This artist's concept shows a hypothetical "rejuvenated" planet -- a gas giant that has reclaimed its youthful infrared glow. NASA's Spitzer Space Telescope found tentative evidence for one such planet around a dead star, or white dwarf, called PG 0010+280 (depicted as white dot in illustration). When planets are young, they are warm and toasty due to internal heat left over from their formation. Planets cool over time -- until they are possibly rejuvenated. The theory goes that this Jupiter-like planet, which orbits far from its star, would accumulate some of the material sloughed off by its star as the star was dying. The material would cause the planet to swell in mass. As the material fell onto the planet, it would heat up due to friction and glow with infrared light. The final result would be an old planet, billions of years in age, radiating infrared light as it did in its youth. Spitzer detected an excess infrared light around the white dwarf PG 0010+280. Astronomers aren't sure where the light is coming from, but one possibility is a rejuvenated planet. Future observations may help solve the mystery. A Jupiter-like planet is about ten times the size of a white dwarf. White dwarfs are about the size of Earth, so one white dwarf would easily fit into the Great Red Spot on Jupiter!

This diagram illustrates how hypothetical helium atmospheres might form. These would be on planets about the mass of Neptune, or smaller, which orbit tightly to their stars, whipping around in just days. They are thought to have cores of water or rock, surrounded by thick atmospheres of gas. Radiation from their nearby stars would boil off hydrogen and helium, but because hydrogen is lighter, more hydrogen would escape. It's also possible that planetary bodies, such as asteroids, could impact the planet, sending hydrogen out into space. Over time, the atmospheres would become enriched in helium. With less hydrogen in the planets' atmospheres, the concentration of methane and water would go down. Both water and methane consist in part of hydrogen. Eventually, billions of years later (a "Gyr" equals one billion years), the abundances of the water and methane would be greatly reduced. Since hydrogen would not be abundant, the carbon would be forced to pair with oxygen, forming carbon monoxide. NASA's Spitzer Space Telescope observed a proposed helium planet, GJ 436b, with these traits: it lacks methane, and appears to contain carbon monoxide. Future observations are needed to detect helium itself in the atmospheres of these planets, and confirm this theory.

Planets having atmospheres rich in helium may be common in our galaxy, according to a new theory based on data from NASA's Spitzer Space Telescope. These planets would be around the mass of Neptune, or lighter, and would orbit close to their stars, basking in their searing heat. According to the new theory, radiation from the stars would boil off hydrogen in the planets' atmospheres. Both hydrogen and helium are common ingredients of gas planets like these. Hydrogen is lighter than helium and thus more likely to escape. After billions of years of losing hydrogen, the planet's atmosphere would become enriched with helium. Scientists predict the planets would appear covered in white or gray clouds. This is in contrast to our own Neptune, which is blue due to the presence of methane. Methane absorbs the color red, leaving blue. Neptune is far from our sun and hasn't lost its hydrogen. The hydrogen bonds with carbon to form methane. This artist's concept depicts a proposed helium-atmosphere planet called GJ 436b, which was found by Spitzer to lack in methane -- a first clue about its lack of hydrogen. The planet orbits every 2.6 days around its star, which is cooler than our sun and thus appears more yellow-orange in color.

This artists impression of super-Earth 55 Cancri e shows a hot partially-molten surface of the planet before and after possible volcanic activity on the day side. Using NASAs Spitzer Space Telescope, the researchers observed thermal emissions coming from the planet, called 55 Cancri e orbiting a sun-like star located 40 light years away in the Cancer constellation and for the first time found rapidly changing conditions, with temperatures on the hot day side of the planet swinging between 1000 and 2700 degrees Celsius. Although the interpretations of the new data are still preliminary, the researchers believe the variability in temperature could be due to huge plumes of gas and dust which occasionally blanket the surface, which may be partially molten. The plumes could be caused by exceptionally high rates of volcanic activity, higher than what has been observed on Io, one of Jupiters moons and the most geologically active body in the solar system. The full University of Cambridge release can be found here: http://www.cam.ac.uk/research/news/astronomers-find-first-evidence-of-changing-conditions-on-a-super-earth

This infographic explains how NASA's Spitzer Space Telescope can be used in tandem with a telescope on the ground to measure the distances to planets discovered using the "microlensing" technique.

