Messier 74, also known as the Phantom Galaxy, is seen here in infrared light which showcases its sweeping spiral arms and star-forming regions. This image was created using archival data from NASA's Spitzer Space Telescope, revealing dust clouds that, in visible light, appear dark. Messier 74 is an archetype of the "grand design" spiral galaxy and is nearly face-on to our view, providing a perfect view of its structure. In this infrared image, the light from stars appears blue, as stars are brightest at shorter wavelengths of infrared light and less visible at longer wavelengths. Filamentary dust clouds are a feature of spiral arms, and help to trace regions where gas reaches higher densities and can lead to the formation of stars. These clouds light up at longer wavelengths of light, appearing as pale yellow filaments. Regions of newly-forming stars show up as bright red dots scattered along the arms, as they glow most brightly at the longest infrared wavelengths in this image. The galaxy is located in the Pisces constellation and is situated about 30 million light-years away. It has a visible diameter of approximately 10 arc minutes, which is about a third as wide as the full moon. However, its low surface brightness makes it too faint to be seen with the naked eye and makes it a challenging target even for small backyard telescopes. In this image, infrared light at wavelengths of 3.6, 4.5, and 8.0 microns from Spitzer’s IRAC instrument is displayed as blue, cyan, and green, respectively, while light from Spitzer’s MIPS instrument at 24 microns is shown in red.

Messier 74, also known as the Phantom Galaxy, is seen here in infrared light which showcases its sweeping spiral arms and star-forming regions. This image was created using archival data from NASA's Spitzer Space Telescope, revealing dust clouds that, in visible light, appear dark. Messier 74 is an archetype of the "grand design" spiral galaxy and is nearly face-on to our view, providing a perfect view of its structure. In this infrared image, the light from stars appears blue, as stars are brightest at shorter wavelengths of infrared light and less visible at longer wavelengths. The dust clouds, which light up at longer wavelengths of light, are rendered as red. Filamentary dust clouds are a feature of spiral arms, and help to trace regions where gas reaches higher densities and can lead to the formation of stars. The galaxy is located in the Pisces constellation and is situated about 30 million light-years away. It has a visible diameter of approximately 10 arc minutes, which is about a third as wide as the full moon. However, its low surface brightness makes it too faint to be seen with the naked eye and makes it a challenging target even for small backyard telescopes. In this image, infrared light at wavelengths of 3.6, 4.5, and 8.0 microns is displayed as blue, green, and red, respectively.

A contingent of young stars and star-forming gas clouds is sticking out of one of the Milky Way's spiral arms like a splinter protruding from a plank of wood. Stretching some 3,000 light-years, this is the first major structure identified with such a dramatically different orientation relative to the arm. This diagram shows the structure, as well as its size and distance from the Sun. The nearby spiral arms are also noted. The star shapes indicate a star-forming region that may contain anywhere from dozens to thousands of stars. (Among these are the Eagle Nebula, the Omega Nebula, the Trifid Nebula, and the Lagoon Nebula). These stars and star-forming regions are moving through space together, at roughly the same speed and in the same direction. A key property of spiral arms is how tightly they wind around a galaxy. This characteristic is measured by the arm's pitch angle. A circle has a pitch angle of 0 degrees; as the spiral becomes more open, the pitch angle increases. Most models of the Milky Way suggest that the Sagittarius Arm forms a spiral that has a pitch angle of about 12 degrees, but the protruding structure has a pitch angle of nearly 60 degrees. Similar structures – sometimes called spurs or feathers – are commonly found jutting out of the arms of other spiral galaxies. For decades scientists have wondered whether our Milky Way's spiral arms are also dotted with these structures or if they are relatively smooth.

