July 15, 2017

Grand Canyon seen from the International Space Station

Grand Canyon seen from the International Space Station

On April 3, 2017, the student-controlled EarthKAM camera aboard the International Space Station captured this photograph of a favorite target -- the Grand Canyon -- from low Earth orbit. The camera has been aboard the orbiting outpost since the first space station expedition began in November 2000 and supports approximately four missions annually.

The Sally Ride Earth Knowledge Acquired by Middle School Students (Sally Ride EarthKAM) program provides a unique educational opportunity for thousands of students multiple times a year. EarthKAM is an international award-winning education program, allowing students to photograph and analyze our planet from the perspective of the International Space Station. Using the Internet, students control a special digital camera on the orbiting laboratory to photograph Earth's coastlines, mountain ranges and other interesting geographical topography.

Image Credit: Sally Ride EarthKAM
Explanation from: https://www.nasa.gov/image-feature/space-stations-earthkam-sees-the-grand-canyon/

Elliptical Galaxy NGC 2768

Elliptical Galaxy NGC 2768

Like a lighthouse in the fog the luminous core of NGC 2768 slowly fades outwards to a dull white haze in this image taken by the NASA/ESA Hubble Space Telescope.

NGC 2768 is an elliptical galaxy in the constellation of Ursa Major (The Great Bear). It is a huge bundle of stars, dominated by a bright central region, where a supermassive black hole feasts on a constant stream of gas and dust being fed to it by its galactic host.

The galaxy is also marked by a prominent plume of dust reaching out from the centre and lying perpendicular to the galaxy’s plane. This dust conceals a symmetrical, s-shaped pair of jets that are being produced by the supermassive black hole as it feeds.

Image Credit: ESA/Hubble, NASA and S. Smartt (Queen's University Belfast)
Explanation from: https://www.spacetelescope.org/images/potw1548a/

LL Pegasi

LL Pegasi

This image is a composite of images made with the NASA/ESA Hubble Space Telescope and the Atacama Large Millimeter/submillimeter Array (ALMA), both observing the binary star system LL Pegasi. The old star LL Pegasi is continuously losing gaseous material as it evolves into a planetary nebula, and the distinct spiral shape is the imprint made by the stars orbiting in this gas.

Image Credit: ALMA (ESO/NAOJ/NRAO)/H. Kim et al., ESA/NASA & R. Sahai
Explanation from: https://www.eso.org/public/images/potw1710b/

Puyehue-Cordón Caulle Volcano Eruption

Puyehue-Cordón Caulle Volcano Eruption 

Osorno, Los Lagos, Chile
June 5, 2011

Image Credit: Ivan Alvarado

Evolution of a Supernova

Evolution of a Supernova

These illustrations show the progression of a supernova blast. A massive star (left), which has created elements as heavy as iron in its interior, blows up in a tremendous explosion (middle), scattering its outer layers in a structure called a supernova remnant (right). The supernova explosion itself also creates many elements, including those heavier than iron, such as gold. New observations from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, are filling in the missing pieces in the puzzle of how massive stars explode.

Image Credit: NASA/CXC/SAO/JPL-Caltech
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA17844

Galaxy Cluster Abell 2744

Galaxy Cluster Abell 2744

This is a NASA/ESA Hubble Space Telescope image of the galaxy cluster Abell 2744. Shown in blue on the image is a map of the dark matter found within the cluster. This cluster was part of a study of 72 galaxy cluster collisions which determined that dark matter interacts with other dark matter even less than previously thought.

Image Credit: NASA, ESA, D. Harvey

July 14, 2017

Cumulonimbus Cloud seen from the International Space Station

Cumulonimbus Cloud seen from the International Space Station

The cauliflower-like formations above the flat part of this cumulonimbus cloud represent overshooting cloud tops. Overshooting tops occur when forces push the clouds up through the troposphere, the lowest region of the atmosphere, and into the stratosphere. The warm central Pacific Ocean sea surface during the 2015-2016 El Niño lofted abnormal amounts of cloud ice and water vapor into the stratosphere, creating conditions similar to those that could occur on a larger scale in a warming world.

