A storm of stars is brewing in the Trifid nebula, as seen in this view from NASA's Wide-field Infrared Survey Explorer, or WISE. The stellar nursery, where baby stars are bursting into being, is the yellow-and-orange object dominating the picture. Yellow bars in the nebula appear to cut a cavity into three sections, hence the name Trifid nebula. Colors in this image represent different wavelengths of infrared light detected by WISE. The main green cloud is made up of hydrogen gas. Within this cloud is the Trifid nebula, where radiation and winds from massive stars have blown a cavity into the surrounding dust and gas, and presumably triggered the birth of new generations of stars. Dust glows in infrared light, so the three lines that make up the Trifid, while appearing dark in visible-light views, are bright when seen by WISE. The blue stars scattered around the picture are older, and they lie between Earth and the Trifid nebula. The baby stars in the Trifid will eventually look similar to those foreground stars. The red cloud at upper right is gas heated by a group of very young stars. The Trifid nebula is located 5,400 light-years away in the constellation Sagittarius. Blue represents light emitted at 3.4-micron wavelengths, and cyan (blue-green) represents 4.6 microns, both of which come mainly from hot stars. Relatively cooler objects, such as the dust of the nebula, appear green and red. Green represents 12-micron light and red, 22-micron light. Caption: NASA

This landscape scene photographed by NASA's Curiosity Mars rover shows rows of rocks in the foreground and Mount Sharp on the horizon. Curiosity's Navigation Camera (Navcam) took the component images for this mosaic during a pause in driving on the 548th Martian day, or sol, of the rover's work on Mars (Feb. 19, 2014). The Sol 548 drive covered 328 feet (100 meters). Images taken from orbit and used in planning the rover's route toward lower slopes of Mount Sharp had piqued researchers interest in the striations on the ground that are formed by these rows of rocks. This particular outcrop is called "Junda." Similar striations are apparent on other patches of ground along the planned route. The view is centered toward south-southeast and spans about 160 degrees. It is presented as a cylindrical projection. Caption: NASA/JPL

Stephan's Quintet, a compact group of galaxies discovered about 130 years ago and located about 280 million light years from Earth, provides a rare opportunity to observe a galaxy group in the process of evolving from an X-ray faint system dominated by spiral galaxies to a more developed system dominated by elliptical galaxies and bright X-ray emission. Being able to witness the dramatic effect of collisions in causing this evolution is important for increasing our understanding of the origins of the hot, X-ray bright halos of gas in groups of galaxies. Caption: NASA

Just weeks after NASA's Chandra X-ray Observatory began operations in 1999, the telescope pointed at Centaurus A (Cen A, for short). This galaxy, at a distance of about 12 million light years from Earth, contains a gargantuan jet blasting away from a central supermassive black hole. Since then, Chandra has returned its attention to this galaxy, each time gathering more data. And, like an old family photo that has been digitally restored, new processing techniques are providing astronomers with a new look at this old galactic friend. This new image of Cen A contains data from observations, equivalent to over nine and a half days worth of time, taken between 1999 and 2012. In this image, the lowest-energy X-rays Chandra detects are in red, while the medium-energy X-rays are green, and the highest-energy ones are blue. As in all of Chandra's images of Cen A, this one shows the spectacular jet of outflowing material - seen pointing from the middle to the upper left - that is generated by the giant black hole at the galaxy's center. This new high-energy snapshot of Cen A also highlights a dust lane that wraps around the waist of the galaxy. Astronomers think this feature is a remnant of a collision that Cen A experienced with a smaller galaxy millions of years ago. The data housed in Chandra's extensive archive on Cen A provide a rich resource for a wide range of scientific investigations. For example, researchers published findings in 2013 on the point-like X-ray sources in Cen A. Most of these sources are systems where a compact object - either a black hole or a neutron star - is pulling gas from an orbiting companion star. These compact objects form by the collapse of massive stars, with black holes resulting from heavier stars than neutron stars. The results suggested that nearly all of the compact objects had masses that fell into two categories: either less than twice that of the Sun, or more than five times as massive as the Sun. These two groups correspond to neutron stars and black holes. This mass gap may tell us about the way massive stars explode. Scientists expect an upper limit on the most massive neutron stars, up to twice the mass of the Sun. What is puzzling is that the smallest black holes appear to weigh in at about five times the mass of the Sun. Stars are observed to have a continual range of masses, and so in terms of their progeny's weight we would expect black holes to carry on where neutron stars left off. Although this mass gap between neutron stars and black holes has been seen in our galaxy, the Milky Way, this new Cen A result provides the first hints that the gap occurs in more distant galaxies. If it turns out to be ubiquitous, it may mean that a special, rapid type of stellar collapse is required in some supernova explosions. Caption: Chandra Telescope Team

Russell Crater dunes are a favorite target for HiRISE images not only because of their incredible beauty, but for how we can measure the accumulation of frost year after year in the fall, and its disappearance in the spring. The frost is, of course, carbon dioxide ice that often sublimates (going directly from a solid to a gas) during the Martian spring. HiRISE takes images of the same areas on Mars in order to study seasonal changes like this. In an area like Russell Crater--a very ancient impact crater about 140 kilometers in diameter--we can follow changes in the terrain by comparing images taken at different times. This helps give us a better understanding of active processes on the Red Planet. Caption: HirRISE Science Team

This scene combines images taken by the left-eye camera of the Mast Camera (Mastcam) instrument on NASA's Curiosity Mars rover during the midafternoon, local Mars solar time, of the mission's 526th Martian day, or sol (Jan. 28, 2014). The sand dune in the upper center of the image spans a gap, called "Dingo Gap," between two short scarps. The dune is about 3 feet (1 meter) high. The nearer edge of it is about 115 feet (35 meters) away from the rover's position when the component images were taken, just after a Sol 526 drive of 49 feet (15 meters). The image has been white-balanced to show what the rocks would look like if they were on Earth. A version with 200-centimeter (79-inch) scale bars is available as Figure A. Caption: NASA

The largest sunspot group of the solar cycle unleashed a large (X1.2 class) flare just when it was facing right towards Earth (Jan. 7, 2014). The flare was associated with a coronal mass ejection that was heading in our direction and could generate some bright aurora here when it impacts our magnetosphere. More flares are expected from this magnetically complex region in the next week or so: stay tuned! These images were produced using a combination of two wavelengths of extreme ultraviolet light. Caption: NASA/SDO

Floating at the center of this new Hubble image is a lidless purple eye, staring back at us through space. This ethereal object, known officially as [SBW2007] 1 but sometimes nicknamed SBW1, is a nebula with a giant star at its center. The star was originally twenty times more massive than our sun, and is now encased in a swirling ring of purple gas, the remains of the distant era when it cast off its outer layers via violent pulsations and winds. But the star is not just any star; scientists say that it is destined to go supernova. Twenty-six years ago, another star with striking similarities went supernova — SN 1987A. Early Hubble images of SN 1987A show eerie similarities to SBW1. Both stars had identical rings of the same size and age, which were travelling at similar speeds; both were located in similar HII regions; and they had the same brightness. In this way SBW1 is a snapshot of SN1987a's appearance before it exploded, and unsurprisingly, astronomers love studying them together.

At a distance of more than 20 000 light-years it will be safe to watch when the supernova goes off. If we are very lucky it may happen in our own lifetimes. Caption: NASA

The closest supernova of its kind to be observed in the last few decades has sparked a global observing campaign involving legions of instruments on the ground and in space, including NASA's Spitzer Space Telescope. This image shows Spitzer's view of the supernova's host galaxy, M82 or the "Cigar galaxy," on three separate dates: May 9, 2005; February 7, 2014; and February 12, 2014. The observations from February 7 reveal the presence of a bright spot -- the supernova -- not present in the prior observations. By February 12, the supernova has started to dim somewhat from its peak brightness in the first week of February. The supernova, dubbed SN 2014J, was first spotted by human observers on January 21, 2014. SN 2014J is glowing very brightly in the infrared light that Spitzer sees. The telescope was able to observe the supernova before and after it reached its peak brightness. Such early observations with an infrared telescope have only been obtained for a few Type Ia supernovas in the past. Dust in the M82 galaxy partially obscures observations in optical and high-energy forms of light. The infrared light that Spitzer sees in, however, can pass through this dust, allowing astronomers to peer directly into the heart of the aftermath of the stellar explosion. Caption: NASA

This look back at a dune that NASA's Curiosity Mars rover drove across was taken by the rover's Mast Camera (Mastcam) during the 538th Martian day, or sol, of Curiosity's work on Mars (Feb. 9, 2004). The rover had driven over the dune three days earlier. For scale, the distance between the parallel wheel tracks is about 9 feet (2.7 meters). The dune is about 3 feet (1 meter) tall in the middle of its span across an opening called "Dingo Gap." This view is looking eastward. The image has been white balanced to show what the Martian surface materials would look like if under the light of Earth's sky. A version with raw color, as recorded by the camera under Martian lighting conditions, is available as Figure 1. Caption: NASA/JPL

NGC 2276 and NGC 2300 are "boundary" targets in that they are the northernmost objects in the New General Catalog of space stuff. Being this close to the north celestial pole (and Polaris) makes them challenging targets for equatorial telescopes. NGC 2276 is a beautiful spiral galaxy that is punctuated by pink star forming regions. In fact it has one of the highest rates of star formation that has been measured. Its neighbor, NGC 2300, appears as a regular elliptical galaxy that shows some evidence of shells (and perhaps former structure). Together these make a wonderful contrast at the boundaries of space and time. From my southern-mid-latitude the celestial pole is a mere 32 degrees above the horizon. Which means that although this field is always available- it is never high in the sky the challenges the telescope to point at it. Finally the field also contains some of the foreground galactic cirrus (IFN) that pervade these high declinations. Perhaps you can see hints of it at the bottom left. P.S. As far as I know, my statement is correct concerning NGC 2276 being the northernmost NGC object. The more famous cluster of NGC 188 is just a bit farther south. Let me know if I am mistaken. Caption: Adam Block