Astronomers have discovered one of the most distant planets known, a gas giant about 13,000 light-years from Earth, called OGLE-2014-BLG-0124L. The planet was discovered using a technique called microlensing, and the help of NASA's Spitzer Space Telescope and the Optical Gravitational Lensing Experiment, or OGLE. In this artist's illustration, planets discovered with microlensing are shown in yellow. The farthest lies in the center of our galaxy, 25,000 light-years away. Most of the known exoplanets, numbering in the thousands, have been discovered by NASA's Kepler space telescope, which uses a different strategy called the transit method. Kepler's cone-shaped field of view is shown in pink/orange. Ground-based telescopes, which use the transit and other planet-hunting methods, have discovered many exoplanets close to home, as shown by the pink/orange circle around the sun.

This plot shows data obtained from NASA's Spitzer Space Telescope and the Optical Gravitational Lensing Experiment, or OGLE, telescope located in Chile, during a "microlensing" event. Microlensing events occur when one star passes another, and the gravity of the foreground star causes the distant star's light to magnify and brighten. This magnification is evident in the plot, as both Spitzer and OGLE register an increase in the star's brightness. If the foreground star is circled by a planet, the planets gravity can alter the magnification over a shorter period, seen in the plot in the form of spikes and a dip. The great distance between Spitzer, in space, and OGLE, on the ground, meant that Spitzer saw this particular microlensing event before OGLE. The offset in the timing can be used to measure the distance to the planet. In this case, the planet, called OGLE-2014-BLG-0124L, was found to be 13,000 light-years away, near the center of our Milky Way galaxy. The finding was the result of fortuitous timing because Spitzer's overall program to observe microlensing events was only just starting up in the week before the planet's effects were visible from Spitzers vantage point. While Spitzer sees infrared light of 3.6 microns in wavelength, OGLE sees visible light of 0.8 microns.

Infrared images from instruments at Kitt Peak National Observatory (left) and NASA's Spitzer Space Telescope document the outburst of HOPS 383, a young protostar in the Orion star-formation complex. The background is a wide view of the region taken from a Spitzer four-color infrared mosaic. NASA's Jet Propulsion Laboratory, Pasadena, California, 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.

Volunteers using the web-based Milky Way Project brought star-forming features nicknamed "yellowballs" to the attention of researchers, who later showed that they are a phase of massive star formation. The yellow balls -- which are several hundred to thousands times the size of our solar system -- are pictured here in the center of this image of the W33 Star forming region taken by NASA's Spitzer Space Telescope. Infrared light has been assigned different colors; yellow occurs where green and red overlap. The yellow balls represent an intermediary stage of massive star formation that takes place before massive stars carve out cavities in the surrounding gas and dust (seen as green-rimmed bubbles with red interiors in this image). Infrared light of 3.6 microns is blue; 8-micron light is green; and 24-micron light is red.

This series of images show three evolutionary phases of massive star formation, as pictured in infrared images from NASA's Spitzer Space Telescope. The stars start out in thick cocoon of dust (left), evolve into hotter features dubbed "yellowballs" (center); and finally, blow out cavities in the surrounding dust and gas, resulting in green-rimmed bubbles with red centers (right). The process shown here takes roughly a million years. Even the oldest phase shown here is fairly young, as massive stars live a few million years. Eventually, the stars will migrate away from their birth clouds. In this image, infrared light of 3.6 microns is blue; 8-micron light is green; and 24-micron light is red.

The Horsehead is only one small feature in the Orion Molecular Cloud Complex, dominated in the center of this view by the brilliant Flame nebula (NGC 2024). The smaller, glowing cavity falling between the Flame nebula and the Horsehead is called NGC 2023. These regions are about 1,200 light-years away. The two carved-out cavities of the Flame nebula and NGC 2023 were created by the destructive glare of recently formed massive stars within their confines. They can be seen tracing a spine of glowing dust that runs through the image. The Flame nebula sits adjacent to the star Alnitak, the easternmost star in Orions belt, seen here as the bright blue dot near the top of the nebula. In this infrared image from Spitzer, blue represents light emitted at a wavelength of 3.6-microns, and cyan (blue-green) represents 4.5-microns, both of which come mainly from hot stars. Green represents 8-micron light and red represents 24-micron light. Relatively cooler objects, such as the dust of the nebulae, appear green and red. Some regions along the top and bottom of the image extending beyond Spitzer's observations were filled in using data from NASA's Wide-field Infrared Survey Explorer, or WISE, which covered similar wavelengths across the whole sky.

