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Showing posts from October, 2017

Pumpkin Sun

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Active regions on the Sun combined to look something like a jack-o-lantern’s face on October 8, 2014. The image was captured by NASA's Solar Dynamics Observatory, or SDO, which watches the Sun at all times from its orbit in space. The active regions in this image appear brighter because those are areas that emit more light and energy. They are markers of an intense and complex set of magnetic fields hovering in the Sun’s atmosphere, the corona. This image blends together two sets of extreme ultraviolet wavelengths at 171 and 193 Ã…ngströms, typically colorized in gold and yellow, to create a particularly Halloween-like appearance. Image Credit: NASA/SDO Explanation from: https://www.nasa.gov/content/goddard/sdo-jack-o-lantern-sun

IC 2118: the Witch Head Nebula

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As the name implies, this reflection nebula associated with the star Rigel looks suspiciously like a fairytale crone. Formally known as IC 2118 in the constellation Orion, the Witch Head Nebula glows primarily by light reflected from the star. The color of this very blue nebula is caused not only by blue color of its star, but also because the dust grains reflect blue light more efficiently than red. A similar physical process causes Earth's daytime sky to appear blue. Image Credit: NASA/STScI Digitized Sky Survey/Noel Carboni Explanation from: https://www.nasa.gov/multimedia/imagegallery/image_feature_1209.html

VdB 152: A Ghost in Cepheus

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Described as a "dusty curtain" or "ghostly apparition," mysterious reflection nebula VdB 152 really is very faint. Far from your neighborhood on this Halloween Night, the cosmic phantom is nearly 1,400 light-years away. Also catalogued as Ced 201, it lies along the northern Milky Way in the royal constellation Cepheus. Near the edge of a large molecular cloud, pockets of interstellar dust in the region block light from background stars or scatter light from the embedded bright star giving parts of the nebula a characteristic blue color. Ultraviolet light from the star is also thought to cause a dim reddish luminescence in the nebular dust. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud's velocity. This deep telescopic image of the region spans about 7 light-years. Image Credit: Stephen Leshin Explanation from: https://www.nasa.gov/...

Fornax Galaxy Cluster

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Countless galaxies vie for attention in this monster image of the Fornax Galaxy Cluster, some appearing only as pinpricks of light while others dominate the foreground. One of these is the lenticular galaxy NGC 1316. The turbulent past of this much-studied galaxy has left it with a delicate structure of loops, arcs and rings that astronomers have now imaged in greater detail than ever before with the VLT Survey Telescope. This astonishingly deep image also reveals a myriad of dim objects along with faint intracluster light. Captured using the exceptional sky-surveying abilities of the VLT Survey Telescope (VST) at ESO’s Paranal Observatory in Chile, this deep view reveals the secrets of the luminous members of the Fornax Cluster, one of the richest and closest galaxy clusters to the Milky Way. This 2.3-gigapixel image is one of the largest images ever released by ESO. Perhaps the most fascinating member of the cluster is NGC 1316, a galaxy that has experienced a dynamic history, being ...

Milky Way Galaxy seen over Auxiliary Telescope

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Brilliant blue stars litter the southern sky and the galactic bulge of our home galaxy, the Milky Way, hangs serenely above the horizon in this spectacular shot of ESO’s Paranal Observatory. This image was taken atop Cerro Paranal in Chile, home to ESO’s Very Large Telescope (VLT). In the foreground, the open dome of one of the four 1.8-metre Auxiliary Telescopes can be seen. The four Auxiliary Telescopes can be utilised together, to form the Very Large Telescope Interferometer (VLTI). The plane of the Milky Way is dotted with bright regions of hot gas. The very bright star towards the upper left corner of the frame is Antares — the brightest star in Scorpius and the fifteenth brightest star in the night sky. Image Credit: ESO/B. Tafreshi Explanation from: https://www.eso.org/public/images/potw1744a/