This wide-angle image shows the south polar region of Saturn's moon Enceladus and outlines the area covered by the high-resolution mosaic combining data from the imaging science subsystem and composite infrared spectrometer aboard NASA's Cassini spacecraft. The outlined area focuses on Baghdad Sulcus, a fracture in the south polar region. Cassini captured the data for this wide-angle image during the spacecraft's close flyby of the moon Nov. 21, 2009. This image and others from that flyby are among the best visible light images Cassini will capture of the region around the "tiger stripes," -- the fissures that spray icy particles, water vapor and organic compounds -- compounds, before the moon's south polar region enters winter darkness for the coming years. This wide-angle view shows not only Baghdad Sulcus, but also other nearby fractures. Lit terrain seen here is on the leading hemisphere and Saturn-facing side of Enceladus (504 kilometers, 313 miles across). The south pole lies in shadow near the bottom middle of the image. The wide-angle view was acquired at a distance of approximately 2,000 kilometers (1,200 miles) from Enceladus and at a sun-Enceladus-spacecraft, or phase, angle of 114 degrees. Scale in the wide-angle view is 116 meters (381 feet) per pixel. Caption: Cassini Solstice Team

A collage of radar images of near-Earth asteroid 2006 DP14 was generated by NASA scientists using the 230-foot (70-meter) Deep Space Network antenna at Goldstone, Calif., on the night of Feb. 11, 2014. Delay-Doppler radar imaging revealed that the asteroid is about 1,300 feet (400 meters) long, 660 feet (200 meters) wide, and shaped somewhat like a big peanut. The asteroid's period of rotation is about six hours. The asteroid is of a type known as a "contact binary" because it has two large lobes on either end that appear to be in contact. Previous radar data from Goldstone and the Arecibo Observatory in Puerto Rico has shown that at least 10 percent of near-Earth asteroids larger than about 650 feet (200 meters) have contact binary shapes like that of 2006 DP14. The data were obtained over an interval of 2.5 hours as the asteroid completed about half a revolution. The resolution is about 60 feet (19 meters) per pixel. The data were obtained on Feb. 11 between 9:03 a.m. and 11:27 p.m. PST (12:03 a.m. to 2:27 a.m. EST on Feb. 12). At the time of the observations, the asteroid's distance was about 2.6 million miles (4.2 million kilometers) from Earth. That is about 11 times the average distance between Earth and its moon. The asteroid's closest approach to Earth occurred on Feb. 10, at a distance of about 1.5 million miles (2.4 million kilometers). Radar is a powerful technique for studying an asteroid's size, shape, rotation state, surface features and surface roughness, and for improving the calculation of asteroid orbits. While this asteroid would appear as no more than a point of light to optical telescopes, using planetary radar scientists are able to discern the physical characteristics of the asteroid and measure its exact distance from Earth. But, in order to point the enormous 230-foot (70-meter) dish antenna in the precise direction of the asteroid, numerous professional and amateur astronomers assisted in the days leading up to Feb. 11 by supplying observational data to help pinpoint the location. Radar measurements of asteroid distances and velocities often enable computation of asteroid orbits much further into the future than if radar observations weren't available. Caption: NASA/JPL

This dramatic view of the crescents of Neptune and Triton was acquired by Voyager 2 approximately 3 days, 6 and one-half hours after its closest approach to Neptune (north is to the right). The encounter put the spacecraft on a couse plunging southward at an angle of 48° to the plane of the ecliptic. This direction, combined with the current season of southern summer in the Neptune system, gives this picture its unique geometry. The spacecraft was at a distance of 4.86 million km (3 million miles) from Neptune when these images were taken so the smallest detail discernible is approximately 90 km (56 miles). Color was produced using images taken through the narrow-angle camera's clear, orange and green filters. Neptune does not appear as blue from this viewpoint because the forward scattering nature of its atmosphere is more important than its absorption of red light at this high phase angle (134°). Caption: NASA

Multiple images of a distant quasar are visible in this combined view from NASA's Chandra X-ray Observatory and the Hubble Space Telescope. The Chandra data, along with data from ESA's XMM-Newton, were used to directly measure the spin of the supermassive black hole powering this quasar. This is the most distant black hole where such a measurement has been made, as reported in our press release. Gravitational lensing by an intervening elliptical galaxy has created four different images of the quasar, shown by the Chandra data in pink. Such lensing, first predicted by Einstein, offers a rare opportunity to study regions close to the black hole in distant quasars, by acting as a natural telescope and magnifying the light from these sources. The Hubble data in red, green and blue shows the elliptical galaxy in the middle of the image, along with other galaxies in the field. The quasar is known as RX J1131-1231 (RX J1131 for short), located about 6 billion light years from Earth. Using the gravitational lens, a high quality X-ray spectrum - that is, the amount of X-rays seen at different energies - of RX J1131 was obtained. The X-rays are produced when a swirling accretion disk of gas and dust that surrounds the black hole creates a multimillion-degree cloud, or corona near the black hole. X-rays from this corona reflect off the inner edge of the accretion disk. The reflected X-ray spectrum is altered by the strong gravitational forces near the black hole. The larger the change in the spectrum, the closer the inner edge of the disk must be to the black hole. The authors of the new study found that the X-rays are coming from a region in the disk located only about three times the radius of the event horizon, the point of no return for infalling matter. This implies that the black hole must be spinning extremely rapidly to allow a disk to survive at such a small radius. This result is important because black holes are defined by just two simple characteristics: mass and spin. While astronomers have long been able to measure black hole masses very effectively, determining their spins have been much more difficult. These spin measurements can give researchers important clues about how black holes grow over time. If black holes grow mainly from collisions and mergers between galaxies they should accumulate material in a stable disk, and the steady supply of new material from the disk should lead to rapidly spinning black holes. In contrast if black holes grow through many small accretion episodes, they will accumulate material from random directions. Like a merry go round that is pushed both backwards and forwards, this would make the black hole spin more slowly. he discovery that the black hole in RX J1131 is spinning at over half the speed of light suggests that this black hole has grown via mergers, rather than pulling material in from different directions. These results were published online in the journal Nature. The lead author is Rubens Reis of the University of Michigan. His co-authors are Mark Reynolds and Jon M. Miller, also of Michigan, as well as Dominic Walton of the California Institute of Technology. Caption: Chandra Telescope Team

This image was obtained with the wide-field view of the Mosaic camera on the Mayall 4-meter telescope at Kitt Peak National Observatory. Abell 74 is an ancient planetary nebula. Because of its age it is a very faint target. Ancient planetary nebulae are often distorted in shape due to interactions with the interstellar medium. Interestingly, Abell 74 is remarkably symmetric despite its age. The image was generated with observations in the Hydrogen alpha (red) and Oxygen [OIII] (blue) filters. In this image, North is left, East is down. Caption: NOAO Please read NOAO's Conditions of Use before downloading

This series of images shows the asteroid P/2013 R3 breaking apart, as viewed by the NASA/ESA Hubble Space Telescope in 2013. This is the first time that such a body has been seen to undergo this kind of break-up. The Hubble observations showed that there are ten distinct objects, each with comet-like dust tails, embedded within the asteroid's dusty envelope. The four largest rocky fragments are up to 200 metres in radius, about twice the length of a football pitch. The dates on which the various observations were taken are marked at the bottom of each image, with frames from 29 October 2013, 15 November 2013, 13 December 2013, and 14 January 2014 respectively. The 14 January 2014 frame was not included in the science paper and is additional data. Caption: Hubble Heritage Team

A bright ice cap of frozen water covers the North Pole of Mars. In the winter, thin coverings of carbon dioxide and water frost covers this area and these frosts finally disappear at the end of the Martian spring season. In this image, the winter frosts are about to disappear and we can begin to see the surface features of the ice. The ice cap would be a bad place to get lost: it's one of the smoothest, flattest places on Mars so there are no landmarks visible. The surface features are gently rolling hummocks (or small mounds) and hollows about a meter (3 feet) in height and about 20 meters (60 feet) across. This monotonous landscape continues for hundreds of kilometers in every direction with this same repeating pattern. Scientists do not know what makes this pattern so uniform over such large distances; we acquire HiRISE images like this one to look for small differences in these icy features from one place to another. Understanding this surface can help us understand the current climate and meteorological conditions at the North Pole of the Red Planet. Caption: Shane Byrne/HiRISE

A rainbow-like feature known as a ‘glory’ has been seen by ESA’s Venus Express orbiter in the atmosphere of our nearest neighbour – the first time one has been fully imaged on another planet. Rainbows and glories occur when sunlight shines on cloud droplets – water particles in the case of Earth. While rainbows arch across wide swathes of the sky, glories are typically much smaller and comprise a series of coloured concentric rings centred on a bright core. Glories are only seen when the observer is situated directly between the Sun and the cloud particles that are reflecting sunlight. On Earth, they are often seen from aeroplanes, surrounding the shadow of the aircraft on the clouds below, or around the shadow of climbers atop misty mountain peaks.

A glory requires two characteristics: the cloud particles are spherical, and therefore most likely liquid droplets, and they are all of a similar size. The atmosphere of Venus is thought to contain droplets rich in sulphuric acid. By imaging the clouds with the Sun directly behind the Venus Express spacecraft, scientists hoped to spot a glory in order to determine important characteristics of the cloud droplets. They were successful. The glory in the images here was seen at the Venus cloud tops, 70 km above the planet’s surface, on 24 July 2011. It is 1200 km wide as seen from the spacecraft, 6000 km away. From these observations, the cloud particles are estimated to be 1.2 micrometres across, roughly a fiftieth of the width of a human hair. The fact that the glory is 1200 km wide means that the particles at the cloud tops are uniform on this scale at least. The variations of brightness of the rings of the observed glory is different than that expected from clouds of only sulphuric acid mixed with water, suggesting that other chemistry may be at play. One idea is that the cause is the “UV-absorber”, an unknown atmospheric component responsible for mysterious dark markings seen in the cloud tops of Venus at ultraviolet wavelengths. More investigation is needed to draw a firm conclusion. Caption: ESA