The famous Horsehead nebula seen in visible-light images (inset) looks quite different when viewed in infrared light, as seen in this newly released image from NASA's Spitzer Space Telescope. The visible-light image, from the European Southern Observatorys Very Large Telescope facility, can be found online at http://www.eso.org/public/images/eso0202a/.

At this time of year, holiday parties often include festive lights. When galaxies get together, they also may be surrounded by a spectacular light show. That's the case with NGC 2207 and IC 2163, which are located about 130 million light-years from Earth, in the constellation of Canis Major. This pair of spiral galaxies has been caught in a grazing encounter. NGC 2207 and IC 2163 have hosted three supernova explosions in the past 15 years and have produced one of the most bountiful collections of super-bright X-ray lights known. These special objects -- known as "ultraluminous X-ray sources" (ULXs) -- have been found using data from NASA's Chandra X-Ray Observatory. This composite image of NGC 2207 and IC 2163 contains Chandra data in pink, optical-light data from NASA's Hubble Space Telescope visible-light data in blue, white, orange and brown, and infrared data from NASA's Spitzer Space Telescope in red.

A new feature in the evolution of galaxies has been captured in this image of galactic interactions. The two galaxies seen here -- NGC 3226 at the top, NGC 3227 at the bottom -- are awash in the remains of a departed third galaxy, cannibalized by the gravity of the surviving galaxies. The surge of warm gas flowing into NGC 3226, seen as a blue filament, appears to be shutting down this galaxy's star formation, disrupting the cool gas needed to make fresh stars. The findings come courtesy of the European Space Agency's Herschel space observatory, in which NASA played a key role, and NASA's Spitzer and Hubble space telescopes. Adding material to galaxies often rejuvenates them, triggering new rounds of star birth as gas and dust gel together. Yet data from the three telescopes all indicate that NGC 3226 has a very low rate of star formation. In this instance, material falling into NGC 3226 is heating up as it collides with other galactic gas and dust, quenching star formation instead of fueling it. As this warm gas chills out in the future, though, NGC 3226 should get a second wind in its stalled-out production of new stars. The gray scale in this image shows optical starlight captured by the MegaCam instrument at the Canada France Hawaii Telescope (CFHT) telescope on Mauna Kea in Hawaii, and reveals loops of stars flung about by the galactic cannibalism. The blue color represents cool hydrogen gas seen in radio waves by the Very Large Array near Socorro, New Mexico. The big plume of gas above NGC 3226 is being drawn into the galaxy by its gravity. The red color shows infrared light emissions, captured by Spitzer, from warm gas and dust at the tip of the plume's infalling stream of material into NGC 3226, as well as from features within NGC 3227. Other Spitzer observations reveal a disk of warm molecular gas at the core of NGC 3226, fed by the plume. Herschel observations, not shown in the image, were used to create a galactic star-formation model, which confirms NGC 3226's very low star-formation rate. The interacting galaxies are located 49 million light-years away in the constellation Leo. Visible starlight at wavelengths of 550 to 700 nanometers is shown in gray scale. The infrared glow of dust at 8 microns, as seen by Spitzer, is displayed in red, while the radio glow of hydrogen gas at 21 centimeters, from the VLA, is shown in blue.

A new feature in the evolution of galaxies has been captured in this image of galactic interactions. The two galaxies seen here -- NGC 3226 at the top (and in call-out to right), NGC 3227 at the bottom -- are awash in the remains of a departed third galaxy, cannibalized by the gravity of the surviving galaxies. The surge of warm gas flowing into NGC 3226, seen as a blue filament, appears to be shutting down this galaxy's star formation, disrupting the cool gas needed to make fresh stars. The findings come courtesy of the European Space Agency's Herschel space observatory, in which NASA played a key role, and NASA's Spitzer and Hubble space telescopes. Adding material to galaxies often rejuvenates them, triggering new rounds of star birth as gas and dust gel together. Yet data from the three telescopes all indicate that NGC 3226 has a very low rate of star formation. In this instance, material falling into NGC 3226 is heating up as it collides with other galactic gas and dust, quenching star formation instead of fueling it. As this warm gas chills out in the future, though, NGC 3226 should get a second wind in its stalled-out production of new stars. The gray scale in this image shows optical starlight captured by the MegaCam instrument at the Canada France Hawaii Telescope (CFHT) telescope on Mauna Kea in Hawaii, and reveals loops of stars flung about by the galactic cannibalism. The blue color represents cool hydrogen gas seen in radio waves by the Very Large Array near Socorro, New Mexico. The big plume of gas above NGC 3226 is being drawn into the galaxy by its gravity. The red color shows infrared light emissions, captured by Spitzer, from warm gas and dust at the tip of the plume's infalling stream of material into NGC 3226, as well as from features within NGC 3227. Other Spitzer observations reveal a disk of warm molecular gas at the core of NGC 3226, fed by the plume. Herschel observations, not shown in the image, were used to create a galactic star-formation model, which confirms NGC 3226's very low star-formation rate. The interacting galaxies are located 49 million light-years away in the constellation Leo. Visible starlight at wavelengths of 550 to 700 nanometers is shown in gray scale. The infrared glow of dust at 8 microns, as seen by Spitzer, is displayed in red, while the radio glow of hydrogen gas at 21 centimeters, from the VLA, is shown in blue.