Image Credit: NASA/ESA
Explanation from: https://www.nasa.gov/feature/langley/2015-2016-el-ni-o-provided-natural-experiment-on-the-effects-of-warming-seas

Cassiopeia A

Cassiopeia A

The mystery of how Cassiopeia A exploded is unraveling thanks to new data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. In this image, NuSTAR data, which show high-energy X-rays from radioactive material, are colored blue. Lower-energy X-rays from non-radioactive material, imaged previously with NASA's Chandra X-ray Observatory, are shown in red, yellow and green.

The new view shows a more complete picture of Cassiopeia A, the remains of a star that blew up in a supernova event whose light reached Earth about 350 years ago, when it could have appeared to observers as a star that suddenly brightened. The remnant is located 11,000 light-years away from Earth.

NuSTAR is the first telescope capable of taking detailed pictures of the radioactive material in the Cassiopeia A supernova remnant. While other telescopes have detected radioactivity in these objects before, NuSTAR is the first capable of pinpointing the location of the radioactivity, creating maps. When massive star explode, they create many elements: non-radioactive ones like iron and calcium found in your blood and bones; and radioactive elements like titanium-44, the decay of which sends out high-energy X-ray light that NuSTAR can see.

By mapping titanium-44 in Cassiopeia A, astronomers get a direct look at what happened in the core of the star when it was blasted to smithereens. These NuSTAR data complement previous observations made by Chandra, which show elements, such as iron, that were heated by shock waves farther out from the remnant's center.

In this image, the red, yellow and green data were collected by Chandra at energies ranging from 1 to 7 kiloelectron volts (keV). The red color shows heated iron, and green represents heated silicon and magnesium. The yellow is what astronomers call continuum emission, and represents a range of X-ray energies.

The titanium-44, shown in blue, was detected by NuSTAR at energies ranging between 68 and 78 keV.

The NuSTAR observations point to a possible solution to the puzzle of how stars detonate. The fact that the titanium -- which is a direct tracer of the supernova blast -- is concentrated in clumps at the core supports a theory referred to as "mild asymmetries." In this scenario, material sloshes about at the heart of the supernova, reinvigorating a shock wave and allowing it to blow out the star's outer layers.

Image Credit: NASA/JPL-Caltech/CXC/SAO
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA17838

Spiral Galaxy NGC 2500

Spiral Galaxy NGC 2500

Discovered by British astronomer William Herschel over 200 years ago, NGC 2500 lies about 30 million light-years away in the northern constellation of Lynx. As this NASA/ESA Hubble Space Telescope image shows, NGC 2500 is a particular kind of spiral galaxy known as a barred spiral, its wispy arms swirling out from a bright, elongated core.

Barred spirals are actually more common than was once thought. Around two-thirds of all spiral galaxies — including the Milky Way — exhibit these straight bars cutting through their centres. These cosmic structures act as glowing nurseries for newborn stars, and funnel material towards the active core of a galaxy. NGC 2500 is still actively forming new stars, although this process appears to be occurring very unevenly. The upper half of the galaxy — where the spiral arms are slightly better defined — hosts many more star-forming regions than the lower half, as indicated by the bright, dotted islands of light.

There is another similarity between NGC 2500 and our home galaxy. Together with Andromeda, Triangulum, and many smaller natural satellites, the Milky Way is part of the Local Group of galaxies, a gathering of over 50 galaxies all loosely held together by gravity. NGC 2500 forms a similar group with some of its nearby neighbours, including NGC 2541, NGC 2552, NGC 2537, and the bright, Andromeda-like spiral NGC 2481 (known collectively as the NGC 2841 group).

Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1728a/

July 13, 2017

Turquoise Swirls in the Black Sea

Turquoise Swirls in the Black Sea

Most summers, jewel-toned hues appear in the Black Sea. The turquoise swirls are not the brushstrokes of a painting; they indicate the presence of phytoplankton, which trace the flow of water currents and eddies.