In this stunning picture of the giant galactic nebula NGC 3603, the crisp resolution of NASA's Hubble Space Telescope captures various stages of the life cycle of stars in one single view. To the upper left of center is the evolved blue supergiant called Sher 25. The star has a unique circumstellar ring of glowing gas that is a galactic twin to the famous ring around the supernova 1987A. The grayish-bluish color of the ring and the bipolar outflows (blobs to the upper right and lower left of the star) indicates the presence of processed (chemically enriched) material. Near the center of the view is a so-called starburst cluster dominated by young, hot Wolf-Rayet stars and early O-type stars. A torrent of ionizing radiation and fast stellar winds from these massive stars has blown a large cavity around the cluster. The most spectacular evidence for the interaction of ionizing radiation with cold molecular-hydrogen cloud material are the giant gaseous pillars to the right of the cluster. These pillars are sculptured by the same physical processes as the famous pillars Hubble photographed in the M16 Eagle Nebula. Dark clouds at the upper right are so-called Bok globules, which are probably in an earlier stage of star formation. To the lower left of the cluster are two compact, tadpole-shaped emission nebulae. Similar structures were found by Hubble in Orion, and have been interpreted as gas and dust evaporation from possibly protoplanetary disks (proplyds). This true-color picture was taken on March 5, 1999 with the Wide Field Planetary Camera 2. Caption: NASA

This new Hubble image shows spiral galaxy ESO 137-001, framed against a bright background as it moves through the heart of galaxy cluster Abell 3627. This cluster is violently ripping the spiral’s entrails out into space, leaving bright blue streaks as telltale clues to this cosmic crime. This new Hubble image shows ESO 137-001, a galaxy located in the southern constellation of Triangulum Australe (The Southern Triangle) — a delicate and beautiful spiral galaxy, but with a secret. This image not only captures the galaxy and its backdrop in stunning detail, but also something more dramatic — intense blue streaks streaming outwards from the galaxy, seen shining brightly in ultraviolet light. These streaks are actually hot young stars, encased in wispy streams of gas that are being torn away from the galaxy by its surroundings as it moves through space. This violent galactic disrobing is due to a process known as ram pressure stripping — a drag force felt by an object moving through a fluid. The fluid in question here is superheated gas, which lurks at the centres of galaxy clusters. This image also shows other telltale signs of this process, such as the curved appearance of the disc of gas and dust — a result of the forces exerted by the heated gas. The cluster's drag may be strong enough to bend ESO 137-001, but in this cosmic tug-of-war the galaxy's gravitational pull is strong enough to hold on to the majority of its dust — although some brown streaks of dust displaced by the stripping are visible. Studying ram pressure stripping helps astronomers to better understand the mechanisms that drive the evolution of galaxies. For example, it will leave this galaxy with very little of the cold gas that is essential for star formation, rendering the galaxy effectively incapable of forming new stars. Caption: Hubble Heritage Team

On Feb. 24, 2014, the sun emitted a significant solar flare, peaking at 7:49 p.m. EST. NASA's Solar Dynamics Observatory (SDO), which keeps a constant watch on the sun, captured images of the event. These SDO images from 7:25 p.m. EST on Feb. 24 show the first moments of this X-class flare in different wavelengths of light -- seen as the bright spot that appears on the left limb of the sun. Hot solar material can be seen hovering above the active region in the sun's atmosphere, the corona. Solar flares are powerful bursts of radiation, appearing as giant flashes of light in the SDO images. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel. Caption: NASA

A nearly full Rhea shines in the sunlight in this recent Cassini image. Rhea (949 miles, or 1,527 kilometers across) is Saturn's second largest moon.

Lit terrain seen here is on the Saturn-facing hemisphere of Rhea. North on Rhea is up and rotated 43 degrees to the left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 10, 2013. The view was obtained at a distance of approximately 990,000 miles (1.6 million kilometers) from Rhea. Image scale is 6 miles (9 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo. Caption: NASA

The sun emitted a mid-level solar flare, peaking at 6:34 p.m. EDT on March 12, 2014, and NASA's Solar Dynamics Observatory, or SDO, captured an image of it. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel. To see how this event may impact Earth, please visit NOAA's Space Weather Prediction Center at http://spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings. This flare is classified as an M9.3 flare, just slightly weaker than the most intense flares, which are labeled X-class. The letters denote broad categories of strength, while the numbers provide more information. An M2 is twice as intense as an M1, an M3 is three times as intense, etc. This M9.3 flare was emitted by an active region — a magnetically strong and complex region on the sun's surface — labeled AR 11996.

Updates will be provided as they are available on the flare and whether there was an associated coronal mass ejection, or CME, another solar phenomenon that can send solar particles into space and affect electronic systems in satellites and on Earth. Caption: NASA

Seen here is a jaw-dropping, amazing, stunning panorama that includes several of the most famous night sky objects, Orion's Belt and the surrounding molecular cloud. What could possibly be said to capture the sheer incredibleness of this image that isn't conveyed simply by looking at it? First of all, to set the scene, we're looking at the three stars in Orion's Belt, Alnitak, Alnilam and Mintaka, seen at left in the image. Just below Alnitak is the extremely recognizable Horsehead Nebula. Over on the right of the image is the gorgeous Orion's Nebula, visible to the naked eye as the middle star in Orion's sword. Both nebulas and the surrounding gas and dust are among the hottest regions of star formation that can be seen in the night sky. All of these objects have been studied for centuries, yielding insight in modern times into the life cycles of stars. This beautiful vista was created by Australian astrophotographer Terry Hancock. The data were captured in January, February and early March 2014 over eight nights from Hancock's home in Fremont, Michigan. Check out more of his work on his Flickr page. Caption: WIRED Science

I work on images like this for the thrill of discovery. Sure, there are Hubble Space Telescope images of this protoplanetary nebula... but what does it "really" look like using a small (by comparison) ground-based telescope and using full color (broad band) filters? I didn't know, but now I do. :) It is a tiny tiny thing; but it was wonderful to see it develop from the raw data to this rendered result. The central star is very bright and nearly overwhelms the interesting parts of the nebula. In addition to its size, the central star is a big challenge to tame. The overall shape of the nebula is a puzzle for astronomers to figure out. The leading theory suggests that bipolar, cone-shaped, and periodic outflows, when viewed in profile as we do, may give the shape we see. The intense red color still remains a bit of a mystery. Caption: Adam Block

Galactic Club This new Hubble image shows a handful of galaxies in the constellation of Eridanus (The River). NGC 1190, shown here on the right of the frame, stands apart from the rest; it belong to an exclusive club known as Hickson Compact Group 22 (HCG 22). There are four other members of this group, all of which lie out of frame: NGC 1189, NGC 1191, NGC 1192, and NGC 1199. The other galaxies shown here are nearby galaxies 2MASS J03032308-1539079 (centre), and dCAZ94 HCG 22-21 (left), both of which are not part of HCG 22. Hickson Compact Groups are incredibly tightly bound groups of galaxies. Their discoverer Paul Hickson observed only 100 of these objects, which he described in his HCG catalogue in the 1980s. To earn the Hickson Compact Group label, there must be at least four members — each one fairly bright and compact. These short-lived groups are thought to end their lives as giant elliptical galaxies, but despite knowing much about their form and destiny, the role of compact galaxy groups in galactic formation and evolution is still unclear. These groups are interesting partly for their self-destructive tendencies. The group members interact, circling and pulling at one another until they eventually merge together, signalling the death of the group, and the birth of a large galaxy. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Luca Limatola. Image: ESA/Hubble & NASA Acknowledgement: Luca Limatola [high-resolution] Caption: Hubble Heritage Team

Large and small, hundreds of thousands of craters scar the surface of Mars, hollowed out by a multitude of asteroids and comets that impacted the Red Planet throughout its history. This image shows a region of the planet’s northern hemisphere known as Hephaestus Fossae – after the Greek god of fire – that was imaged by the high-resolution stereo camera on ESA’s Mars Express orbiter on 28 December 2007. The image has been coloured to indicate the elevation of the terrain: green and yellow shades represent shallow ground, while blue and purple stand for deep depressions, down to about 4 km. Scattered across the scene are a few dozen impact craters that cover a wide range of sizes, with the largest boasting a diameter of around 20 km. The long and intricate canyon-like features that resemble riverbeds are the phenomenal aftermath of the same fierce impacts that created the largest craters. When a small body such as a comet or an asteroid crashes at high speed into another object in the Solar System, the collision dramatically heats up the surface at the impact site. In the case of the large crater seen in this image, the heat produced by such a powerful smash melted the soil – a mixture of rock, dust and also, hidden deep down, water ice – resulting in a massive overflow that flooded the surrounding environment. Before drying up, this muddy fluid carved a complex pattern of channels while making its way across the planet’s surface. The melted rock–ice mixture also gave rise to the fluidised appearance of the debris blankets surrounding the largest crater. Based on the lack of similar structures near the small craters in this image, scientists believe that only the most powerful impacts – those responsible for forging the largest craters – were able to dig deep enough to release part of the frozen reservoir of water lying beneath the surface. Caption: ESA

The Hubble telescope captured a display of starlight, glowing gas, and silhouetted dark clouds of interstellar dust in this 4-foot-by-8-foot image of the barred spiral galaxy NGC 1300. NGC 1300 is considered to be prototypical of barred spiral galaxies. Barred spirals differ from normal spiral galaxies in that the arms of the galaxy do not spiral all the way into the center, but are connected to the two ends of a straight bar of stars containing the nucleus at its center. At Hubble's resolution, a myriad of fine details, some of which have never before been seen, is seen throughout the galaxy's arms, disk, bulge, and nucleus. Blue and red supergiant stars, star clusters, and star-forming regions are well resolved across the spiral arms, and dust lanes trace out fine structures in the disk and bar. Numerous more distant galaxies are visible in the background, and are seen even through the densest regions of NGC 1300. In the core of the larger spiral structure of NGC 1300, the nucleus shows its own extraordinary and distinct "grand-design" spiral structure that is about 3,300 light-years (1 kiloparsec) long. Only galaxies with large-scale bars appear to have these grand-design inner disks — a spiral within a spiral. Models suggest that the gas in a bar can be funneled inwards, and then spiral into the center through the grand-design disk, where it can potentially fuel a central black hole. NGC 1300 is not known to have an active nucleus, however, indicating either that there is no black hole, or that it is not accreting matter. Caption: Hubble Heritage Team

