosaic, light from stars throughout the galaxy -- which stretches 100,000 light-years across -- shines through. The full 360-degree picture covers only about three percent of the sky, but includes more than half of the galaxy's stars and the majority of its star formation activity. Blue stars seen in these images are relatively close to us, while the red color shows dusty areas of star formation. Throughout the galaxy, tendrils, bubbles and sculpted dust structures are apparent. These are the result of massive stars blasting out winds and radiation. Stellar clusters deeply embedded in gas and dust, green jets and other features related to the formation of young stars can also be seen for the first time. Dark filaments that show up in stark contrast to the bright background are areas of thick, cold dust that not even infrared light can penetrate. For the full resolution view of this image, see http://www.spitzer.caltech.edu/glimpse360/downloads. (Warning: these files are very large - approximately 600mb - 1gb each)