On May 29, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured the data for this image of an ongoing phytoplankton bloom in the Black Sea. The image is a mosaic, composed from multiple satellite passes over the region.

Phytoplankton are floating, microscopic organisms that make their own food from sunlight and dissolved nutrients. Here, ample water flow from rivers like the Danube and Dnieper carries nutrients to the Black Sea. In general, phytoplankton support fish, shellfish, and other marine organisms. But large, frequent blooms can lead to eutrophication—the loss of oxygen from the water—and end up suffocating marine life.

One type of phytoplankton commonly found in the Black Sea are coccolithophores—microscopic plankton that are plated with white calcium carbonate. When aggregated in large numbers, these reflective plates are easily visible from space as bright, milky water.

“The May ramp-up in reflectivity in the Black Sea, with peak brightness in June, seems consistent with results from other years,” said Norman Kuring, an ocean scientist at NASA’s Goddard Space Flight Center. Although Kuring does not study this region, the bloom this year is one of the brightest to catch his eye since 2012.

Other types of phytoplankton can look much different in satellite imagery. “It’s important to remember that not all phytoplankton blooms make the water brighter,” Kuring said. “Diatoms, which also bloom in the Black Sea, tend to darken water more than they brighten it.”

Image Credit: Norman Kuring, NASA’s Ocean Biology Processing Group
Explanation from: https://earthobservatory.nasa.gov/IOTD/view.php?id=90318

Jupiter's Great Red Spot

Jupiter's Great Red Spot

This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Gerald Eichstädt using data from the JunoCam imager on NASA's Juno spacecraft.

The image is approximately illumination adjusted and strongly enhanced to draw viewers' eyes to the iconic storm and the turbulence around it.

The image was taken on July 10, 2017 at 07:07 p.m. PDT (10:07 p.m. EDT), as the Juno spacecraft performed its 7th close flyby of Jupiter. At the time the image was taken, the spacecraft was about 6,130 miles (9,866 kilometers) from the tops of the clouds of the planet.

Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21773

New Lone Sunspot Group

New Lone Sunspot Group

A prominence at the edge of the Sun provided us with a splendid view of solar plasma as it churned and streamed over less than one day (June 25-26, 2017). The charged particles of plasma were being manipulated by strong magnetic forces. When viewed in this wavelength of extreme ultraviolet light, we can trace the movements of the particles. Such occurrences are fairly common but much easier to see when they are near the Sun's edge. For a sense of scale, the arch of prominence in the still image has risen up several times the size of Earth.

Image Credit: NASA/GSFC/Solar Dynamics Observatory
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21783

July 12, 2017

Massive Iceberg Breaks Off from Antarctica

Massive Iceberg Breaks Off from Antarctica
Snapshot of the rift in the Larsen C on November 10, 2016

An iceberg about the size of the state of Delaware split off from Antarctica’s Larsen C ice shelf sometime between July 10 and July 12. The calving of the massive new iceberg was captured by the Moderate Resolution Imaging Spectroradiometer on NASA’s Aqua satellite, and confirmed by the Visible Infrared Imaging Radiometer Suite instrument on the joint NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite. The final breakage was first reported by Project Midas, an Antarctic research project based in the United Kingdom.

Larsen C, a floating platform of glacial ice on the east side of the Antarctic Peninsula, is the fourth largest ice shelf ringing Earth’s southernmost continent. In 2014, a crack that had been slowly growing into the ice shelf for decades suddenly started to spread northwards, creating the nascent iceberg. Now that the close to 2,240 square-mile (5,800 square kilometers) chunk of ice has broken away, the Larsen C shelf area has shrunk by approximately 10 percent.

“The interesting thing is what happens next, how the remaining ice shelf responds,” said Kelly Brunt, a glaciologist with NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland in College Park. “Will the ice shelf weaken? Or possibly collapse, like its neighbors Larsen A and B? Will the glaciers behind the ice shelf accelerate and have a direct contribution to sea level rise? Or is this just a normal calving event?”