Lennon Crater Imagine some ejecta It isn't hard to do Terraced walls and impact melt Secondary craters too Imagine central peaks Rising above the floor... You may say I'm a complex crater But I'm not the only one Someday more will join us On the planet closest to the sun. Lennon crater was recently named to honor English musician/singer/songwriter John Lennon (1940-1980). This image was acquired as part of MDIS's high-resolution stereo imaging campaign. Images from the stereo imaging campaign are used in combination with the surface morphology base map or the albedo base map to create high-resolution stereo views of Mercury's surface, with an average resolution of 200 meters/pixel. Viewing the surface under the same Sun illumination conditions but from two or more viewing angles enables information about the small-scale topography of Mercury's surface to be obtained. Image: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington [high-resolution] Caption: Mercury Messenger Team

This image of the debris of an exploded star - known as supernova remnant 1E 0102.2-7219, or "E0102" for short - features data from NASA's Chandra X-ray Observatory. E0102 is located about 190,000 light years away in the Small Magellanic Cloud, one of the nearest galaxies to the Milky Way. It was created when a star that was much more massive than the Sun exploded, an event that would have been visible from the Southern Hemisphere of the Earth over 1000 years ago. Chandra first observed E0102 shortly after its launch in 1999. New X-ray data have now been used to create this spectacular image and help celebrate the ten-year anniversary of Chandra's launch on July 23, 1999. In this latest image of E0102, the lowest-energy X-rays are colored orange, the intermediate range of X-rays is cyan, and the highest-energy X-rays Chandra detected are blue. An optical image from the Hubble Space Telescope (in red, green and blue) shows additional structure in the remnant and also reveals foreground stars in the field. The Chandra image shows the outer blast wave produced by the supernova (blue), and an inner ring of cooler (red-orange) material. This inner ring is probably expanding ejecta from the explosion that is being heated by a shock wave traveling backwards into the ejecta. A massive star (not visible in this image) is illuminating the green cloud of gas and dust to the lower right of the image. This star may have similar properties to the one that exploded to form E0102. Analysis of the Chandra spectrum gives astronomers new information about the geometry of the remnant, with implications for the nature of the explosion. The spectrum - which precisely separates X-rays of different energies - shows some material is moving away from Earth and some is moving toward us. When the material is moving away, its light is shifted toward the red end of the spectrum due to the so-called Doppler effect. Alternatively, when material is moving toward us, the light is bluer because of the same effect. Caption: Chandra Telescope Team

A coronal mass ejection, or CME, is seen on Jan. 14, 2014, erupting away from the sun in this image from the ESA/NASA Solar and Heliospheric Observatory. The sun is obscured to make the dimmer solar atmosphere more visible. The bright image in the top right is Venus. Caption: NASA

Earth and Moon from Mars The HiRISE instrument would make a great backyard telescope for viewing Mars, and we can also use it at Mars to view other planets, such as Jupiter. This is an image of Earth and the Moon, acquired at 5:20 a.m. MST on 3 October 2007, at a range of 142 million kilometers, which gives the HiRISE image a scale of 142 km/pixel and an Earth diameter of about 90 pixels and a Moon diameter of 24 pixels. The phase angle is 98 degrees, which means that less than half of the disks of the Earth and Moon have direct illumination. We could image Earth/Moon at full disk illumination only when they are on the opposite side of the sun from Mars, but then the range would be much greater and the image would show less detail. On the day this image was taken, the Japanese Kayuga (Selene) spacecraft was en route from the Earth to the Moon, and has since returned spectacular images and movies. On the Earth image we can make out the west coast outline of South America at lower right, although the clouds are the dominant features. These clouds are so bright, compared with the Moon, that they are saturated in the HiRISE images. In fact, the RED-filter image was almost completely saturated, the blue-green image had significant saturation, and the brightest clouds were saturated in the IR image. This color image required a fair amount of processing to make a nice-looking release. The Moon image is unsaturated but brightened relative to Earth for this composite. The lunar images are useful for calibration of the camera. Image: NASA/JPL/University of Arizona [high-resolution] Caption: Alfred McEwen and Eric Eliason

One of our closest galactic neighbors shows its awesome beauty in this image from NASA's Spitzer Space Telescope. M33, also known as the Triangulum Galaxy, is a member of what's known as our Local Group of galaxies. Along with our own Milky Way, this group travels together in the universe, as they are gravitationally bound. In fact, M33 is one of the few galaxies that is moving toward the Milky Way despite the fact that space itself is expanding, causing most galaxies in the universe to grow farther and farther apart. When viewed with Spitzer's infrared eyes, this elegant spiral galaxy sparkles with color and detail. Stars appear as glistening blue gems (several of which are actually foreground stars in our own galaxy), while dust rich in organic molecules glows green. The diffuse orange-red glowing areas indicate star-forming regions, while small red flecks outside the spiral disk of M33 are most likely distant background galaxies. But not only is this new image beautiful, it also shows M33 to be surprising large – bigger than its visible-light appearance would suggest. With its ability to detect cold, dark dust, Spitzer can see emission from cooler material well beyond the visible range of M33's disk. Exactly how this cold material moved outward from the galaxy is still a mystery, but winds from giant stars or supernovas may be responsible. M33 is located about 2.9 million light-years away in the constellation Triangulum. This is a three-color composite image showing infrared observations from two of Spitzer instruments. Blue represents combined 3.6- and 4.5-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. Caption: NASA

This wide-field view shows a dark cloud where new stars are forming along with cluster of brilliant stars that have already burst out of their dusty stellar nursery. This cloud is known as Lupus 3 and it lies about 600 light-years from Earth in the constellation of Scorpius (The Scorpion). It is likely that the Sun formed in a similar star formation region more than four billion years ago. This view was created from images forming part of the Digitized Sky Survey 2. Caption: ESO

Titan's Northern Lakes This colorized mosaic from NASA's Cassini mission shows the most complete view yet of Titan's northern land of lakes and seas. Saturn's moon Titan is the only world in our solar system other than Earth that has stable liquid on its surface. The liquid in Titan's lakes and seas is mostly methane and ethane. The data were obtained by Cassini's radar instrument from 2004 to 2013. In this projection, the north pole is at the center. The view extends down to 50 degrees north latitude. In this color scheme, liquids appear blue and black depending on the way the radar bounced off the surface. Land areas appear yellow to white. A haze was added to simulate the Titan atmosphere. Kraken Mare, Titan's largest sea, is the body in black and blue that sprawls from just below and to the right of the north pole down to the bottom right. Ligeia Mare, Titan's second largest sea, is a nearly heart-shaped body to the left and above the north pole. Punga Mare is just below the north pole. The area above and to the left of the north pole is dotted with smaller lakes. Lakes in this area are about 30 miles (50 kilometers) across or less. Most of the bodies of liquid on Titan occur in the northern hemisphere. In fact nearly all the lakes and seas on Titan fall into a box covering about 600 by 1,100 miles (900 by 1,800 kilometers). Only 3 percent of the liquid at Titan falls outside of this area. Scientists are trying to identify the geologic processes that are creating large depressions capable of holding major seas in this limited area. A prime suspect is regional extension of the crust, which on Earth leads to the formation of faults creating alternating basins and roughly parallel mountain ranges. This process has shaped the Basin and Range province of the western United States, and during the period of cooler climate 13,000 years ago much of the present state of Nevada was flooded with Lake Lahontan, which (though smaller) bears a strong resemblance to the region of closely packed seas on Titan. Image: NASA/JPL-Caltech/ASI/USGS [high-resolution] Caption: NASA/JPL

This false color Magellan image shows a portion of Leda Planitia (plains) in the northern hemisphere of Venus, centered at 41 degrees north latitude, 52 degrees east longitude. The area is 220 kilometers (135 miles) wide and 275 kilometers (170 miles) long. This image was produced from Magellan radar data collected in Cycle 2 of the mission. Cycle 2 was completed January 15, 1992. The area was not imaged during the first cycle because of superior conjunction when the sun was between the Earth and Venus, preventing communication with the spacecraft. This image contains examples of several of the major geologic terrains on Venus and illustrates the basic stratigraphy or sequence of geologic events. The oldest terrains appear as bright, highly-fractured or chaotic highlands rising out of the plains. This is seen in the upper left, or northwest, quadrant of the image. The chaotic highlands, sometimes called tessera, may represent older and thicker crustal material and occupy about 15 percent of the surface of Venus. The circular ring structure in the lower left of the image is probably an impact crater. This 40 kilometer (25 miles) diameter crater has been given a proposed name, Heloise, after the French physician who lived from about 1098 to 1164 A.D. The crater was formed by the impact of an asteroid sometime before the plains lavas embayed and covered the region. The plains surround and embay the fractured highland tessera. Plains are formed by fluid volcanic flows that may have once formed vast lava seas which covered all the low lying surfaces. Plains comprise more than 80 percent of the surface of Venus. The most recent activity in the region is volcanism that produced the radar bright flows best seen in the upper right quadrant of the image. Those flows are similar to the darker plains volcanics, but apparently have more rugged surfaces that more efficiently scatter the radar signal back to the spacecraft. Thus the geologic sequence is early fracturing of the tessera, flooding by extensive plains lavas and scattered, less extensive individual flows on the plains surface. Impact cratering occurs throughout geologic history and provides a rough estimate of the time scale. Craters larger than a few kilometers in diameter form on Venus, as they do on Earth, at the rate of about one per million years, with smaller impacts much more frequent than larger ones. The simulated hues are based on color images recorded by the Soviet Venera 13 and 14 spacecraft. Caption: NASA

Bok Globule This view of the dark cloud B68, a so-called Bok globule, is a false-colour composite based on a visible (here rendered as blue), a near-infrared (green) and an infrared (red) image. Since the light from stars behind the cloud is only visible at the longest (infrared) wavelengths, they appear red. Image: ESO [high-resolution] Caption: ESO

This new Hubble image shows a cosmic creepy-crawly known as the Tarantula Nebula in infrared light. This region is full of star clusters, glowing gas, and thick dark dust. Created using observations taken as part of the Hubble Tarantula Treasury Project (HTTP), this image was snapped using Hubble's Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). The Hubble Tarantula Treasury Project (HTTP) is scanning and imaging many of the many millions of stars within the Tarantula, mapping out the locations and properties of the nebula's stellar inhabitants. These observations will help astronomers to piece together an understanding of the nebula's skeleton, viewing its starry structure. Caption: Hubble Heritage Team