Saturn seen by Cassini spacecraft

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Stunning views like this image of Saturn's night side are only possible thanks to our robotic emissaries like Cassini. Until future missions are sent to Saturn, Cassini's image-rich legacy must suffice. Because Earth is closer to the Sun than Saturn, observers on Earth only see Saturn's day side. With spacecraft, we can capture views (and data) that are simply not possible from Earth, even with the largest telescopes. This view looks toward the sunlit side of the rings from about 7 degrees above the ring plane. The image was taken in visible light with the wide-angle camera on NASA's Cassini spacecraft on June 7, 2017. The view was obtained at a distance of approximately 751,000 miles (1.21 million kilometers) from Saturn. Image scale is 45 miles (72 kilometers) per pixel. The Cassini spacecraft ended its mission on September 15, 2017. Image Credit: NASA/JPL-Caltech/Space Science Institute Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21350

The Moon seen by Galileo spacecraft

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During its flight, the Galileo spacecraft returned images of the Moon. The Galileo spacecraft surveyed the Moon on December 7, 1992, on its way to explore the Jupiter system in 1995-1997. The left part of this north pole view is visible from Earth. This color picture is a mosaic assembled from 18 images taken by Galileo's imaging system through a green filter. The left part of this picture shows the dark, lava-filled Mare Imbrium (upper left); Mare Serenitatis (middle left), Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 650-kilometer (400-mile) impact structure partly filled with dark volcanic deposits, is seen at the center of the image. The Moon's north pole is located just inside the shadow zone, about a third of the way from the top left of the illuminated region. Image Credit: ...

Galaxy Cluster WHL J24.3324-8.477

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This NASA/ESA Hubble Space Telescope image is chock-full of galaxies — each glowing speck is a different galaxy, bar the bright flash in the middle of the image which is actually a star lying within our own galaxy that just happened to be in the way. At the centre of the image lies something especially interesting, the centre of the massive galaxy cluster called WHL J24.3324-8.477, including the brightest galaxy of the cluster. The Universe contains structures on various scales — planets collect around stars, stars collect into galaxies, galaxies collect into groups, and galaxy groups collect into clusters. Galaxy clusters contain hundreds to thousands of galaxies bound together by gravity. Dark matter and dark energy play key roles in the formation and evolution of these clusters, so studying massive galaxy clusters can help scientists to unravel the mysteries of these elusive phenomena. This infrared image was taken by Hubble’s Advanced Camera for Surveys and Wide-Field Camera 3 as p...

Jupiter, Io and Europa seen by Juno spacecraft

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This color-enhanced image of Jupiter and two of its largest moons -- Io and Europa -- was captured by NASA's Juno spacecraft as it performed its eighth flyby of the gas giant planet. The image was taken on Sept. 1, 2017 at 3:14 p.m. PDT (6:14 p.m. EDT). At the time the image was taken, the spacecraft was about 17,098 miles (27,516 kilometers) from the tops of the clouds of the planet at a latitude of minus 49.372 degrees. Closer to the planet, the Galilean moon of Io can be seen at an altitude of 298,880 miles (481,000 kilometers) and at a spatial scale of 201 miles (324 kilometers) per pixel. In the distance (to the left), another one of Jupiter's Galilean moons, Europa, is visible at an altitude of 453,601 miles (730,000 kilometers) and at a spatial scale of 305 miles (492 kilometers) per pixel. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21968

Search for Habitable Worlds

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New NASA research is helping to refine our understanding of candidate planets beyond our Solar System that might support life. “Using a model that more realistically simulates atmospheric conditions, we discovered a new process that controls the habitability of exoplanets and will guide us in identifying candidates for further study,” said Yuka Fujii of NASA’s Goddard Institute for Space Studies (GISS), New York, New York and the Earth-Life Science Institute at the Tokyo Institute of Technology, Japan. Previous models simulated atmospheric conditions along one dimension, the vertical. Like some other recent habitability studies, the new research used a model that calculates conditions in all three dimensions, allowing the team to simulate the circulation of the atmosphere and the special features of that circulation, which one-dimensional models cannot do. The new work will help astronomers allocate scarce observing time to the most promising candidates for habitability. Liquid water ...