A contingent of young stars and star-forming gas clouds is sticking out of one of the Milky Way's spiral arms like a splinter protruding from a plank of wood. Stretching some 3,000 light-years, this is the first major structure identified with such a dramatically different orientation relative to the arm. The background image shows the location of the splinter in the Milky Way. The yellow region in the center of the image is the galaxy's bright and crowded center. The galaxy's arms spiral around the center, and are full of stars and star-forming clouds of gas and dust. The inset (Figure 1) provides a closer view of the structure, as well as its size and distance from the Sun. The nearby spiral arms are also noted. The star shapes indicate a star-forming region that may contain anywhere from dozens to thousands of stars. (Among these are the Eagle Nebula, the Omega Nebula, the Trifid Nebula, and the Lagoon Nebula). These stars and star-forming regions are moving through space together, at roughly the same speed and in the same direction. A key property of spiral arms is how tightly they wind around a galaxy. This characteristic is measured by the arm's pitch angle. A circle has a pitch angle of 0 degrees; as the spiral becomes more open, the pitch angle increases. Most models of the Milky Way suggest that the Sagittarius Arm forms a spiral that has a pitch angle of about 12 degrees, but the protruding structure has a pitch angle of nearly 60 degrees. Similar structures – sometimes called spurs or feathers – are commonly found jutting out of the arms of other spiral galaxies. For decades scientists have wondered whether our Milky Way's spiral arms are also dotted with these structures or if they are relatively smooth.

This image shows galaxy Arp 148, captured by NASA's Spitzer and Hubble telescopes. Also known as "Mayall's Object," Arp 148 captures a point in the interaction of two galaxies in which a ring has formed in the wake of their collision. The thick clouds of dusty material in the elongated galaxy (left) glow brightly in the infrared wavelengths of light seen by Spitzer (8 microns, red), while the glow of starlight dominates the visible light data from Hubble (0.3-0.8 microns, blue-green).

This image shows galaxy Arp 148, captured by NASA's Spitzer and Hubble telescopes. Inside the white circle is specially-processed Spitzer data, which reveals infrared light from a supernova that is hidden by dust. Supernovae are massive stars that have exploded after running out of fuel. They radiate most brightly in visible light (the kind the human eye can detect), but these wavelengths are obscured by dust. Infrared light, however, can pass through dust. The analysis of Arp 148 was part of an effort to find hidden supernovae in 40 dust-choked galaxies that also emit high levels of infrared light. These galaxies are known as luminous and ultra-luminous infrared galaxies (LIRGs and ULIRGs, respectively). The dust in LIRGs and ULIRGs absorbs optical light from objects like supernovae but allows infrared light from these same objects to pass through unobstructed for telescopes like Spitzer to detect. 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, also in Pasadena. Caltech manages JPL for NASA. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The Space Telescope Science Institute conducts Hubble science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington, D.C.

Two supermassive black holes are locked in an orbital dance at the core of the distant galaxy OJ 287. This diagram shows their sizes relative to the solar system. The larger one, with about 18 billion times the mass of our sun (right), would encompass all the planets in the solar system with room to spare. The smaller one is about 150 million times the mass of our sun (left), which would be large enough to swallow up everything out to the asteroid belt, just inside the orbit of Jupiter.

This artwork shows two massive black holes in the OJ 287 galaxy. The smaller black hole orbits the larger one, which remains stationary and is surrounded by a disk of gas. When the smaller black hole crashes through the disk, it produces a flare brighter than 1 trillion stars. But the smaller black hole's orbit is elongated and moving relative to the disk, causing the flares to occur irregularly.

The nearby spiral galaxy, Messier 81 (M81) is shown in this image from NASA's Spitzer Space Telescope. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years. This image shows us M81 at infrared wavelengths of light at 3.6 & 4.5 microns (blue & green). At these shorter wavelengths of infrared light we are seeing the light from the stars in this galaxy, unobscured by dust that blocks our view in the visible spectrum. M81 appears remarkably smooth in this picture, demonstrating how well-blended the populations of stars can be even in spiral galaxies. The spiral arms so visible in other parts of the spectrum are subdued and gives us a clearer picture of how stellar mass is distributed through the galaxy.