Saturn Moon Shadows This close-up view of Saturn's disc captures the transit of several moons across the face of the gas giant planet. The giant orange moon Titan — larger than the planet Mercury — can be seen at upper right. The white icy moons that are much closer to Saturn, hence much closer to the ring plane in this view, are, from left to right: Enceladus, Dione, and Mimas. The dark band running across the face of the planet slightly above the rings is the shadow of the rings cast on the planet. This picture was taken with Hubble's Wide Field Planetary Camera 2 on 24 February 2009, when Saturn was at a distance of roughly 1.25 billion kilometres from Earth. Hubble can see details as small as 300 kilometres across on Saturn. Image: NASA, ESA and the Hubble Heritage Team (STScI/AURA). Acknowledgment: M. Wong (STScI/UC Berkeley) and C. Go (Philippines) [high-resolution] Caption: ESA

The vortex at Saturn's north pole -- seen here in the infrared -- takes on the menacing look of something from the imagination of Edgar Allan Poe. But really, of course, it's just another example of the amazing, mesmerizing meteorology on Saturn. The eye of the immense cyclone is about 2,000 kilometers (1,250 miles) wide, 20 times larger than most on Earth. This view is centered on clouds at 89 degrees north latitude, 109 degrees west longitude. North is up and rotated 33 degrees to the left. The image was taken with the Cassini spacecraft narrow-angle camera on June 14, 2013 using a spectral filter sensitive to wavelengths of near-infrared light centered at 750 nanometers.The view was acquired at a distance of approximately 476,000 miles (766,000 kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 45 degrees. Image scale is 3 miles (5 kilometers) per pixel. Caption: Cassini Solstice Team

Curiosity Wheel The left-front wheel of NASA's Curiosity Mars rover shows dents and holes in this image taken during the 469th Martian day, or sol, of the rover's work on Mars (Nov. 30, 2013). The image was taken by the Mars Hand Lens Imager (MAHLI) camera, which is mounted at the end of Curiosity's robotic arm. By that sol, Curiosity had driven 2.78 miles (4.47 kilometers). An uptick in the pace of wear and tear on the rover's wheels in the preceding few weeks appears to be correlated with driving over rougher terrain than during earlier months of the mission. Routes to future destinations for the mission may be charted to lessen the amount of travel over such rough terrain. Image: NASA/JPL-Caltech/MSSS [high-resolution] Caption: NASA/JPL

The vibrant magentas and blues in this Hubble image of the barred spiral galaxy M83 reveal that the galaxy is ablaze with star formation. The galactic panorama unveils a tapestry of the drama of stellar birth and death. The galaxy, also known as the Southern Pinwheel, lies 15 million light-years away in the constellation Hydra. This image is being used to support a citizen science project titled STAR DATE: M83. The primary goal is to estimate ages for approximately 3,000 star clusters. Amateur scientists will use the presence or absence of the pink hydrogen emission, the sharpness of the individual stars, and the color of the clusters to estimate ages. Participants will measure the sizes of the star clusters and any associated emission nebulae. Finally, the citizen scientists will "explore" the image, identifying a variety of objects ranging from background galaxies to supernova remnants to foreground stars. STAR DATE: M83 is a joint collaborative effort between the Space Telescope Science Institute and Zooniverse, creators of several citizen science projects including Galaxy Zoo, Planet Hunters, and the Andromeda Project (go to www.zooniverse.org to see the full list). The M83 project is scheduled to launch on Monday, January 13, 2014. People interested in exploring this remarkable image in more detail, and in directly participating in a science project, can visit http://www.projectstardate.org. Caption: Hubble Heritage Team

New NEOWISE Sky NASA's NEOWISE spacecraft opened its "eyes" after more than two years of slumber to see the starry sky with the same clarity achieved during its prime mission. This image of a patch of sky in the constellation Pisces is among the first taken by the revived spacecraft's infrared cameras, and shows the ultimate target: asteroids. Appearing as a string of red dots, an asteroid can be seen in a series of exposures captured by the spacecraft. The rocky body belongs to our solar system's main belt, a band of asteroids that orbits between Mars and Jupiter. NEOWISE is on the lookout for both main belt asteroids such as these, and especially for near-Earth objects (NEOs), which include asteroids and comets that pass relatively close to Earth. The asteroid is called Holda, or 872, and was discovered in 1917. The faint red streak in the image is an Earth-orbiting satellite passing above the NEOWISE spacecraft. NEOWISE originated as a mission called WISE, which was put into hibernation in 2011 upon completing its goal of surveying the entire sky in infrared light. WISE cataloged three quarters of a billion objects, including asteroids, stars and galaxies. In August 2013, NASA decided to reinstate the spacecraft on a mission to find and characterize more asteroids. JPL manages NEOWISE for NASA's Science Mission Directorate at the agency's headquarters in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colo., built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. Image: NASA/JPL-Caltech [high-resolution] Caption: NASA/JPL

The sun shines through a truss-based radiator panel and a primary solar array panel on the Earth-orbiting International Space Station (ISS) in this photograph taken by an Expedition 38 crew member on Jan. 2, 2014. The crew on the ISS is awaiting the first commercial resupply mission to the ISS by Orbital Sciences, Orbital-1. Orbital Sciences will proceed with a 1:07 p.m. EST launch attempt of the Orbital-1 cargo resupply mission to the ISS today, Thursday, Jan. 9. Meanwhile, as more than 30 heads of space agencies from around the world gather in Washington Jan. 9-10 for an unprecedented summit on the future of space exploration, the Obama Administration has approved an extension of the ISS until at least 2024. Caption: NASA

Stellar Sneeze Look at the bright star in the middle of this image. Achoo! It has just sneezed. This sight will only last for a few thousand years — a blink of an eye in the young star's life. If you could carry on watching for a few years you would realise it's not just one sneeze, but a sneezing fit. This young star is firing off salvos of super-hot, super-fast gas — Achoo! Achoo! — before it finally exhausts itself. These bursts of gas have shaped the turbulent surroundings, creating structures known as Herbig-Haro objects. These objects are formed from the star's energetic "sneezes". These salvos can contain as much mass as our home planet, and cannon into nearby clouds of gas at hundreds of kilometres per second. Shock waves form, such as the U-shape below this star. Unlike most other astronomical phenomena, as the waves crash outwards, they can be seen moving across human timescales. Soon, this star will stop sneezing, and grow up to be a star like the Sun. This region is actually home to several interesting objects. The star at the centre of the frame is a variable star named V633 Cassiopeiae, with Herbig-Haro objects HH 161 and HH 164 forming parts of the horseshoe-shaped loop emanating from it. The slightly shrouded star just to the left is known as V376 Cassiopeiae, another variable star that has succumbed to its neighbour's infectious sneezing fits; this star is also sneezing, creating yet another Herbig-Haro object — HH 162. Both stars are very young and are still surrounded by dusty material left over from their formation, which spans the gap between the two A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestant Gilles Chapdelaine. Image: ESA/Hubble & NASA Acknowledgement: Gilles Chapdelaine [high-resolution] Caption: Hubble Heritage Team

Recent observations by NASA's Swift spacecraft have provided scientists a unique glimpse into the activity at the center of our galaxy and led to the discovery of a rare celestial entity that may help them test predictions of Albert Einstein's theory of general relativity. The Swift XRT team expects 2014 to be a banner year for the campaign. A cold gas cloud named G2, about three times the mass of Earth, will pass near Sgr A* and already is being affected by tides from the black hole's powerful gravitational field. Astronomers expect G2 will swing so close to the black hole during the second quarter of the year that it will heat up to the point where it produces X-rays.

If some of the cloud's gas actually reaches Sgr A*, astronomers may witness a significant increase in activity from the black hole. The event will unfold over the next few years, giving scientists a front-row seat to study the phenomena. Caption: NASA

Moon Distortion The effects of the small moon Prometheus loom large on two of Saturn's rings in this image taken a short time before Saturn's August 2009 equinox. A long, thin shadow cast by the moon stretches across the A ring on the right. The gravity of potato-shaped Prometheus (86 km, or 53 miles across) periodically creates streamer-channels in the F ring, and the moon's handiwork can seen be on the left of the image. To learn more and to watch a movie of this process, see PIA08397. The novel illumination geometry that accompanies equinox lowers the sun's angle to the ringplane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and cast shadows across the rings. These scenes are possible only during the few months before and after Saturn's equinox, which occurs only once in about 15 Earth years. Before and after equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons, but also the shadows of newly revealed vertical structures in the rings themselves. Prometheus is overexposed in this image. Bright specks in the image are background stars. This view looks toward the northern, unilluminated side of the rings from about 28 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on 30 July 2009. The view was acquired at a distance of approximately 1.8 million km (1.1 million miles) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 97 degrees. Image scale is 10 km (6 miles) per pixel. Image: NASA/JPL [high-resolution] Caption: Cassini Solstice Team

This image of Abell 2744 is the first to come from Hubble's Frontier Fields observing programme, which is using the magnifying power of enormous galaxy clusters to peer deep into the distant Universe. Abell 2744, nicknamed Pandora's Cluster, is thought to have a very violent history, having formed from a cosmic pile-up of multiple galaxy clusters. Abell 2744 is the first of six targets for an observing programme known as Frontier Fields. This three-year, 840-orbit programme will yield our deepest views of the Universe to date, using the power of Hubble to explore more distant regions of space than could otherwise be seen, by observing gravitational lensing effects around six different galaxy clusters. Caption: Hubble Heritage Team

Flickering RS Puppis This festive NASA Hubble Space Telescope image resembles a holiday wreath made of sparkling lights. The bright southern hemisphere star RS Puppis, at the center of the image, is swaddled in a gossamer cocoon of reflective dust illuminated by the glittering star. The super star is ten times more massive than our Sun and 200 times larger. RS Puppis rhythmically brightens and dims over a six-week cycle. It is one of the most luminous in the class of so-called Cepheid variable stars. Its average intrinsic brightness is 15,000 times greater than our Sun's luminosity. The nebula flickers in brightness as pulses of light from the Cepheid propagate outwards. Hubble took a series of photos of light flashes rippling across the nebula in a phenomenon known as a "light echo." Even though light travels through space fast enough to span the gap between Earth and the Moon in a little over a second, the nebula is so large that reflected light can actually be photographed traversing the nebula. By observing the fluctuation of light in RS Puppis itself, as well as recording the faint reflections of light pulses moving across the nebula, astronomers are able to measure these light echoes and pin down a very accurate distance. The distance to RS Puppis has been narrowed down to 6,500 light-years (with a margin of error of only one percent). Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-Hubble/Europe Collaboration Acknowledgment: H. Bond (STScI and Pennsylvania State University) [high-resolution] Caption: Hubble Heritage Team