Elliptical Galaxy NGC 4993

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The elliptical galaxy NGC 4993 is located about 130 million light-years from Earth. On 17 August 2017 the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometer both detected gravitational waves from the collision of two neutron stars within this galaxy. The event also resulted in a flare of light, called a kilonova, which is visible to the upper left of the galactic centre in this image from the NASA/ESA Hubble Space Telescope. Image Credit: NASA and ESA Explanation from: https://www.spacetelescope.org/images/heic1717c/

Fomalhaut Debris Disk

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Fomalhaut is one of the brightest stars in the sky. At roughly 25 light-years away the star lies especially close to us, and can be seen shining brightly in the constellation of Piscis Austrinus (The Southern Fish). This image from the Atacama Large Millimeter/submillimeter Array (ALMA) shows Fomalhaut (centre) encircled by a ring of dusty debris — this is the first time this scene has been captured at such high resolution and sensitivity at millimetre wavelengths. Fomalhaut’s disc comprises a mix of cosmic dust and gas from comets in the Fomalhaut system (exocomets), released as the exocomets graze past and smash into one another. This turbulent environment resembles an early period in our own Solar System known as the Late Heavy Bombardment, which occurred approximately four billions years ago. This era saw huge numbers of rocky objects hurtle into the inner Solar System and collide with the young terrestrial planets, including Earth, where they formed a myriad of impact craters — ma...

An Atmosphere Around the Moon?

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Looking up at the Moon at night, Earth’s closest neighbor appears in shades of gray and white; a dry desert in the vacuum of space, inactive and dead for billions of years. Like many things, though, with the Moon, there is so much more than what meets the eye. Research completed by NASA Marshall Space Flight Center planetary volcanologist Debra Needham in Huntsville, Alabama, and planetary scientist David Kring at the Lunar and Planetary Institute in Houston, Texas, suggests that billions of years ago, the Moon actually had an atmosphere. The ancient lunar atmosphere was thicker than the atmosphere of Mars today and was likely capable of weathering rocks and producing windstorms. Perhaps most importantly, it could be a source for some, if not all, of the water detected on the Moon. “It just completely changes the way we think of the Moon,” said Needham, a scientist in Marshall’s Science and Technology Office. “It becomes a much more dynamic planetary body to explore.” A time sequence ...

When Neutron Stars Collide

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This illustration shows the hot, dense, expanding cloud of debris stripped from two neutron stars just before they collided. Within this neutron-rich debris, large quantities of some of the universe's heaviest elements were forged, including hundreds of Earth masses of gold and platinum. This represents the first time scientists detected light tied to a gravitational-wave event, thanks to two merging neutron stars in the galaxy NGC 4993, located about 130 million light-years from Earth in the constellation Hydra. Image Credit: NASA Goddard Space Flight Center/CI Lab Explanation from: https://www.nasa.gov/image-feature/when-neutron-stars-collide

Colliding Galaxies Arp 243

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This image, captured by the NASA/ESA Hubble Space Telescope, shows what happens when two galaxies become one. The twisted cosmic knot seen here is NGC 2623 — or Arp 243 — and is located about 250 million light-years away in the constellation of Cancer (The Crab). NGC 2623 gained its unusual and distinctive shape as the result of a major collision and subsequent merger between two separate galaxies. This violent encounter caused clouds of gas within the two galaxies to become compressed and stirred up, in turn triggering a sharp spike of star formation. This active star formation is marked by speckled patches of bright blue; these can be seen clustered both in the centre and along the trails of dust and gas forming NGC 2623’s sweeping curves (known as tidal tails). These tails extend for roughly 50 000 light-years from end to end. Many young, hot, newborn stars form in bright stellar clusters — at least 170 such clusters are known to exist within NGC 2623. NGC 2623 is in a late stage of...

Hubble observes source of gravitational waves for the first time

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The NASA/ESA Hubble Space Telescope has observed for the first time the source of a gravitational wave, created by the merger of two neutron stars. This merger created a kilonova — an object predicted by theory decades ago — that ejects heavy elements such as gold and platinum into space. This event also provides the strongest evidence yet that short duration gamma-ray bursts are caused by mergers of neutron stars. This discovery is the first glimpse of multi-messenger astronomy, bringing together both gravitational waves and electromagnetic radiation. On 17 August 2017 the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo Interferometer both alerted astronomical observers all over the globe about the detection of a gravitational wave event named GW170817. About two seconds after the detection of the gravitational wave, ESA’s INTEGRAL telescope and NASA’s Fermi Gamma-ray Space Telescope observed a short gamma-ray burst in the same direction. In the night followin...