Wispy patterns of dust trace the spiral arms of the nearby galaxy Messier 81 in this image from NASA's Spitzer Space Telescope. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years. The infrared view of M81 at a wavelength of 8 microns (red) has been specially processed in this image to remove most of the glow of starlight to isolate the glow of dust. This image reveals the distribution of dust throughout M81, from its outer spiral arms all the wan into its core. This image shows infrared light at a wavelength of 8 microns (red) that has been specially processed to remove most of the glow of starlight to better highlight the dust. Dust in the galaxy is bathed by ultraviolet and visible light from nearby stars. Upon absorbing an ultraviolet or visible-light photon, a dust grain is heated and re-emits the energy at longer infrared wavelengths. The dust particles are composed of silicates (chemically similar to beach sand), carbonaceous grains and polycyclic aromatic hydrocarbons and trace the gas distribution in the galaxy. The well-mixed gas (which is best detected at radio wavelengths) and dust provide a reservoir of raw materials for future star formation. Since stars have been subtracted from this image, there are a scattering of black dots in M81 that are an artifact of this process. Most of the other red dots outside of the galaxy represent the glow of dust within even more distant background galaxies.

The magnificent spiral arms of the nearby galaxy Messier 81 are highlighted in this image from NASA's Spitzer Space Telescope. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years. M81 was one of the first publicly-released datasets soon after Spitzers launch in August of 2003. On the occasion of Spitzers 16th anniversary this new image revisits this iconic object with extended observations and improved processing. This Spitzer infrared image is a composite mosaic combining data from the Infrared Array Camera (IRAC) at wavelengths of 3.6/4.5 microns (blue/cyan) and 8 microns (green) with data from the Multiband Imaging Photometer (MIPS) at 24 microns (red). The 3.6-micron near-infrared data (blue) traces the distribution of stars, although the Spitzer image is virtually unaffected by obscuring dust and reveals a very smooth stellar mass distribution, with the spiral arms relatively subdued. As one moves to longer wavelengths, the spiral arms become the dominant feature of the galaxy. The 8-micron emission (green) is dominated by infrared light radiated by hot dust that has been heated by nearby luminous stars. Dust in the galaxy is bathed by ultraviolet and visible light from nearby stars. Upon absorbing an ultraviolet or visible-light photon, a dust grain is heated and re-emits the energy at longer infrared wavelengths. The dust particles are composed of silicates (chemically similar to beach sand), carbonaceous grains and polycyclic aromatic hydrocarbons and trace the gas distribution in the galaxy. The well-mixed gas (which is best detected at radio wavelengths) and dust provide a reservoir of raw materials for future star formation. The 24-micron MIPS data (red) shows emission from warm dust heated by the most luminous young stars. The scattering of compact red spots along the spiral arms show where the dust is warmed to high temperatures near massive stars that are being born in giant H II (ionized hydrogen) regions.