Ice shelves fringe 75 percent of the Antarctic ice sheet. One way to assess the health of ice sheets is to look at their balance: when an ice sheet is in balance, the ice gained through snowfall equals the ice lost through melting and iceberg calving. Even relatively large calving events, where tabular ice chunks the size of Manhattan or bigger calve from the seaward front of the shelf, can be considered normal if the ice sheet is in overall balance. But sometimes ice sheets destabilize, either through the loss of a particularly big iceberg or through disintegration of an ice shelf, such as that of the Larsen A Ice Shelf in 1995 and the Larsen B Ice Shelf in 2002. When floating ice shelves disintegrate, they reduce the resistance to glacial flow and thus allow the grounded glaciers they were buttressing to significantly dump more ice into the ocean, raising sea levels.

Scientists have monitored the progression of the rift throughout the last year was using data from the European Space Agency Sentinel-1 satellites and thermal imagery from NASA’s Landsat 8 spacecraft. Over the next months and years, researchers will monitor the response of Larsen C, and the glaciers that flow into it, through the use of satellite imagery, airborne surveys, automated geophysical instruments and associated field work.

In the case of this rift, scientists were worried about the possible loss of a pinning point that helped keep Larsen C stable. In a shallow part of the sea floor underneath the ice shelf, a bedrock protrusion, named the Bawden Ice Rise, has served as an anchor point for the floating shelf for many decades. Ultimately, the rift stopped short of separating from the protrusion.

“The remaining 90 percent of the ice shelf continues to be held in place by two pinning points: the Bawden Ice Rise to the north of the rift and the Gipps Ice Rise to the south,” said Chris Shuman, a glaciologist with Goddard and the University of Maryland at Baltimore County. “So I just don’ see any near-term signs that this calving event is going to lead to the collapse of the Larsen C ice shelf. But we will be watching closely for signs of further changes across the area.”

The first available images of Larsen C are airborne photographs from the 1960s and an image from a US satellite captured in 1963. The rift that has produced the new iceberg was already identifiable in those pictures, along with a dozen other fractures. The crack remained dormant for decades, stuck in a section of the ice shelf called a suture zone, an area where glaciers flowing into the ice shelf come together. Suture zones are complex and more heterogeneous than the rest of the ice shelf, containing ice with different properties and mechanical strengths, and therefore play an important role in controlling the rate at which rifts grow. In 2014, however, this particular crack started to rapidly grow and traverse the suture zones, leaving scientists perplexed.

“We don’t currently know what changed in 2014 that allowed this rift to push through the suture zone and propagate into the main body of the ice shelf,” said Dan McGrath, a glaciologist at Colorado State University who has been studying the Larsen C ice shelf since 2008.

McGrath said the growth of the crack, given our current understanding, is not directly linked to climate change.

“The Antarctic Peninsula has been one of the fastest warming places on the planet throughout the latter half of the 20th century. This warming has driven really profound environmental changes, including the collapse of Larsen A and B,” McGrath said. “But with the rift on Larsen C, we haven’t made a direct connection with the warming climate. Still, there are definitely mechanisms by which this rift could be linked to climate change, most notably through warmer ocean waters eating away at the base of the shelf.”

While the crack was growing, scientists had a hard time predicting when the nascent iceberg would break away. It’s difficult because there are not enough measurements available on either the forces acting on the rift or the composition of the ice shelf. Further, other poorly observed external factors, such as temperatures, winds, waves and ocean currents, might play an important role in rift growth. Still, this event has provided an important opportunity for researchers to study how ice shelves fracture, with important implications for other ice shelves.

The U.S. National Ice Center will monitor the trajectory of the new iceberg, which is likely to be named A-68. The currents around Antarctica generally dictate the path that the icebergs follow. In this case, the new berg is likely to follow a similar path to the icebergs produced by the collapse of Larsen B: north along the coast of the Peninsula, then northeast into the South Atlantic.

“It’s very unlikely it will cause any trouble for navigation,” Brunt said.