Puerto Rico seen from the International Space Station

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NASA astronaut Joe Acaba photographed Puerto Rico from the cupola of the International Space Station on October 12, 2017. Acaba, whose parents were both born in Puerto Rico, joined NASA as a member of the 2004 class of astronauts and is on his third mission to the space station as a Flight Engineer on the Expedition 53/54 crew. Image Credit: NASA

Protoplanetary Disk V1247 Orionis

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This image from the Atacama Large Millimeter/submillimeter Array (ALMA) shows V1247 Orionis, a young, hot star surrounded by a dynamic ring of gas and dust, known as a circumstellar disc. This disc can be seen here in two parts: a clearly defined central ring of matter and a more delicate crescent structure located further out. The region between the ring and crescent, visible as a dark strip, is thought to be caused by a young planet carving its way through the disc. As the planet orbits around its parent star, its motion creates areas of high pressure on either side of its path, similar to how a ship creates bow waves as it cuts through water. These areas of high pressure could become protective barriers around sites of planet formation; dust particles are trapped within them for millions of years, allowing them the time and space to clump together and grow. The exquisite resolution of ALMA allows astronomers to study the intricate structure of such a dust trapping vortex for the fir...

ESO Telescopes Observe First Light from Gravitational Wave Source - Merging neutron stars scatter gold and platinum into space

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This artist’s impression shows two tiny but very dense neutron stars at the point at which they merge and explode as a kilonova. Such a very rare event is expected to produce both gravitational waves and a short gamma-ray burst, both of which were observed on 17 August 2017 by LIGO–Virgo and Fermi/INTEGRAL respectively. Subsequent detailed observations with many ESO telescopes confirmed that this object, seen in the galaxy NGC 4993 about 130 million light-years from the Earth, is indeed a kilonova. Such objects are the main source of very heavy chemical elements, such as gold and platinum, in the Universe. ESO’s fleet of telescopes in Chile have detected the first visible counterpart to a gravitational wave source. These historic observations suggest that this unique object is the result of the merger of two neutron stars. The cataclysmic aftermaths of this kind of merger — long-predicted events called kilonovae — disperse heavy elements such as gold and platinum throughout the Univers...

VIMOS image of galaxy NGC 4993 showing the visible-light counterpart to a merging neutron star pair

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This image from the VIMOS instrument on ESO’s Very Large Telescope at the Paranal Observatory in Chile shows the galaxy NGC 4993, about 130 million light-years from Earth. The galaxy is not itself unusual, but it contains something never before witnessed, the aftermath of the explosion of a pair of merging neutron stars, a rare event called a kilonova (seen just above and slightly to the left of the centre of the galaxy). This merger also produced gravitational waves and gamma rays, both of which were detected by LIGO-Virgo and Fermi/INTEGRAL respectively. Image Credit: ESO/A.J. Levan, N.R. Tanvir Explanation from: https://www.eso.org/public/images/eso1733b/

VLT/MUSE image of the galaxy NGC 4993 and associated kilonova

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This image from the MUSE instrument on ESO’s Very Large Telescope at the Paranal Observatory in Chile shows the galaxy NGC 4993, about 130 million light-years from Earth. The galaxy is not itself unusual, but it contains something never before witnessed, the aftermath of the explosion of a pair of merging neutron stars, a rare event called a kilonova (seen just above and slightly to the left of the centre of the galaxy). This merger also produced gravitational waves and gamma rays, both of which were detected by LIGO-Virgo and Fermi/INTEGRAL respectively. By also creating a spectrum for each part of the object MUSE allows the emission from glowing gas to be seen, which appears in red here and reveals a surprising spiral structure. Image Credit: ESO/J.D. Lyman, A.J. Levan, N.R. Tanvir Explanation from: https://www.eso.org/public/images/eso1733d/

GROND image of kilonova in NGC 4993

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Image obtained by ESO's Gamma-ray Burst Optical/Near-infrared Detector (GROND) attached to the MPG/ESO 2.2-metre telescope at La Silla Observatory. Image Credit: ESO/S. Smartt & T.-W. Chen