The magnificent spiral arms of the nearby galaxy Messier 81 are highlighted in this NASA Spitzer Space Telescope image. Located in the northern constellation of Ursa Major (which also includes the Big Dipper), this galaxy is easily visible through binoculars or a small telescope. M81 is located at a distance of 12 million light-years. M81 was one of the first publicly-released datasets soon after Spitzers launch in August of 2003. On the occasion of Spitzers 16th anniversary this new image revisits this iconic object with extended observations and improved processing. Because of its proximity, M81 provides astronomers with an enticing opportunity to study the anatomy of a spiral galaxy in detail. The unprecedented spatial resolution and sensitivity of Spitzer at infrared wavelengths show a clear separation between the several key constituents of the galaxy: the old stars, the interstellar dust heated by star formation activity, and the embedded sites of massive star formation. The infrared images also permit quantitative measurements of the galaxy's overall dust content, as well as the rate at which new stars are being formed. Winding outward from the bluish-white central bulge of the galaxy, where old stars predominate and there is little dust, the grand spiral arms are dominated by infrared emission from dust. Dust in the galaxy is bathed by ultraviolet and visible light from the surrounding stars. Upon absorbing an ultraviolet or visible-light photon, a dust grain is heated and re-emits the energy at longer infrared wavelengths. The dust particles, composed of silicates (which are chemically similar to beach sand) and polycyclic aromatic hydrocarbons, trace the gas distribution in the galaxy. The well-mixed gas (which is best detected at radio wavelengths) and dust provide a reservoir of raw materials for future star formation. The infrared-bright clumpy knots within the spiral arms denote where massive stars are being born in giant H II (ionized hydrogen) regions. The 8-micron emission traces the regions of active star formation in the galaxy. Studying the locations of these regions with respect to the overall mass distribution and other constituents of the galaxy (e.g., gas) will help identify the conditions and processes needed for star formation. With the Spitzer observations, this information comes to us without complications from absorption by cold dust in the galaxy, which makes interpretation of visible-light features uncertain. The infrared image was obtained by Spitzer's Infrared Array Camera (IRAC) that combines three wavelengths of infrared light: 3.6 microns (blue), 4.5 microns (green), and 8.0 microns (red).

This image shows the Whirlpool galaxy, also known as Messier 51 and NGC 5194/5195, which is actually a pair of galaxies. Located approximately 23 million light-years away, it resides in the constellation Canes Venatici. Here we see four wavelengths of infrared light: 3.6 microns (shown in blue), 4.5 microns (cyan), 8 microns (green), and 24 microns (red) as observed by NASA's Spitzer Space Telescope. The blended light from the billions of stars in the Whirlpool is brightest at the shorter infrared wavelengths, and is seen here as a blue haze. The 24 micron observation is particularly good for highlighting areas where the dust is especially hot. The bright reddish-white spots trace regions where new stars are forming and, in the process, heating their surroundings. All of the data shown here were released as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) project, captured during Spitzers cryogenic and warm missions. The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

This image shows the Whirlpool galaxy, also known as Messier 51 and NGC 5194/5195, which is actually a pair of galaxies. Located approximately 23 million light-years away, it resides in the constellation Canes Venatici. Here we see three wavelengths of infrared light: 3.6 microns (shown in blue), 4.5 microns (green) and 8 microns (red), as observed by NASA's Spitzer Space Telescope. The blended light from the billions of stars in the Whirlpool is brightest at the shorter infrared wavelengths, and is seen here as a blue haze. The individual blue dots across the image are mostly nearby stars and a few distant galaxies. Red features (at 8 microns) show us dust composed mostly of carbon that is lit up by the stars in the galaxy. All of the data shown here were released as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) project, captured during Spitzers cryogenic and warm missions. The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

This image shows the Whirlpool galaxy, also known as Messier 51 and NGC 5194/5195, which is actually a pair of galaxies. Located approximately 23 million light-years away, it resides in the constellation Canes Venatici. This image combines two visible light wavelengths (in blue and green) and infrared light (in red). The infrared was captured by NASA's Spitzer Space Telescope, and emphasizes how the dark dust veins that block our view in visible light begin to light up at these longer, infrared wavelengths. All of the data shown here were released as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) project, captured during Spitzers cryogenic and warm missions. The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

This image shows the Whirlpool galaxy, also known as Messier 51 and NGC 5194/5195, which is actually a pair of galaxies. Located approximately 23 million light-years away, it resides in the constellation Canes Venatici. This image presents the galaxy's appearance in visible light, from the Kitt Peak National Observatory 2.1-meter (6.8-foot) telescope and shows light at 0.4 microns (blue) and 0.7 microns (green). All of the data shown here were released as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) project, captured during Spitzers cryogenic and warm missions. The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