Image Credit: NASA/John Sonntag
Explanation from: https://www.nasa.gov/feature/goddard/2017/massive-iceberg-breaks-off-from-antarctica

NASA's SDO Watches a Sunspot Turn Toward Earth

NASA's SDO Watches a Sunspot Turn Toward Earth

An active region on the Sun — an area of intense and complex magnetic fields — has rotated into view on the Sun and seems to be growing rather quickly in this video captured by NASA’s Solar Dynamics Observatory between July 5-11, 2017. Such sunspots are a common occurrence on the Sun, but are less frequent as we head toward solar minimum, which is the period of low solar activity during its regular approximately 11-year cycle. This sunspot is the first to appear after the Sun was spotless for two days, and it is the only sunspot group at this moment. Like freckles on the face of the Sun, they appear to be small features, but size is relative: The dark core of this sunspot is actually larger than Earth.

Image Credit: NASA’s Goddard Space Flight Center/SDO/Joy Ng, producer
Explanation from: https://www.nasa.gov/feature/goddard/2017/nasas-sdo-watches-a-sunspot-turn-toward-earth

Molecular Cloud W51

Molecular Cloud W51

  • Giant molecular clouds, containing mostly hydrogen and helium, are where most new stars and planets form.
  • W51 is one of the closest such objects to Earth so it is an excellent target for learning more about the star-formation process.
  • A new composite image of W51 with X-ray data from Chandra (blue) and Spitzer (orange and yellow-green) is being released.
  • The X-ray data show the young stars are often clumped together in clusters, while bathing their surroundings in high-energy light.

In the context of space, the term 'cloud' can mean something rather different from the fluffy white collections of water in the sky or a way to store data or process information. Giant molecular clouds are vast cosmic objects, composed primarily of hydrogen molecules and helium atoms, where new stars and planets are born. These clouds can contain more mass than a million suns, and stretch across hundreds of light years.

The giant molecular cloud known as W51 is one of the closest to Earth at a distance of about 17,000 light years. Because of its relative proximity, W51 provides astronomers with an excellent opportunity to study how stars are forming in our Milky Way galaxy.

A new composite image of W51 shows the high-energy output from this stellar nursery, where X-rays from Chandra are colored blue. In about 20 hours of Chandra exposure time, over 600 young stars were detected as point-like X-ray sources, and diffuse X-ray emission from interstellar gas with a temperature of a million degrees or more was also observed. Infrared light observed with NASA's Spitzer Space Telescope appears orange and yellow-green and shows cool gas and stars surrounded by disks of cool material.

W51 contains multiple clusters of young stars. The Chandra data show that the X-ray sources in the field are found in small clumps, with a clear concentration of more than 100 sources in the central cluster, called G49.5−0.4 (pan over the image to find this source.)

Although the W51 giant molecular cloud fills the entire field-of-view of this image, there are large areas where Chandra does not detect any diffuse, low energy X-rays from hot interstellar gas. Presumably dense regions of cooler material have displaced this hot gas or blocked X-rays from it.

One of the massive stars in W51 is a bright X-ray source that is surrounded by a concentration of much fainter X-ray sources, as shown in a close-up view of the Chandra image. This suggests that massive stars can form nearly in isolation, with just a few lower mass stars rather than the full set of hundreds that are expected in typical star clusters.

Another young, massive cluster located near the center of W51 hosts a star system that produces an extraordinarily large fraction of the highest energy X-rays detected by Chandra from W51. Theories for X-ray emission from massive single stars can't explain this mystery, so it likely requires the close interaction of two very young, massive stars. Such intense, energetic radiation must change the chemistry of the molecules surrounding the star system, presenting a hostile environment for planet formation.

Image Credit: X-ray: NASA/CXC/PSU/L.Townsley et al; Infrared: NASA/JPL-Caltech
Explanation from: http://chandra.harvard.edu/photo/2017/w51/

July 11, 2017

Earth and Dragon Spacecraft seen from the International Space Station

Earth and Dragon Spacecraft seen from the International Space Station

NASA astronaut Jack Fischer photographed the SpaceX Dragon capsule as it reentered Earth's atmosphere before splashing down in the Pacific Ocean west of Baja California at 8:12 a.m. EDT, July 3, 2017. Fischer commented, "Beautiful expanse of stars-but the “long” orange one is SpaceX-11 reentering! Congrats team for a successful splashdown & great mission!"