This image shows the remnant of Supernova 1987A seen in light of very different wavelengths. ALMA data (in red) shows newly formed dust in the centre of the remnant. Hubble (in green) and Chandra (in blue) data show the expanding shock wave. Caption: ESO

Eberswalde Delta This image covers a portion of Eberswalde Crater on Mars, revealing a possible delta-lake transition. Water flowed into the crater through a series of tributary channels to the west of the crater and after the water entered, it formed a distributive network and partly filled the crater to form a lake (Eberswalde Crater is approximately 70 kilometers wide and 1.2 kilometers deep). The bright layers are part of the terminal scarp at the eastern edge of the delta. Some of the steeper slopes visible at the edge of the fan may be coarser-grained resistant channel ridges. The CRISM instrument on board the Mars Reconnaissance Orbiter has detected phyllosilicates (clays) in the bright layers. One of the ways clays form on Earth is when water erodes rock and makes fine particles which settle out of water; this often occurs in river deltas and lake beds. The delta in Eberswalde Crater and the detection of phyllosilicates provides evidence for possible persistent aqueous activity on Mars. Image: NASA/JPL/University of Arizona [high-resolution] Caption: Joannah Metz

The Bubble Nebula (NGC7635) is one of three shells of gas surrounding the massive star BD+602522, the bright star near the center of the bubble. Energetic radiation from the star ionizes the shell, causing it to glow. About six light-years in diameter, the Bubble Nebula is located in the direction of the constellation Cassiopeia. The magenta wisps near the bottom-right of the image are an unexpected bonus—the wisps are the remnants of a supernova that exploded thousands of years ago. This is the first optical image of the supernova remnant, which was discovered at radio wavelengths by the Canadian Galactic Plane Survey in 2005. Caption: NOAO Read NOAO Conditions of Use before downloading

Last Hurrah This image, taken by NASA's Hubble Space Telescope, shows the colorful "last hurrah" of a star like our Sun. The star is ending its life by casting off its outer layers of gas, which formed a cocoon around the star's remaining core. Ultraviolet light from the dying star makes the material glow. The burned-out star, called a white dwarf, is the white dot in the center. Our Sun will eventually burn out and shroud itself with stellar debris, but not for another 5 billion years. Our Milky Way Galaxy is littered with these stellar relics, called planetary nebulae. The objects have nothing to do with planets. Eighteenth- and nineteenth-century astronomers named them planetary nebulae because through small telescopes they resembled the disks of the distant planets Uranus and Neptune. The planetary nebula in this image is called NGC 2440. The white dwarf at the center of NGC 2440 is one of the hottest known, with a surface temperature of nearly 400,000 degrees Fahrenheit (200,000 degrees Celsius). The nebula's chaotic structure suggests that the star shed its mass episodically. During each outburst, the star expelled material in a different direction. This can be seen in the two bow tie-shaped lobes. The nebula also is rich in clouds of dust, some of which form long, dark streaks pointing away from the star. NGC 2440 lies about 4,000 light-years from Earth in the direction of the constellation Puppis. The image was taken Feb. 6, 2007 with Hubble's Wide Field Planetary Camera 2. The colors correspond to material expelled by the star. Blue corresponds to helium; blue-green to oxygen; and red to nitrogen and hydrogen. Image: NASA, ESA, and K. Noll (STScI) [high-resolution] Caption: Hubble Heritage Team

NASA's Hubble Space Telescope gave astronomers their most detailed view yet of a second red spot that emerged on Jupiter in 2006. For the first time in history, astronomers have witnessed the birth of a new red spot on the giant planet, which is located half a billion miles away. The storm is roughly one-half the diameter of its bigger and legendary cousin, the Great Red Spot. Researchers suggest that the new spot may be related to a possible major climate change in Jupiter's atmosphere. Caption: Hubble Heritage Team

Wavelengths of the Sun This still image was taken from a new NASA movie of the sun based on data from NASA's Solar Dynamics Observatory, or SDO, showing the wide range of wavelengths – invisible to the naked eye – that the telescope can view. SDO converts the wavelengths into an image humans can see, and the light is colorized into a rainbow of colors. Yellow light of 5800 Angstroms, for example, generally emanates from material of about 10,000 degrees F (5700 degrees C), which represents the surface of the sun. Extreme ultraviolet light of 94 Angstroms, which is typically colorized in green in SDO images, comes from atoms that are about 11 million degrees F (6,300,000 degrees C) and is a good wavelength for looking at solar flares, which can reach such high temperatures. By examining pictures of the sun in a variety of wavelengths – as is done not only by SDO, but also by NASA's Interface Region Imaging Spectrograph, NASA's Solar Terrestrial Relations Observatory and the European Space Agency/NASA Solar and Heliospheric Observatory -- scientists can track how particles and heat move through the sun's atmosphere. Image: NASA Goddard Space Flight Center [high-resolution] Caption: NASA

Mars Express HRSC (High Resolution Stereo Camera) image of Phobos taken on 9 January 2011 at a distance of 100 km with a resolution of 8.1 m/pixel. Use red-blue glasses to fully appreciate this image. Phobos is approximately 27 × 22 × 18 km and orbits Mars at a distance of 6000 km above the planet’s surface, or 9400 km from the centre of the planet. Caption: ESA

Vesta's Aelia This colorful composite image from NASA's Dawn mission shows the flow of material inside and outside a crater called Aelia on the giant asteroid Vesta. The area is around 14 degrees south latitude. The images that went into this composite were obtained by Dawn's framing camera from September to October 2011. To the naked eye, these structures would not be seen. But here, they stand out in blue and red. The crater has a diameter of 2.7 miles (4.3 kilometers). The exact origin of the flow structures is unknown. A possible explanation is that the impact that produced the crater could have created liquid material with different minerals than the surroundings. The composite image was created by assigning ratios of color information collected from several color filters in visible light and near-infrared light to maximize subtle differences in lithology (the physical characteristics of rock units, such as color, texture and composition). The color scheme pays special attention to the iron-rich mineral pyroxene. Image: NASA/JPL-Caltech/UCLAMPS/DLR/IDA [high-resolution] Caption: NASA/JPL

Chang'e 3 landed on Mare Imbrium (Sea of Rains) just east of a 450 m diameter impact crater on 14 December 2013. Soon after landing, a small rover named Yutu (or Jade Rabbit in English) was deployed and took its first tentative drive onto the airless regolith. At the time of the landing LRO's orbit was far from the landing site so images of the landing were not possible. Ten days later on 24 December, LRO approached the landing site, and LROC was able to acquire a series of six LROC Narrow Angle Camera (NAC) image pairs during the next 36 hours (19 orbits). The highest resolution image was possible when LRO was nearly overhead on 25 December 03:52:49 UT (24 December 22:52:49 EST). At this time LRO was at an altitude of ~150 km above the site, and the pixel size was 150 cm. LROC NAC view of the Chang'e 3 lander (large arrow) and rover (small arrow) just before sunset on their first day of lunar exploration. LROC NAC M1142582775R, image width 576 m, north is up Caption: Mark Robinson

Pulsating Stellar Ghost This NASA/ESA Hubble Space Telescope image shows the planetary nebula NGC 2452, located in the southern constellation of Puppis. The blue haze across the frame is what remains of a star like our Sun after it has depleted all its fuel. When this happens, the core of the star becomes unstable and releases huge numbers of incredibly energetic particles that blow the star's atmosphere away into space. At the centre of this blue cloud lies what remains of the nebula's progenitor star. This cool, dim, and extremely dense star is actually a pulsating white dwarf, meaning that its brightness varies over time as gravity causes waves that pulse throughout the small star's body. A version of this image was entered into the Hubble's Hidden Treasures image processing competition by contestants Luca Limatola and Budeanu Cosmin Mirel. Image: Luca Limatola, Budeanu Cosmin Mirel [high-resolution] Caption: ESA

This image, taken on Dec. 31, 2013 by the AIA instrument on NASA's Solar Dynamics Observatory at 171 Angstrom, shows the current conditions of the quiet corona and upper transition region of the Sun. Caption: NASA

Pickering's Triangle A wide-field image of Pickering's Triangle taken with the National Science Foundation's Mayall 4-meter telescope at Kitt Peak National Observatory. Pickering's Triangle is part of the Cygnus Loop supernova remnant, which includes the famous Veil Nebula. It is located about 1,500 light-years from Earth, in the constellation Cygnus, the Swan. Astronomers estimate that the supernova explosion that produced the nebula occurred between 5,000 to 10,000 years ago; the entire shell stretches more than six full Moons in width across the sky. This image was obtained in September 2007 by Travis Rector and Heidi Schweiker by combining two full pointings of the 64-megapixel NOAO Mosaic-1 imager mounted on the National Science Foundation's historic Mayall 4-meter telescope. Image: T.A. Rector/University of Alaska Anchorage, H. Schweiker/WIYN and NOAO/AURA/NSF [high-resolution] Read NOAO Conditions of Use before downloading Caption: NOAO

The Heart and Soul nebulae are seen in this infrared mosaic from NASA’s Wide-field Infrared Survey Explorer, or WISE. The image covers an area of the sky over ten times as wide as the full moon, and eight times as high (5.5 x 3.9 degrees), in the constellation Cassiopeia. Located about 6,000 light-years from Earth, the Heart and Soul nebulae form a vast star-forming complex that makes up part of the Perseus spiral arm of our Milky Way Galaxy. The nebula to the right is the Heart, designated IC 1805 and named after its resemblance to a human heart. To the left is the Soul nebula, also known as the Embryo nebula, IC 1848, or W5. The Perseus arm lies further from the center of the Milky Way than the arm that contains our Sun. The Heart and Soul nebulae stretch out nearly 580 light-years across, covering a small portion of the diameter of the Milky Way, which is roughly 100,000 light-years across. The two nebulae are both massive star-making factories, marked by giant bubbles that were blown into surrounding dust by radiation and winds from the stars. WISE's infrared vision allows it to see into the cooler and dustier crevices of clouds like these, where gas and dust are just beginning to collect into new stars. These stars are less than a few million of years old -- youngsters in comparison to stars like the sun, which is nearly 5 billion years old. Also visible near the bottom of this image are two galaxies, Maffei 1 and Maffei 2. Both galaxies contain billions of stars and, at about 10 million light-years away, are well outside our Milky Way yet relatively close compared to most galaxies. Maffei 1 is the bluish elliptical object and Maffei 2 is the spiral galaxy. All four infrared detectors aboard WISE were used to make this image. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust. Caption: WISE Team