VST image of kilonova in NGC 4993

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This image from the VST telescope at ESO's Paranal Observatory in Chile shows the galaxy NGC 4993, about 130 million light-years from Earth. The galaxy is not itself unusual, but it contains something never before witnessed, the aftermath of the explosion of a pair of merging neutron stars, a rare event called a kilonova (seen just above and slightly to the left of the centre of the galaxy). This merger also produced gravitational waves and gamma rays, both of which were detected by LIGO-Virgo and Fermi/INTEGRAL respectively. Image Credit: ESO/A. Grado Explanation from: https://www.eso.org/public/images/eso1733m/

The sky around the galaxy NGC 4993

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This wide-field image generated from the Digitized Sky Survey 2 shows the sky around the galaxy NGC 4993. This galaxy was the host to a merger between two neutron stars, which led to a gravitational wave detection, a short gamma-ray burst and an optical identification of a kilonova event. Image Credit: ESO and Digitized Sky Survey 2 Explanation from: https://www.eso.org/public/images/eso1733i/

Smoke from California wildfires seen by Sentinel-3A satellite

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The Copernicus Sentinel-3A satellite captured this image of smoke from wildfires in the US state of California on 9 October 2017. Wildfires broke out in parts of the state on 8 October 2017 around Napa Valley, and the smoke was spread by strong northeasterly winds. Image Credit: ESA

Supernova Remnant G292.0+1.8

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At a distance of about 20,000 light years, G292.0+1.8 is one of only three supernova remnants in the Milky Way known to contain large amounts of oxygen. These oxygen-rich supernovas are of great interest to astronomers because they are one of the primary sources of the heavy elements (that is, everything other than hydrogen and helium) necessary to form planets and people. The X-ray image from Chandra shows a rapidly expanding, intricately structured, debris field that contains, along with oxygen (yellow and orange), other elements such as magnesium (green) and silicon and sulfur (blue) that were forged in the star before it exploded. Image Credit: NASA/CXC/SAO Explanation from: https://www.nasa.gov/chandra/multimedia/chandra-15th-anniversary-g292.html

Dual Supermassive Black Holes

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This illustration depicts two centrally located supermassive black holes surrounded by disks of hot gas. The black holes orbit each other for hundreds of millions of years before they merge to form a single supermassive black hole that sends out intense gravitational waves. Five new pairs of merging supermassive black holes have been discovered by combining data from different telescopes. Models predict such growing dual supermassive black holes, but relatively few have been found. Researchers used Chandra observations to follow up on promising candidate mergers identified in optical and infrared studies. X-ray and infrared radiation is able to penetrate obscuring clouds of gas and dust that keep these black hole pairs otherwise hidden. This graphic shows two of five new pairs of supermassive black holes recently identified by astronomers using a combination of data from NASA's Chandra X-ray Observatory, the Wide-Field Infrared Survey Explorer (WISE), the ground-based Large Binocul...

Emission Nebula NGC 6357

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This image, captured by ESO’s Very Large Telescope (VLT) at Paranal, shows a small part of the well-known emission nebula, NGC 6357, located some 8000 light-years away, in the tail of the southern constellation of Scorpius (The Scorpion). The image glows with the characteristic red of an H II region, and contains a large amount of ionised and excited hydrogen gas. The cloud is bathed in intense ultraviolet radiation — mainly from the open star cluster Pismis 24, home to some massive, young, blue stars — which it re-emits as visible light, in this distinctive red hue. The cluster itself is out of the field of view of this picture, its diffuse light seen illuminating the cloud on the centre-right of the image. We are looking at a close-up of the surrounding nebula, showing a mesh of gas, dark dust, and newly born and still forming stars. Image Credit: ESO Explanation from: https://www.eso.org/public/images/potw1334a/

Dwarf Galaxy ESO 553-46

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As far as galaxies are concerned, size can be deceptive. Some of the largest galaxies in the Universe are dormant, while some dwarf galaxies, such as ESO 553-46 imaged here by the NASA/ESA Hubble Space Telescope, can produce stars at a hair-raising rate. In fact, ESO 553-46 has one of the highest rates of star formation of the 1000 or so galaxies nearest to the Milky Way. No mean feat for such a diminutive galaxy! Clusters of young, hot stars are speckling the galaxy, burning with a fierce blue glow. The intense radiation they produce also causes surrounding gas to light up, which is bright red in this image. The small mass and distinctive colouring of galaxies of this type prompted astronomers to classify them, appropriately, as blue compact dwarfs (BCD). Lacking the clear core and structure that many larger galaxies — such as the Milky Way — have, BCDs such as ESO 553-46 are composed of many large clusters of stars bound together by gravity. Their chemical makeup is interesting to as...