This image from NASA's Spitzer Space Telescope shows the elliptical galaxy Messier 87 (M87), the home galaxy of the supermassive black hole recently imaged by the Event Horizon Telescope (EHT). Spitzer's infrared view shows a faint trace of a jet of material spewing to the right of the galaxy - a feature that was previously one key indicator that a supermassive black hole lived at the galaxy's center. More prominent in the image is the shockwave created by that jet. The inset in the image below shows a close-up view of the shockwave on the right side of the galaxy, as well as the shockwave from a second jet traveling to the left of the galaxy. Located about 55 million light-years from Earth, M87 has been a subject of astronomical study for more than 100 years and has been imaged by many NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory and NuSTAR. In 1918, astronomer Heber Curtis first noticed "a curious straight ray" extending from the galaxy's center. This bright jet (which appears to extend to the right of the galaxy) is visible in multiple wavelengths of light, from radio waves through X-rays. The jet is produced by a disk of material spinning rapidly around the black hole, and spewing in opposite directions away from the galaxy. When the particles in the jet impact the interstellar medium (the sparse material filling the space between stars in M87), they create a shockwave that radiates in infrared and radio wavelengths of light, but not visible light. The jet on the right is traveling almost directly toward Earth, and its brightness is amplified due to its high speed in our direction. But the jet's trajectory is just slightly offset from our line of sight with the galaxy, so we can still see some of the length of the jet. The shockwave begins around the point where the jet appears to curve down, highlighting the regions where the fast-moving particles are colliding with gas in the galaxy and slowing down. There is also a second jet on the left that is moving so rapidly away from us it is rendered invisible at all wavelengths. But the shockwave it creates in the interstellar medium can still be seen here. In the Spitzer image, the shockwave is on the left side of the galaxy and looks like an inverted letter "C." This image from NASA's Spitzer Space Telescope shows M87 looks like a hazy, blue space-puff. At the galaxy's center is a supermassive black hole that spews two jets of material out into space. This image shows a wide-field image of M87, also taken by NASA's Spitzer Space Telescope. Scientists are still striving for a solid theoretical understanding of how inflowing gas around black holes creates outflowing jets. Infrared light at wavelengths of 3.4 and 4.5 microns are rendered in blue and green, showing the distribution of stars, while dust features that glow brightly at 8.0 microns are shown in red. The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

This image from NASA's Spitzer Space Telescope shows the elliptical galaxy Messier 87 (M87), the home galaxy of the supermassive black hole recently imaged by the Event Horizon Telescope (EHT). Spitzer's infrared view shows a faint trace of a jet of material spewing to the right of the galaxy - a feature that was previously one key indicator that a supermassive black hole lived at the galaxy's center. More prominent in the image is the shockwave created by that jet. The inset in the image below shows a close-up view of the shockwave on the right side of the galaxy, as well as the shockwave from a second jet traveling to the left of the galaxy. Located about 55 million light-years from Earth, M87 has been a subject of astronomical study for more than 100 years and has been imaged by many NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory and NuSTAR. In 1918, astronomer Heber Curtis first noticed "a curious straight ray" extending from the galaxy's center. This bright jet (which appears to extend to the right of the galaxy) is visible in multiple wavelengths of light, from radio waves through X-rays. The jet is produced by a disk of material spinning rapidly around the black hole, and spewing in opposite directions away from the galaxy. When the particles in the jet impact the interstellar medium (the sparse material filling the space between stars in M87), they create a shockwave that radiates in infrared and radio wavelengths of light, but not visible light. The jet on the right is traveling almost directly toward Earth, and its brightness is amplified due to its high speed in our direction. But the jet's trajectory is just slightly offset from our line of sight with the galaxy, so we can still see some of the length of the jet. The shockwave begins around the point where the jet appears to curve down, highlighting the regions where the fast-moving particles are colliding with gas in the galaxy and slowing down. There is also a second jet on the left that is moving so rapidly away from us it is rendered invisible at all wavelengths. But the shockwave it creates in the interstellar medium can still be seen here. In the Spitzer image, the shockwave is on the left side of the galaxy and looks like an inverted letter "C." This image from NASA's Spitzer Space Telescope shows M87 looks like a hazy, blue space-puff. At the galaxy's center is a supermassive black hole that spews two jets of material out into space. This image shows a wide-field image of M87, also taken by NASA's Spitzer Space Telescope. The top inset shows a close-up of two shockwaves, created by a jet emanating from the galaxy's supermassive black hole. The Event Horizon Telescope recently took a close-up image of the silhouette of that black hole, shown in the second inset. Scientists are still striving for a solid theoretical understanding of how inflowing gas around black holes creates outflowing jets. Infrared light at wavelengths of 3.4 and 4.5 microns are rendered in blue and green, showing the distribution of stars, while dust features that glow brightly at 8.0 microns are shown in red. The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