Flight Over Triton This simulated voyage over the surface of Neptune's large moon Triton was produced using topographic maps derived from images acquired by NASA's Voyager spacecraft during its August 1989 flyby. Triton was the last solid object visited by the Voyager 2 spacecraft on its epic 10-year tour of the outer solar system. Voyager mapped only the hemisphere that faces Neptune, but revealed a very young surface scarred by rising blobs of ice (diapirs), faults, and volcanic pits and lava flows composed of water and other ices. The video begins near the western edge of this hemisphere with an approach over cantaloupe terrain and two large smooth walled plains. The video tracks due east for roughly 1500 kilometers over a large province of volcanic pits, calderas and smooth plains. As can be seen in this video, Triton is locally very rugged (with pits and mounds that are typically a few hundred meters [several hundred feet] high), but has no large mountains or deep basins and regional relief is low. The lack of large topographic features is a consequence of Triton's high internal heat and the low strength of most ices. The video was produced by using a new topographic map of Triton, combined with a 1.65-kilometer resolution image mosaic. Topographic mapping was based on shape-from-shading analysis of the original Voyager images. Vertical relief has been exaggerated by a factor of 25 to aid interpretation. The raw data from which this product was developed were retrieved from the Planetary Data System's data archives. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Voyager spacecraft and its two onboard cameras were designed, developed and assembled at JPL. This video was processed by Paul Schenk (http://www.lpi.usra.edu/lpi/schenk/) at the Lunar and Planetary Institute. Image: NASA/JPL/Universities Space Research Association/Lunar & Planetary Institute [high-resolution] Caption: NASA/JPL

Smoky Rings in Space The hazy and aptly named Fine Ring Nebula, shown here, is an unusual planetary nebula. Planetary nebulae form when some dying stars, having expanded into a red giant phase, expel a shell of gas as they evolve into white dwarfs. Most planetary nebulae are either spherical or elliptical in shape, or bipolar (featuring two symmetric lobes of material). But the Fine Ring Nebula — captured here by the ESO Faint Object Spectrograph and Camera mounted on the New Technology Telescope at the La Silla Observatory in Chile — looks like an almost perfect circular ring. Astronomers believe that some of these more unusually shaped planetary nebulae are formed when the progenitor star is actually a binary system. The interaction between the primary star and its orbiting companion shapes the ejected material. The stellar object at the centre of the Fine Ring Nebula is indeed thought to be a binary system, orbiting with a period of 2.9 days. Observations suggest that the binary pair is almost perfectly face-on from our vantage point, implying that the planetary nebula’s structure is aligned in the same way. We are looking down on a torus (doughnut shape) of ejected material, leading to the strikingly circular ring shape in the image. Planetary nebulae are shaped by the complex interplay of many physical processes. Not only can these celestial objects be admired for their beauty, but the study of precisely how they form their striking shapes is a fascinating topic in astronomical research. This image was made using multiple filters: light observed through B and O-III filters is shown in blue, V is shown in green, R is shown in orange, and H-alpha in red. The image is approximately 200 arcseconds across. Image: ESO [high-resolution] Caption: ESO

Crab Nebula Chemicals This image shows a composite view of the Crab Nebula, an iconic supernova remnant in our Galaxy, as viewed by ESA's Herschel Space Observatory and the NASA/ESA Hubble Space Telescope.

A wispy and filamentary cloud of gas and dust, the Crab Nebula is the remnant of a supernova explosion that was observed by Chinese astronomers in the year 1054. The image combines Hubble's view of the nebula at visible wavelengths, which was obtained using three different filters sensitive to the emission from oxygen and sulphur ions and is shown here in blue, with Herschel's far-infrared image, which reveals the emission from dust in the nebula and is shown here in red.

While studying the dust content of the Crab Nebula with Herschel, a team of astronomers have detected emission lines from argon hydride (ArH+), a molecular ion containing the noble gas argon. This is the first detection of a noble-gas based compound in space.

A comparison of the Herschel data with observations of the Crab Nebula performed at other wavelengths revealed that the regions where they had found ArH+ also exhibit higher concentrations of ions of argon (Ar+) and hydrogen molecules (H2). There, Ar+ can react with H2 forming argon hydride and atomic hydrogen.

The Herschel image is based on data taken with the PACS instrument at a wavelength of 70 microns; the Hubble image is based on archival data from the Wide Field and Planetary Camera 2 (WFPC2). Image: ESA/Herschel/PACS/MESS Key Programme Supernova Remnant Team; NASA, ESA and Allison Loll/Jeff Hester (Arizona State University) [high-resolution] Caption: ESA

Super Sun Images The region located between the surface of the sun and its atmosphere has been revealed as a more violent place than previously understood, according to images and data from NASA's newest solar observatory, the Interface Region Imaging Spectrograph, or IRIS. Solar observatories look at the sun in layers. By capturing light emitted by atoms of different temperatures, they can focus in on different heights above the sun's surface extending well out into the solar atmosphere, the corona. On June 27, 2013, IRIS, was launched, to study what's known as the interface region – a layer between the sun's surface and corona that previously was not well observed.

Over its first six months, IRIS has thrilled scientists with detailed images of the interface region, finding even more turbulence and complexity than expected. IRIS scientists presented the mission's early observations at a press conference at the Fall American Geophysical Union meeting on Dec. 9, 2013. Image: NASA/LMSAL/IRIS [high-resolution] Caption: NASA Goddard Spaceflight Center

Earth and Moon from Juno This cosmic pirouette of Earth and our moon was captured by the Juno spacecraft as it flew by Earth on Oct. 9, 2013. Video: NASA/JPL [high-resolution] Caption: NASA/JPL

Dark Stellar Nursery Illuminated by the light of nearby stars, the nebula M-78 exhibits a ghostly appearance in this 10-minute exposure taken with a 6" refractor at the Siding Spring Observatory in Australia. Located in the constellation of Orion -- some1,600 light years from Earth -- this reflection nebula is known to contain more than 40 very young stars still in the process of formation. Image: NASA/MSFC/MEO/Bill Cooke [high-resolution] Caption: NASA

Reaching for the Stars A small, dense object only twelve miles in diameter is responsible for this beautiful X-ray nebula that spans 150 light years. At the center of this image made by NASA's Chandra X-ray Observatory is a very young and powerful pulsar, known as PSR B1509-58, or B1509 for short. The pulsar is a rapidly spinning neutron star which is spewing energy out into the space around it to create complex and intriguing structures, including one that resembles a large cosmic hand. In this image, the lowest energy X-rays that Chandra detects are colored red, the medium range is green, and the most energetic ones are blue. Astronomers think that B1509 is about 1700 years old as measured in Earth's time-frame (referring to when events are observable at Earth) and is located about 17,000 light years away. Neutron stars are created when massive stars run out of fuel and collapse. B1509 is spinning completely around almost 7 times every second and is releasing energy into its environment at a prodigious rate - presumably because it has an intense magnetic field at its surface, estimated to be 15 trillion times stronger than the Earth's magnetic field. The combination of rapid rotation and ultra-strong magnetic field makes B1509 one of the most powerful electromagnetic generators in the Galaxy. This generator drives an energetic wind of electrons and ions away from the neutron star. As the electrons move through the magnetized nebula, they radiate away their energy and create the elaborate nebula seen by Chandra. In the innermost regions, a faint circle surrounds the pulsar, and marks the spot where the wind is rapidly decelerated by the slowly expanding nebula. In this way, B1509 shares some striking similarities to the famous Crab Nebula. However B1509's nebula is 15 times wider than the Crab's diameter of 10 light years. Finger-like structures extend to the north, apparently energizing knots of material in a neighboring gas cloud known as RCW 89. The transfer of energy from the wind to these knots makes them glow brightly in X-rays (orange and red features to the upper right). The temperature in this region appears to vary in a circular pattern around this ring of emission, suggesting that the pulsar may be precessing like a spinning top and sweeping an energizing beam around the gas in RCW 89. Image: NASA/CXC/SAO/P.Slane, et al. [high-resolution] Caption: Chandra telescope team

Spiky Nebula With the cloudy weather views of the Universe have been hampered this past week. Here is a recently completed image of a colorful nebula that was captured before the winter weather arrived. Most interesting are some of the spiky appendages of the inner nebula. These are likely bi-polar outflows from newly formed stars embedded within the clouds. (You will need to see the largest image by clicking on the thumbnail to see this detail.) This field's vibrant color and complicated structures require a moment of viewing to fully appreciate. Image: Adam Block/Mount Lemmon SkyCenter/University of Arizona [high-resolution] Caption: Adam Block

Saturn in Shadows The shadows of Saturn's rings cast onto the planet appear as a thin band at the equator in this image taken as the planet approached its August 2009 equinox. The novel illumination geometry that accompanies equinox lowers the sun's angle to the ringplane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and to cast shadows across the rings. These scenes are possible only during the few months before and after Saturn's equinox which occurs only once in about 15 Earth years. Before and after equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons, but also the shadows of newly revealed vertical structures in the rings themselves. The planet's southern hemisphere can be seen through the transparent D ring in the lower right of the image. The rings have been brightened by a factor of 9.5 relative to the planet to enhance visibility. This view looks toward the northern, unilluminated side of the rings from about 30 degrees above the ringplane. Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft wide-angle camera on July 18, 2009 at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn. Image scale is 122 kilometers (76 miles) per pixel. Image: NASA/JPL/Space Science Institute [high-resolution] Caption: NASA/JPL