A variety of technological and biological studies conducted on the International Space Station are returning in Dragon. The Fruit Fly Lab-02 experiment seeks to better understand the effects of prolonged exposure to microgravity on the heart. Samples from the Systemic Therapy of NELL-1 for osteoporosis will return as part of an investigation using rodents as models to test a new drug that can both rebuild bone and block further bone loss, improving crew health. The Cardiac Stem Cells experiment investigated how microgravity affects stem cells and the factors that govern stem cell activity.

The Dragon spacecraft launched June 3 on a SpaceX Falcon 9 rocket from historic Launch Complex 39A at NASA’s Kennedy Space Center in Florida, and arrived at the station June 5.

Image Credit: NASA
Explanation from: https://www.nasa.gov/image-feature/dragon-returns-space-station-science-to-earth

Jupiter's Great Red Spot and Earth

Jupiter's Great Red Spot and Earth

Measuring in at 10,159 miles (16,350 kilometers) in width (as of April 3, 2017) Jupiter's Great Red Spot is 1.3 times as wide as Earth. This composite image was generated by combining NASA imagery of Earth with an image of Jupiter taken by astronomer Christopher Go.

Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Christopher Go

Spiral Galaxy IC 342

Spiral Galaxy IC 342

IC 342 is a challenging cosmic target. Although it is bright, the galaxy sits near the equator of the Milky Way’s galactic disc, where the sky is thick with glowing cosmic gas, bright stars, and dark, obscuring dust. In order for astronomers to see the intricate spiral structure of IC 342, they must gaze through a large amount of material contained within our own galaxy — no mean feat! As a result IC 342 is relatively difficult to spot and image, giving rise to its intriguing nickname: the “Hidden Galaxy”.

Located very close (in astronomical terms!) to the Milky Way, this sweeping spiral galaxy would be among the brightest in the sky were it not for its dust-obscured location. The galaxy is very active, as indicated by the range of colours visible in this NASA/ESA Hubble Space Telescope image, depicting the very central region of the galaxy. A beautiful mixture of hot, blue star-forming regions, redder, cooler regions of gas, and dark lanes of opaque dust can be seen, all swirling together around a bright core. In 2003, astronomers confirmed this core to be a specific type of central region known as an HII nucleus — a name that indicates the presence of ionised hydrogen — that is likely to be creating many hot new stars.

Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1727a/

July 10, 2017



The light of a new day on Saturn illuminates the planet's wavy cloud patterns and the smooth arcs of the vast rings.

The light has traveled around 80 minutes since it left the sun's surface by the time it reaches Saturn. The illumination it provides is feeble; Earth gets 100 times the intensity since it's roughly ten times closer to the sun. Yet compared to the deep blackness of space, everything at Saturn still shines bright in the sunlight, be it direct or reflected.

This view looks toward the sunlit side of the rings from about 10 degrees above the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on Feb. 25, 2017 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 939 nanometers.

The view was obtained at a distance of approximately 762,000 miles (1.23 million kilometers) from Saturn. Image scale is 45 miles (73 kilometers) per pixel.

Image Credit: NASA/JPL-Caltech/Space Science Institute
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21336

Artist's illustration of unlensed source galaxy

Artist's illustration of unlensed source galaxy

This artist’s illustration portrays what the gravitationally lensed galaxy SDSS J1110+6459 might look like up close. A sea of young, blue stars is streaked with dark dust lanes and studded with bright pink patches that mark sites of ongoing star formation. The patches’ signature glow comes from ionized hydrogen, like we see in the Orion Nebula in our own galaxy.

According to new research, these distant star-formation regions are clumpy and span about 200 to 300 light-years. This contradicts earlier theories suggesting that such regions might be much larger, 3000 light-years or more in size.