Dusty Ring around Boyajians Star

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This illustration depicts a hypothetical uneven ring of dust orbitingKIC 8462852, also known as Boyajians Star or Tabby's Star. Astronomers have found the dimming of the star over long periods appears to be weaker at longer infrared wavelengths of light and stronger at shorter ultraviolet wavelengths. Such reddening is characteristic of dust particles and inconsistent with more fanciful alien megastructure concepts, which would evenly dim all wavelengths of light. By studying observations from NASAsSpitzer and Swift telescopes, as well as the Belgian AstroLAB IRIS observatory, the researchers have been able to better constrain the size of the dust particles. This places them within the range found in dust disks orbiting stars, and larger than the particles typically found in interstellar dust. The system is portrayed with a couple of comets, consistent with previous studies that have found evidence for cometary activity within the system. Image Credit: NASA/JPL-Caltech/R. Hurt (IPA...

4LGSF on UT4 of the VLT at ESO's Paranal Observatory

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The 4 Laser Guide Star Facility (4LGSF), a new subsystem of the Adaptive Optics Facility (AOF) on UT4 of the Very Large Telescope (VLT), at ESO's Paranal Observatory in Chile. The facility saw first light in April 2016 and is the most powerful laser guide star system in the world. The image was taken by ESO Photo Ambassador Juan Carlos Muñoz-Mateos. Image Credit: Juan Carlos Muñoz-Mateos/ESO Explanation from: https://www.eso.org/public/images/ut4_4lasers-cc/

Large Magellanic Cloud Galaxy in the Infrared

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This vibrant image from NASA's Spitzer Space Telescope shows the Large Magellanic Cloud, a satellite galaxy to our own Milky Way galaxy. The infrared image, a mosaic of 300,000 individual tiles, offers astronomers a unique chance to study the lifecycle of stars and dust in a single galaxy. Nearly one million objects are revealed for the first time in this Spitzer view, which represents about a 1,000-fold improvement in sensitivity over previous space-based missions. Most of the new objects are dusty stars of various ages populating the Large Magellanic Cloud; the rest are thought to be background galaxies. The blue color in the picture, seen most prominently in the central bar, represents starlight from older stars. The chaotic, bright regions outside this bar are filled with hot, massive stars buried in thick blankets of dust. The red color around these bright regions is from dust heated by stars, while the red dots scattered throughout the picture are either dusty, old stars or m...

Jupiter seen by NASA's Juno spacecraft

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This striking image of Jupiter was captured by NASA's Juno spacecraft as it performed its eighth flyby of the gas giant planet. The image was taken on September 1, 2017 at 2:58 p.m. PDT (5:58 p.m. EDT). At the time the image was taken, the spacecraft was 4,707 miles (7,576 kilometers) from the tops of the clouds of the planet at a latitude of about -17.4 degrees. Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21966

Aurora over Canada seen from the International Space Station

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The spectacular aurora borealis, or the “northern lights,” over Canada is sighted from the International Space Station near the highest point of its orbital path. The station’s main solar arrays are seen in the left foreground. This photograph was taken by a member of the Expedition 53 crew aboard the station on September 15, 2017. Image Credit: NASA Explanation from: https://www.nasa.gov/image-feature/northern-lights-over-canada-0

Comet C/2017 K2 (PANSTARRS)

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This Hubble Space Telescope image shows a fuzzy cloud of dust, called a coma, surrounding the comet C/2017 K2 PANSTARRS (K2), the farthest active comet ever observed entering the solar system. Hubble snapped images of K2 when the frozen visitor was over 2.4 billion kilometres from the Sun, just beyond Saturn's orbit. Even at that remote distance, sunlight is warming the frigid comet, producing a 128,000-kilometre-wide coma that envelops a tiny, solid nucleus. K2 has been traveling for millions of years from its home in the Oort Cloud, a spherical region at the edge of our solar system. This frigid area contains hundreds of billions of comets, the icy leftovers from the formation of the solar system 4.6 billion years ago. The image was taken in June 2017 by Hubble's Wide Field Camera 3. Image Credit: NASA, ESA, and D. Jewitt (UCLA) Explanation from: https://www.spacetelescope.org/images/opo1740a/