Curiosity's 100,000th Shot Since landing on Mars in August 2012, NASA's Curiosity Mars rover has fired the laser on its Chemistry and Camera (ChemCam) instrument more than 100,000 times at rock and soil targets up to about 23 feet (7 meters) away. This mosaic of images from ChemCam's remote micro-imager camera show the rock, called "Ithaca," that received the 100,000th zapping, and 299 others. The scale bar at upper right is 1 centimeter (0.4 inch). The target was 13 feet, 3 inches (4.04 meters) from the top of Curiosity's mast, where the laser and remote micro-imager are mounted, when the rock was inspected during the 439th Martian day, or sol, of the rover's work on Mars (Oct. 30, 2013). The image shows scars from the 10 laser-targeted points labeled from point 1 to point 10. Each observation point received 30 laser shots. One of the 30 shots at point 1 was the 100,000th firing of the ChemCam laser. The vertical line of 10 points examined by ChemCam on Ithaca starts in a pitted lower coarser grained layer and crosses into a finer grained, smoother, upper layer. The chemical composition of the two layers appears to be very similar. Image: NASA/JPL-Caltech/LANL/CNES/IRAP/UNM [high-resolution] Caption: NASA/JPL

Youngest X-ray Binary The youngest member of an important class of objects called X-ray binaries has been found using data from Chandra (blue) and the Australia Compact Telescope Array (purple). X-ray binaries consist of a dense object -- either a black hole or a neutron star -- in orbit with a star like the Sun. Researchers found that the neutron star in Circinus X-1 is less than 4,600 years old, making the X-ray binary much younger than any other known in the Milky Way. This discovery allows astronomers to study a critical phase after a supernova explosion and the birth of a neutron star. Image: X-ray: NASA/CXC/Univ. of Wisconsin-Madison/S.Heinz et al; Optical: DSS; Radio: CSIRO/ATNF/ATCA [high-resolution] Caption: Chandra Telescope Team

Titan and Vortex The sunlit edge of Titan's south polar vortex stands out distinctly against the darkness of the moon's unilluminated hazy atmosphere. The Cassini spacecraft images of the vortex led scientists to conclude that its clouds form at a much higher altitude -- where sunlight can still reach -- than the surrounding haze. Titan (3,200 miles, or 5,150 kilometers across) is Saturn's largest moon. This view looks toward the trailing hemisphere of Titan. North on Titan is up and rotated 32 degrees to the left. The image was taken with the Cassini spacecraft narrow-angle camera on July 14, 2013 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers.

The view was obtained at a distance of approximately 808,000 miles (1.3 million kilometers) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 82 degrees. Image scale is 5 miles (8 kilometers) per pixel. Image: NASA/JPL-Caltech/Space Science Institute [high-resolution] Caption: NASA

Polar Ring Galaxy This new Hubble image shows a peculiar galaxy known as NGC 660, located around 45 million light-years away from us. NGC 660 is classified as a "polar ring galaxy", meaning that it has a belt of gas and stars around its centre that it ripped from a near neighbour during a clash about one billion years ago. The first polar ring galaxy was observed in 1978 and only around a dozen more have been discovered since then, making them something of a cosmic rarity. Unfortunately, NGC 660’s polar ring cannot be seen in this image, but has plenty of other features that make it of interest to astronomers – its central bulge is strangely off-kilter and, perhaps more intriguingly, it is thought to harbour exceptionally large amounts of dark matter. In addition, in late 2012 astronomers observed a massive outburst emanating from NGC 660 that was around ten times as bright as a supernova explosion. This burst was thought to be caused by a massive jet shooting out of the supermassive black hole at the centre of the galaxy. Image: ESA/Hubble & NASA [high-resolution] Caption: Hubble Heritage Team

Jupiter from Mars The HiRISE camera is the most powerful telescope to have left Earth orbit. As such, it is capable of some interesting astronomical observations. This image of Jupiter and its major satellites was acquired to calibrate the pointing and color response of the camera. An oversight in planning this unusual observation put the focus mechanism in the wrong location, blurring the image. This does not detract from the calibration objectives, but makes the raw image less aesthetic. To compensate, the image has been "sharpened" on the ground by Dennis Gallagher, the HiRISE chief optical designer. With this sharpening, and because Mars is closer to Jupiter than Earth is, this image has comparable resolution as the Hubble Space Telescope's pictures of Jupiter. The colors are not what is seen by the human eye because HiRISE is able to detect light with a slightly longer wavelength than we can (that is, the infrared). While there is no standard observation geometry, this image was acquired on 11 January 2007, 2102 spacecraft event time to be precise. Image: NASA/JPL/University of Arizona [high-resolution] Caption: Laszlo Kestay

Colorful Eagle Nebula This wide-field image of the Eagle Nebula was taken at the National Science Foundation's 0.9-meter telescope on Kitt Peak with the NOAO Mosaic CCD camera. Located in the constellation of Serpens, the Serpent, the Eagle Nebula is a very luminous open cluster of stars surrounded by dust and gas. The three pillars at the center of the image, made famous in an image by the Hubble Space Telescope, are being sculpted by the intense radiation from the hot stars in the cluster. This image was created by combining emission-line images in Hydrogen-alpha (green), Oxygen [O III] (blue) and Sulfur [S II] (red). Image: T.A.Rector (NRAO/AUI/NSF and NOAO/AURA/NSF) and B.A.Wolpa (NOAO/AURA/NSF) [high-resolution] Read NOAO Conditions of Use before downloading Caption: NOAO

Wispy Irregular Galaxy This sprinkling of cosmic glitter makes up the galaxy known as ESO 149-3, located some 20 million light-years away from us. It is an example of an irregular galaxy, characterised by its amorphous, undefined shape — a property that sets it apart from its perhaps more photogenic spiral and elliptical relatives. Around one quarter of all galaxies are thought to be irregular-type galaxies. In this image taken with the NASA/ESA Hubble Space Telescope ESO 149-3 can be seen as a smattering of golden and blue stars, with no apparent central nucleus or arm structure. The surrounding sky is rich in other more distant galaxies, visible as small, colourful streaks and dashes. A version of this image was submitted to the Hubble's Hidden Treasures image processing competition by contestant Luca Limatola. Image: ESA/Hubble & NASA Acknowledgement: Luca Limatola [high-resolution] Caption: Hubble Heritage Team

ISON's Big Day In the early hours of Nov. 27, 2013, Comet ISON entered the field of view of the European Space Agency/NASA Solar and Heliospheric Observatory. In this picture, called a coronagraph, the bright light of the sun itself is blocked so the structures around it are visible. The comet is seen in the lower right; a giant cloud of solar material, called a coronal mass ejection or CME, is seen billowing out under the sun. Comet ISON, which began its trip from the Oort cloud region of our solar system, will reach its closest approach to the sun on Thanksgiving Day, skimming just 730,000 miles above the sun's surface.

NASA is tracking Comet ISON's journey and hosting events to discuss what the public worldwide may see as the comet traverses the sun. For the latest news and information, visit www.nasa.gov/ison. Image: ESA/NASA/SOHO [high-resolution] Caption: NASA

Filaments of Death The Large Magellanic Cloud is one of the closest galaxies to our own. Astronomers have now used the power of the ESO’s Very Large Telescope to explore NGC 2035, one of its lesser known regions, in great detail. This new image shows clouds of gas and dust where hot new stars are being born and are sculpting their surroundings into odd shapes. But the image also shows the effects of stellar death — filaments created by a supernova explosion (left). Image: ESO [high-resolution] Caption: ESO

Mach 1000 Shockwave When a star explodes as a supernova, it shines brightly for a few weeks or months before fading away. Yet the material blasted outward from the explosion still glows hundreds or thousands of years later, forming a picturesque supernova remnant. What powers such long-lived brilliance? In the case of Tycho's supernova remnant, astronomers have discovered that a reverse shock wave racing inward at Mach 1000 (1000 times the speed of sound) is heating the remnant and causing it to emit X-ray light. "We wouldn't be able to study ancient supernova remnants without a reverse shock to light them up," says Hiroya Yamaguchi, who conducted this research at the Harvard-Smithsonian Center for Astrophysics (CfA). Tycho's supernova was witnessed by astronomer Tycho Brahe in 1572. The appearance of this "new star" stunned those who thought the heavens were constant and unchanging. At its brightest, the supernova rivaled Venus before fading from sight a year later. Modern astronomers know that the event Tycho and others observed was a Type Ia supernova, caused by the explosion of a white dwarf star. The explosion spewed elements like silicon and iron into space at speeds of more than 11 million miles per hour (5,000 km/s). When that ejecta rammed into surrounding interstellar gas, it created a shock wave - the equivalent of a cosmic "sonic boom." That shock wave continues to move outward today at about Mach 300. The interaction also created a violent "backwash" - a reverse shock wave that speeds inward at Mach 1000. "It's like the wave of brake lights that marches up a line of traffic after a fender-bender on a busy highway," explains CfA co-author Randall Smith. The reverse shock wave heats gases inside the supernova remnant and causes them to fluoresce. The process is similar to what lights household fluorescent bulbs, except that the supernova remnant glows in X-rays rather than visible light. The reverse shock wave is what allows us to see supernova remnants and study them, hundreds of years after the supernova occurred. "Thanks to the reverse shock, Tycho's supernova keeps on giving," says Smith. The team studied the X-ray spectrum of Tycho's supernova remnant with the Suzaku spacecraft. They found that electrons crossing the reverse shock wave are rapidly heated by a still-uncertain process. Their observations represent the first clear evidence for such efficient, "collisionless" electron heating at the reverse shock of Tycho's supernova remnant. The team plans to look for evidence of similar reverse shock waves in other young supernova remnants. These results have been accepted for publication in The Astrophysical Journal. Image: X-ray: NASA/CXC/Rutgers/K. Eriksen et al.; Optical (starry background): DSS [high-resolution] Caption: Harvard-Smithsonian CfA

Anemic Spiral Galaxy How far away is spiral galaxy NGC 4921? Although presently estimated to be about 310 million light years distant, a more precise determination could be coupled with its known recession speed to help humanity better calibrate the expansion rate of the entire visible universe. Toward this goal, several images were taken by the Hubble Space Telescope in order to help identify key stellar distance markers known as Cepheid variable stars. Since NGC 4921 is a member of the Coma Cluster of Galaxies, refining its distance would also allow a better distance determination to one of the largest nearby clusters in the local universe. The magnifi