Image Credit: NASA, ESA, and Z. Levay (STScI)
Explanation from: https://www.spacetelescope.org/images/opo1727c/

Galaxy Cluster SDSS J1110+6459

Galaxy Cluster SDSS J1110+6459

The galaxy cluster shown here, SDSS J1110+6459, was discovered as part of the Sloan Giant Arcs Survey. It is located about 6 billion light-years from Earth (redshift of z=0.659) and contains hundreds of galaxies. At left, a distinctive blue arc is actually composed of three separate images of a more distant background galaxy called SGAS J111020.0+645950.8. This background galaxy has been magnified, distorted, and multiply imaged by the gravity of the galaxy cluster in a process known as gravitational lensing.

Image Credit: NASA, ESA, and T. Johnson (University of Michigan)
Explanation from: https://www.spacetelescope.org/images/opo1727b/

July 9, 2017

Spiral Galaxy Messier 77

Spiral Galaxy Messier 77

ESO’s Very Large Telescope (VLT) has captured a magnificent face-on view of the barred spiral galaxy Messier 77. The image does justice to the galaxy’s beauty, showcasing its glittering arms criss-crossed with dust lanes — but it fails to betray Messier 77’s turbulent nature.

This picturesque spiral galaxy appears to be tranquil, but there is more to it than meets the eye. Messier 77 (also known as NGC 1068) is one of the closest active galaxies, which are some of the most energetic and spectacular objects in the Universe. Their nuclei are often bright enough to outshine the whole of the rest of the galaxy. Active galaxies are among the brightest objects in the Universe and emit light at most, if not all, wavelengths, from gamma rays and X-rays all the way to microwaves and radiowaves. Messier 77 is further classified as a Type II Seyfert galaxy, characterised by being particularly bright at infrared wavelengths.

This impressive luminosity is caused by intense radiation blasting out from a central engine — the accretion disc surrounding a supermassive black hole. Material that falls towards the black hole is compressed and heated up to incredible temperatures, causing it to radiate a tremendous amount of energy. This accretion disc is thought to be enshrouded by thick doughnut-shaped structure of gas and dust, called a “torus”. Observations of Messier 77 back in 2003 were the first to resolve such a structure using the powerful VLT Interferometer.

This image of Messier 77 was taken in four different wavelength bands represented by blue, red, violet and pink (hydrogen-alpha) colours. Each wavelength brings out a different quality: for example, the pinkish hydrogen-alpha highlights the hotter and younger stars forming in the spiral arms, while in red are the fine, thread-like filamentary structures in the gas surrounding Messier 77. A foreground Milky Way star is also seen beside the galaxy centre, displaying tell-tale diffraction spikes. Additionally, many more distant galaxies are visible; sitting at the outskirts of the spiral arms, they appear tiny and delicate compared to the colossal active galaxy .

Located 47 million light-years away in the constellation of Cetus (The Sea Monster), Messier 77 is one of the most remote galaxies of the Messier catalogue. Initially, Messier believed that the highly luminous object he saw through his telescope was a cluster of stars, but as technology progressed its true status as a galaxy was realised. At approximately 100 000 light-years across, Messier 77 is also one of largest galaxies in the Messier catalogue — so massive that its gravity causes other nearby galaxies to twist and become warped.

This image was obtained using the FOcal Reducer and low dispersion Spectrograph 2 (FORS2) instrument mounted on Unit Telescope 1 (Antu) of the VLT, located at ESO’s Paranal Observatory in Chile. It hails from ESO’s Cosmic Gems programme, an outreach initiative that produces images of interesting, intriguing or visually attractive objects using ESO telescopes for the purposes of education and outreach.

Image Credit: ESO
Explanation from: https://www.eso.org/public/news/eso1720/

Hakumyi Crater, Ceres

Hakumyi Crater, Ceres

NASA's Dawn spacecraft took this image of Hakumyi Crater on Ceres, visible left of center. The crater is named after a Paraguayan, Brazilian and Bolivian spirit said to be helpful in gardening.