This image from NASA's Spitzer Space Telescope shows the elliptical galaxy Messier 87 (M87), the home galaxy of the supermassive black hole recently imaged by the Event Horizon Telescope (EHT). Spitzer's infrared view shows a faint trace of a jet of material spewing to the right of the galaxy - a feature that was previously one key indicator that a supermassive black hole lived at the galaxy's center. More prominent in the image is the shockwave created by that jet. The inset in the image below shows a close-up view of the shockwave on the right side of the galaxy, as well as the shockwave from a second jet traveling to the left of the galaxy. Located about 55 million light-years from Earth, M87 has been a subject of astronomical study for more than 100 years and has been imaged by many NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory and NuSTAR. In 1918, astronomer Heber Curtis first noticed "a curious straight ray" extending from the galaxy's center. This bright jet (which appears to extend to the right of the galaxy) is visible in multiple wavelengths of light, from radio waves through X-rays. The jet is produced by a disk of material spinning rapidly around the black hole, and spewing in opposite directions away from the galaxy. When the particles in the jet impact the interstellar medium (the sparse material filling the space between stars in M87), they create a shockwave that radiates in infrared and radio wavelengths of light, but not visible light. The jet on the right is traveling almost directly toward Earth, and its brightness is amplified due to its high speed in our direction. But the jet's trajectory is just slightly offset from our line of sight with the galaxy, so we can still see some of the length of the jet. The shockwave begins around the point where the jet appears to curve down, highlighting the regions where the fast-moving particles are colliding with gas in the galaxy and slowing down. There is also a second jet on the left that is moving so rapidly away from us it is rendered invisible at all wavelengths. But the shockwave it creates in the interstellar medium can still be seen here. In the Spitzer image, the shockwave is on the left side of the galaxy and looks like an inverted letter "C." This image from NASA's Spitzer Space Telescope shows M87 looks like a hazy, blue space-puff. At the galaxy's center is a supermassive black hole that spews two jets of material out into space. This image shows a wide-field image of M87, also taken by NASA's Spitzer Space Telescope. The inset shows a close-up of two shockwaves, created by a jet emanating from the galaxy's supermassive black hole. Scientists are still striving for a solid theoretical understanding of how inflowing gas around black holes creates outflowing jets. Infrared light at wavelengths of 3.4 and 4.5 microns are rendered in blue and green, showing the distribution of stars, while dust features that glow brightly at 8.0 microns are shown in red. The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

This image shows two merging galaxies known as Arp 302, also called VV 340. In these images, different colors correspond to different wavelengths of infrared light. Blue and green are wavelengths both strongly emitted by stars. Red is a wavelength mostly emitted by dust.

This image shows the merger of two galaxies, known as NGC 6786 (right) and UGC 11415 (left), also collectively called VII Zw 96. It is composed of images from three Spitzer Infrared Array Camera (IRAC) channels: IRAC channel 1 in blue, IRAC channel 2 in green and IRAC channel 3 in red.

This image shows the merger of two galaxies, known as NGC 7752 (larger) and NGC 7753 (smaller), also collectively called Arp86. In these images, different colors correspond to different wavelengths of infrared light. Blue and green are wavelengths both strongly emitted by stars. Red is a wavelength mostly emitted by dust.