This diagram illustrates two similar star systems, HD 95086 and HR 8799. Evidence from NASA's Spitzer Space Telescope has pointed to the presence of two dust belts in each system: warm, inner belts similar to our solar system's asteroid belt, and cool, outer belts like our Kuiper belt of icy comets. Data from Spitzer and the European Space Agency's Hershel space observatory, in which NASA plays a role, also found extended halos of fine dust around both stars. While HR 8799 has four giant planets known to circle between its two belts, HD 95068 has only one -- at least that is known of so far. The similarities between both systems hint that HD 95068 may also have multiple planets hiding between its two belts. HD 95086 and HR 8799 are located 295 and 129 light-years from Earth in the constellations of Carina and Pegasus, respectively. 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.

A new image from NASA's Spitzer Space Telescope, taken in infrared light, shows where the action is taking place in galaxy NGC 1291. The outer ring, colored red in this view, is filled with new stars that are igniting and heating up dust that glows with infrared light. The stars in the central area produce shorter-wavelength infrared light than that seen in the ring, and are colored blue. This central area is where older stars live, having long ago gobbled up the available gas supply, or fuel, for making new stars. The galaxy is about 12 billion years old and is located 33 million light years away in the Eridanus constellation. It is known as a barred galaxy because a central bar of stars (which looks like a blue "S" in this view) dominates its center. When galaxies are young and gas-rich, stellar bars drive gas toward the center, feeding star formation. Over time, as the star-making fuel runs out, the central regions become quiescent and star-formation activity shifts to the outskirts of a galaxy. There, spiral density waves and resonances induced by the central bar help convert gas to stars. The outer ring, seen here in red, is one such resonance location, where gas has been trapped and ignited into a star-forming frenzy. 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 ghostly structures highlighting the peculiar patterns of orbiting stars in the center of the galaxy NGC 1292 stand out vividly in this specially-processed image from NASA's Spitzer Space Telescope. By making detailed observations of the galaxy in infrared light, astronomers can tease out the hidden details of the strange dynamics in this barred galaxy. The galaxy is about 12 billion years old and is located 33 million light years away in the Eridanus constellation. It is known as a barred galaxy because a central bar of stars (which looks like a blue "S" in this view) dominates its center. When galaxies are young and gas-rich, stellar bars drive gas toward the center, feeding star formation. Over time, as the star-making fuel runs out, the central regions become quiescent and star-formation activity shifts to the outskirts of a galaxy. There, spiral density waves and resonances induced by the central bar help convert gas to stars. The outer ring is one such resonance location, where gas has been trapped and ignited into a star-forming frenzy. This image has been processed to suppress the smooth glow of starlight that fills the center of this galaxy, enhancing our view of the peculiar structure in this region. These spokes and clumps are essentially stellar traffic jams, formed by the convoluted orbits of the billions of stars bunching up as they move through the central bar. Close examination of the outer ring reveals that it is actually composed of two distinct arcs that partially blend into one another. Infrared light at wavelengths of 3.4 and 4.5 microns are rendered in blue and green, combining into a single cyan tone showing the distribution of stars.