Spiral Galaxy NGC 6753

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Despite the advances made in past decades, the process of galaxy formation remains an open question in astronomy. Various theories have been suggested, but since galaxies come in all shapes and sizes — including elliptical, spiral, and irregular — no single theory has so far been able to satisfactorily explain the origins of all the galaxies we see throughout the Universe. To determine which formation model is correct (if any), astronomers hunt for the telltale signs of various physical processes. One example of this is galactic coronas, which are huge, invisible regions of hot gas that surround a galaxy’s visible bulk, forming a spheroidal shape. They are so hot that they can be detected by their X-ray emission, far beyond the optical radius of the galaxy. Because they are so wispy, these coronas are extremely difficult to detect. In 2013, astronomers highlighted NGC 6753, imaged here by the NASA/ESA Hubble Space Telescope, as one of only two known spiral galaxies that were both massi...

Tungurahua Volcano Eruption

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Tungurahua, Ecuador Image Credit: Sebastián Crespo

Spiral Galaxy NGC 1964

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This spectacular spiral galaxy, known as NGC 1964, resides approximately 70 million light-years away in the constellation of Lepus (The Hare). NGC 1964 has a bright and dense core. This core sits within a mottled oval disc, which is itself encircled by distinct spiral arms speckled with bright starry regions. The brilliant centre of the galaxy caught the eye of the astronomer William Herschel on the night of 20 November 1784, leading to the galaxy’s discovery and subsequent documentation in the New General Catalogue. In addition to containing stars, NGC 1964 lives in a star-sprinkled section of the sky. In this view from the Wide Field Imager (WFI) — an instrument mounted on the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory, Chile — the star HD 36785 can be seen to the galaxy’s immediate right. Above it reside two other prominent stars named HD 36784 and TYC 5928-368-1 — and the large bright star below NGC 1964 is known as BD-22 1147. This view of NGC 1964 also contains an ...

Star-Forming Regions in the Large Magellanic Cloud Galaxy

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At a distance of just 160 000 light-years, the Large Magellanic Cloud (LMC) is one of the Milky Way’s closest companions. It is also home to one of the largest and most intense regions of active star formation known to exist anywhere in our galactic neighbourhood — the Tarantula Nebula. This NASA/ESA Hubble Space Telescope image shows both the spindly, spidery filaments of gas that inspired the region’s name, and the intriguing structure of stacked “bubbles” that forms the so-called Honeycomb Nebula (to the lower left). The Honeycomb Nebula was found serendipitously by astronomers using ESO’s New Technology Telescope to image the nearby SN1987A, the closest observed supernova to Earth for over 400 years. The nebula’s strange bubble-like shape has baffled astronomers since its discovery in the early 1990s. Various theories have been proposed to explain its unique structure, some more exotic than others. In 2010, a group of astronomers studied the nebula and, using advanced data analysis...

Tungurahua Volcano Eruption

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Tungurahua, Ecuador Image Credit: Per-Andre Hoffmann

Spiral Galaxy NGC 4490

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This oddly-shaped galactic spectacle is bursting with brand new stars. The pink fireworks in this image taken with the NASA/ESA Hubble Space Telescope are regions of intense star formation, triggered by a cosmic-scale collision. The huge galaxy in this image, NGC 4490, has a smaller galaxy in its gravitational grip and is feeling the strain. Compared to the other fundamental forces in the Universe, gravity is fairly weak. Despite this, gravity has an influence over huge distances and is the driving force behind the motions of the most massive objects in the cosmos. The scattered and warped appearance of the galaxy in this image, NGC 4490, is a prime example of the results of gravity’s unrelenting tug. Over millions of years, the mutual gravitational attraction between NGC 4490 and its smaller neighbour, NGC 4485, has dragged the two galaxies closer. Eventually, they collided in a swirling crush of stars, gas, and dust. In this image, this most intense period is already over and the two...