An artist's concept of a tidal disruption event (TDE) that happens when a star passes fatally close to a supermassive black hole, which reacts by launching a relativistic jet.

An image of the galaxy Arp299B, which is undergoing a merging process with Arp299A (the galaxy to the left), captured by NASA's Hubble space telescope. The inset features an artist's illustration of a tidal disruption event (TDE), which occurs when a star passes fatally close to a supermassive black hole. A TDE was recently observed near the center of Arp299B.

This image of distant interacting galaxies, known collectively as Arp 142, bears an uncanny resemblance to a penguin guarding an egg. Data from NASA's Spitzer and Hubble space telescopes have been combined to show these dramatic galaxies in light that spans the visible and infrared parts of the spectrum. This dramatic pairing shows two galaxies that couldn't look more different as their mutual gravitational attraction slowly drags them closer together. The "penguin" part of the pair, NGC 2336, was probably once a relatively normal-looking spiral galaxy, flattened like a pancake with smoothly symmetric spiral arms. Rich with newly-formed hot stars, seen in visible light from Hubble as bluish filaments, its shape has now been twisted and distorted as it responds to the gravitational tugs of its neighbor. Strands of gas mixed with dust stand out as red filaments detected at longer wavelengths of infrared light seen by Spitzer. The "egg" of the pair, NGC 2937, by contrast, is nearly featureless. The distinctly different greenish glow of starlight tells the story of a population of much older stars. The absence of glowing red dust features informs us that it has long since lost its reservoir of gas and dust from which new stars can form. While this galaxy is certainly reacting to the presence of its neighbor, its smooth distribution of stars obscures any obvious distortions of its shape. Eventually these two galaxies will merge to form a single object, with their two populations of stars, gas and dust intermingling. This kind of merger was likely a significant step in the history of most large galaxies we see around us in the nearby universe, including our own Milky Way. At a distance of about 352 million light-years, these two galaxies are roughly 10 times farther away than our nearest major galactic neighbor, the Andromeda galaxy. The blue streak at the top of the image is an unrelated background galaxy that is farther away than Arp 142. Combining light from across the visible and infrared spectrums helps astronomers piece together the complex story of the life cycles of galaxies. While this image required data from both the Spitzer and Hubble telescopes to cover this range of light, NASA's upcoming James Webb Space Telescope will be able to see all of these wavelengths of light, and with dramatically better clarity.

NASAs Spitzer Space Telescope has provisionally detected the faint afterglow of the explosive merger of two neutron stars in the galaxy NGC 4993. The event, labeled GW170817, was initially detected nearly simultaneously in gravitational waves and gamma rays, but subsequent observations by many dozens of telescopes have monitored its afterglow across the entire spectrum of light. Spitzers observation on September 29th comes late in the game, just over 6 weeks after the event was first seen, but if this weak detection is verified, it will play an important role in helping astronomers understand how many of the heaviest elements in the periodic table are created in explosive neutron star mergers. This image shows the residual 4.5 micron data from Spitzer's IRAC instrument after subtracting out the light of the galaxy using an archival image that predates the event. The faint dot framed by the markers may be one of the last detections made in infrared light of this event.

NASAs Spitzer Space Telescope has provisionally detected the faint afterglow of the explosive merger of two neutron stars in the galaxy NGC 4993. The event, labeled GW170817, was initially detected nearly simultaneously in gravitational waves and gamma rays, but subsequent observations by many dozens of telescopes have monitored its afterglow across the entire spectrum of light. Spitzers observation on September 29th comes late in the game, just over 6 weeks after the event was first seen, but if this weak detection is verified, it will play an important role in helping astronomers understand how many of the heaviest elements in the periodic table are created in explosive neutron star mergers. This image is a color composite of the 3.6 and 4.5 micron channels of the Spitzer IRAC instrument, rendered in cyan and red. The faint light from the explosion is to faint to be easily seen mixed in the light of the other stars in the galaxy.