A small galaxy, called Sextans A, is shown here in a multi-wavelength mosaic captured by the European Space Agency's Herschel mission, in which NASA is a partner, along with NASA's Galaxy Evolution Explorer (GALEX) and the National Radio Astronomy Observatory's Jansky Very Large Array observatory near Socorro, New Mexico. The galaxy is located 4.5 million light-years from Earth in the Sextans constellation. The environment in this galaxy is similar to that of our infant universe because it lacks in heavy metals, or elements heavier than hydrogen and helium. Heavy metals act in some ways like fertilizers for stars, helping them form and grow. Scientists study galaxies like Sextans A to learn how stars still manage to slowly bloom under these poor-growing conditions. The research provides a better understanding of how the very first stars in our universe came to be. In this image, the purple shows gas; blue shows young stars and the orange and yellow dots are newly formed stars heating up dust.

Scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA's Hubble, Spitzer and Kepler space telescopes. The view from this planet -- were it possible to fly a spaceship into its gaseous layers -- is illustrated here. The clear planet, called HAT-P-11b, is gaseous with a rocky core, much like our own Neptune. Its atmosphere may have clouds deeper down, but the new observations show that the upper region is cloud-free. This good visibility enabled scientists to detect water vapor molecules in the planet's atmosphere.

Scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA's Hubble, Spitzer and Kepler space telescopes. The view from this planet -- were it possible to fly a spaceship into its gaseous layers -- is illustrated at right. Before now, all of the planets observed in this size range had been found to have high cloud layers that blocked the ability to detect molecules in the planet's atmosphere (illustrated at left). The clear planet, called HAT-P-11b, is gaseous with a rocky core, much like our own Neptune. Its atmosphere may have clouds deeper down, but the new observations show that the upper region is cloud-free. This good visibility enabled scientists to detect water vapor molecules in the planet's atmosphere.

A Neptune-size planet with a clear atmosphere is shown crossing in front of its star in this artist's depiction. Such crossings, or transits, are observed by telescopes like NASA's Hubble and Spitzer to glean information about planets' atmospheres. As starlight passes through a planet's atmosphere, atoms and molecules absorb light at certain wavelengths, blocking it from the telescope's view. The more light a planet blocks, the larger the planet appears. By analyzing the amount of light blocked by the planet at different wavelengths, researchers can determine which molecules make up the atmosphere. The problem with this technique is that sometimes planets have thick clouds that block any light from coming through, hiding the signature of the molecules in the atmosphere. This is particularly true of the handful of Neptune-size and super-Earth planets examined to date, all of which appear to be cloudy. As a result, astronomers were elated to find clear skies on a Neptune-size planet called HAT-P-11b, as illustrated here. Without clouds to block their view, they were able to identify water vapor molecules in the planet's atmosphere. The blue rim of the planet in this image is due to scattered light, while the orange rim on the part of the planet in front of the star indicates the region where water vapor was detected.

A plot of the transmission spectrum for exoplanet HAT-P-11b, with data from NASA's Kepler, Hubble and Spitzer observatories combined. The results show a robust detection of water absorption in the Hubble data. Transmission spectra of selected atmospheric models are plotted for comparison.

Scientists were excited to discover clear skies on a relatively small planet, about the size of Neptune, using the combined power of NASA's Hubble, Spitzer and Kepler space telescopes. Before now, all of the planets observed in this size range had been found to have high cloud layers that blocked the ability to detect molecules in the planet's atmosphere. The clear planet, called HAT-P-11b, is gaseous with a rocky core, much like our own Neptune. Its atmosphere may have clouds deeper down, but the new observations show that the upper region is cloud-free. This good visibility enabled scientists to detect water vapor molecules in the planet's atmosphere.

Millions of galaxies populate the patch of sky known as the COSMOS field, short for Cosmic Evolution Survey, a portion of which is shown here. Even the smallest dots in this image are galaxies, some up to 12 billion light-years away. The square region in the center of bright objects is where the telescope was blinded by bright light. However, even these brightest objects in the field are more than ten thousand times fainter than what you can see with the naked eye. The picture is a combination of infrared data from Spitzer (red) and visible-light data (blue and green) from Japan's Subaru telescope atop Mauna Kea in Hawaii. These data were taken as part of the SPLASH (Spitzer large area survey with Hyper-Suprime-Cam) project.