NASAs Spitzer Space Telescope has provisionally detected the faint afterglow of the explosive merger of two neutron stars in the galaxy NGC 4993. The event, labeled GW170817, was initially detected nearly simultaneously in gravitational waves and gamma rays, but subsequent observations by many dozens of telescopes have monitored its afterglow across the entire spectrum of light. Spitzers observation on September 29th comes late in the game, just over 6 weeks after the event was first seen, but if this weak detection is verified, it will play an important role in helping astronomers understand how many of the heaviest elements in the periodic table are created in explosive neutron star mergers. The left panel is a color composite of the 3.6 and 4.5 micron channels of the Spitzer IRAC instrument, rendered in cyan and red. The center panel is a median-filtered color composite showing a faint red dot at the known location of the event. The right panel shows the residual 4.5 micron data after subtracting out the light of the galaxy using an archival image that predates the event.

This image of galaxy cluster Abell 2744, also called Pandora's Cluster, was taken by the Spitzer Space Telescope. The gravity of this galaxy cluster is strong enough that it acts as a lens to magnify images of more distant background galaxies. This technique is called gravitational lensing. The fuzzy blobs in this Spitzer image are the massive galaxies at the core of this cluster, but astronomers will be poring over the images in search of the faint streaks of light created where the cluster magnifies a distant background galaxy. The cluster is also being studied by NASA's Hubble Space Telescope and Chandra X-Ray Observatory in a collaboration called the Frontier Fields project. In this image, light from Spitzer's infrared channels is colored blue at 3.6 microns and green at 4.5 microns.

Astronomers have made the most detailed study yet of an extremely massive young galaxy cluster using three of NASA's Great Observatories. This multi-wavelength image shows this galaxy cluster, called IDCS J1426.5+3508 (IDCS 1426 for short), in X-rays recorded by the Chandra X-ray Observatory in blue, visible light observed by the Hubble Space Telescope in green, and infrared light detected by the Spitzer Space Telescope in red. This rare galaxy cluster, which is located 10 billion light-years from Earth, is almost as massive as 500 trillion suns. This object has important implications for understanding how such megastructures formed and evolved early in the universe. The light astronomers observed from IDCS 1426 began its journey to Earth when the universe was less than a third of its current age. It is the most massive galaxy cluster detected at such an early time. First discovered by the Spitzer Space Telescope in 2012, IDCS 1426 was then observed using the Hubble Space Telescope and the Keck Observatory to determine its distance. Observations from the Combined Array for Millimeter-wave Astronomy indicated it was extremely massive. New data from the Chandra X-ray Observatory confirm the galaxy cluster's mass and show that about 90 percent of this mass is in the form of dark matter -- the mysterious substance that has so far been detected only through its gravitational pull on normal matter composed of atoms. There is a region of bright X-ray emission (seen as blue-white) near the middle of the cluster, but not exactly at the center. The location of this "core" of gas suggests that the cluster may have had a collision or interaction with another massive system of galaxies relatively recently, perhaps within about the last 500 million years. This would cause the core to slosh around like wine in a moving glass and become offset, as it appears to be in the Chandra data. Such a merger would not be surprising, given that astronomers are observing IDCS 1426 when the universe was only 3.8 billion years old. Scientists think that, in order for such an enormous structure to form so rapidly, mergers with smaller clusters would likely play a role in the large cluster's growth. In addition, while still extremely hot, the bright core contains cooler gas than its surroundings. This is the most distant galaxy cluster where such a "cool core" of gas has been observed. Astronomers think these cool cores are important in understanding how quickly hot gas cools off in clusters, influencing the rate at which stars are born. This cooling rate could be slowed down by outbursts from a supermassive black hole in the center of the cluster. Apart from the cool core, the hot gas in the cluster is remarkably symmetrical and smooth. This is another piece of evidence that IDCS 1426 formed very rapidly in the early universe. Astronomers note that, despite the high mass and rapid evolution of this cluster, its existence does not pose a threat to the standard model of cosmology.