Scientists "fish" for galaxies in this playful, digitally altered photo. The researchers are part of a program called SPLASH, which is using NASA's Spitzer Space Telescope to dive deep into the cosmic sea and find some of the most remote galaxies known. Early results are turning up surprisingly big "fish" -- massive galaxies -- in the darkest reaches of the universe, dating back to a time when our universe was less than one billion years old. The researchers from left to right are: Peter Capak and Charles Steinhardt of NASA's Infrared Processing and Analysis Center (IPAC) at the California Institute of Technology in Pasadena, and Josh Speagle from Harvard University, Cambridge, Massachusetts. SPLASH, an international effort, stands for Spitzer Large Area Survey with Hyper-Suprime-Cam.

Astronomers were surprised to see these data from NASA's Spitzer Space Telescope in January 2013, showing a huge eruption of dust around a star called NGC 2547-ID8. In this plot, infrared brightness is represented on the vertical axis, and time on the horizontal axis. The data at left show infrared light from the dust around the star back in 2012. Between 2012 and 2013, Spitzer had to stop observing the star because it was located behind the sun, as seen from Spitzer's Earth-trailing orbit. When Spitzer began watching the star again in January 2013, the astronomers noticed a huge jump in the data. (The red and blue data plots show different infrared wavelengths.) Why the dramatic change? The team says that dust in the star system surged intensely, likely after two large asteroids collided, kicking up fresh dust. The periodic variability of the signal is caused by the remaining dust cloud in orbit around the star. This dust cloud is elongated, so the amount of infrared signal it produces changes as it circles the star from our point of view. The infrared signal is decreasing over time as dust from the collision is ground down to finer sizes and blown of the system.

Planets, including those like our own Earth, form from epic collisions between asteroids and even bigger bodies, called proto-planets. Sometimes the colliding bodies are ground to dust, and sometimes they stick together to ultimately form larger, mature planets. This artist's conception shows one such smash-up, the evidence for which was collected by NASA's Spitzer Space Telescope. Spitzer's infrared vision detected a huge eruption around the star NGC 2547-ID8 between August 2012 and 2013. Scientists think the dust was kicked up by a massive collision between two large asteroids. They say the smashup took place in the star's "terrestrial zone," the region around stars where rocky planets like Earth take shape. NGC 2547-ID8 is a sun-like star located about 1,200 light-years from Earth in the constellation Vela. It is about 35 million years old, the same age our young sun was when its rocky planets were finally assembled via massive collisions -- including the giant impact on proto-Earth that led to the formation of the moon. The recent impact witnessed by Spitzer may be a sign of similar terrestrial planet building. Near-real-time studies like these help astronomers understand how the chaotic process works.

This illustration reveals the celestial fireworks deep inside the crowded core of a developing galaxy, as seen from a hypothetical planetary system consisting of a bright, white star and single planet. The sky is ablaze with the glow from nebulae, fledgling star clusters, and stars exploding as supernovae. The rapidly forming core may eventually become the heart of a mammoth galaxy similar to one of the giant elliptical galaxies seen today.

The destructive results of a mighty supernova explosion reveal themselves in a delicate blend of infrared and X-ray light, as seen in this image from NASAs Spitzer Space Telescope and Chandra X-Ray Observatory, and the European Space Agency's XMM-Newton. The bubbly cloud is an irregular shock wave, generated by a supernova that would have been witnessed on Earth 3,700 years ago. The remnant itself, called Puppis A, is around 7,000 light-years away, and the shock wave is about 10 light-years across. The pastel hues in this image reveal that the infrared and X-ray structures trace each other closely. Warm dust particles are responsible for most of the infrared light wavelengths, assigned red and green colors in this view. Material heated by the supernovas shock wave emits X-rays, which are colored blue. Regions where the infrared and X-ray emissions blend together take on brighter, more pastel tones. The shock wave appears to light up as it slams into surrounding clouds of dust and gas that fill the interstellar space in this region. From the infrared glow, astronomers have found a total quantity of dust in the region equal to about a quarter of the mass of our sun. Data collected from Spitzers infrared spectrograph reveal how the shock wave is breaking apart the fragile dust grains that fill the surrounding space. Supernova explosions forge the heavy elements that can provide the raw material from which future generations of stars and planets will form. Studying how supernova remnants expand into the galaxy and interact with other material provides critical clues into our own origins. Infrared data from Spitzers multiband imaging photometer (MIPS) at wavelengths of 24 and 70 microns are rendered in green and red. X-ray data from XMM-Newton spanning an energy range of 0.3 to 8 keV (kiloelectron volts) are shown in blue.