Hakumyi, 18 miles (29 kilometers) in diameter, is located about 43 miles (70 kilometers) west of Ernutet Crater. Ernutet is where scientists found evidence of organic material, thanks to Dawn's visible and infrared mapping spectrometer.

Evidence for organics was also found at the 4-mile (6.5 kilometer) wide fresh crater on the southern rim of Hakumyi and on the lobe-shaped flow of material that runs into Hakumyi. These two features look relatively young in comparison to the rest of Hakumyi Crater, whose rims and overall shape are subdued. The lobate flow is reminiscent of the Type I flows identified in multiple places at high latitudes on Ceres, and suggests a significant amount of ice near the surface.

Dawn took this image on August 20, 2015, from 915 miles (1,470 kilometers) altitude. The center coordinates of this image are 48.9 degrees north latitude and 27.0 degrees east longitude.

Image Credit: NASA
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21413

Streaming Prominence

Streaming Prominence

A prominence at the edge of the Sun provided us with a splendid view of solar plasma as it churned and streamed over less than one day (June 25-26, 2017). The charged particles of plasma were being manipulated by strong magnetic forces. When viewed in this wavelength of extreme ultraviolet light, we can trace the movements of the particles. Such occurrences are fairly common but much easier to see when they are near the Sun's edge. For a sense of scale, the arch of prominence in the still image has risen up several times the size of Earth.

Image Credit: NASA/GSFC/Solar Dynamics Observatory
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21768

July 1, 2017

Hekla Volcano Eruption

Hekla Volcano Eruption

Hekla, Iceland

Image Credit: Vilhelm Gunnarsson

The map of the Milky Way Galaxy

The map of the Milky Way Galaxy

Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy, the Milky Way. Using infrared images from NASA's Spitzer Space Telescope, scientists have discovered that the Milky Way's elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. Previously, our galaxy was thought to possess four major arms.

This annotated artist's concept illustrates the new view of the Milky Way, along with other findings presented at the 212th American Astronomical Society meeting in St. Louis, Mo. The galaxy's two major arms (Scutum-Centaurus and Perseus) can be seen attached to the ends of a thick central bar, while the two now-demoted minor arms (Norma and Sagittarius) are less distinct and located between the major arms. The major arms consist of the highest densities of both young and old stars; the minor arms are primarily filled with gas and pockets of star-forming activity.

The artist's concept also includes a new spiral arm, called the "Far-3 kiloparsec arm," discovered via a radio-telescope survey of gas in the Milky Way. This arm is shorter than the two major arms and lies along the bar of the galaxy.

Our Sun lies near a small, partial arm called the Orion Arm, or Orion Spur, located between the Sagittarius and Perseus arms.

Image Credit: NASA/JPL-Caltech/R. Hurt (SSC/Caltech)
Explanation from: http://www.spitzer.caltech.edu/images/1925-ssc2008-10b-A-Roadmap-to-the-Milky-Way-Annotated-

Jupiter seen by Juno spacecraft in Near Infrared

Jupiter seen by Juno spacecraft in Near Infrared

This composite infrared image of Jupiter reveals haze particles over a range of altitudes, as seen in reflected sunlight. It was taken using the Gemini North Telescope's Near-InfraRed Imager (NIRI) on May 18, 2017, in collaboration with the investigation of Jupiter by NASA's Juno mission. Juno completed its sixth close approach to Jupiter a few hours after this observation.

The multiple filters corresponding to each color used in the image cover wavelengths between 1.69 microns and 2.275 microns. Jupiter's Great Red Spot (GRS) appears as the brightest (white) region at these wavelengths, which are primarily sensitive to high-altitude clouds and hazes near and above the top of Jupiter's convective region.

The GRS is one of the highest-altitude features in Jupiter's atmosphere. Narrow spiral streaks that appear to lead into it or out of it from surrounding regions probably represent atmospheric features being stretched by the intense winds within the GRS, such as the hook-like structure on its western edge (left side). Some are being swept off its eastern edge (right side) and into an extensive wave-like flow pattern, and there is even a trace of flow from its northern edge.

Other features near the GRS include the dark block and dark oval to the south and the north of the eastern flow pattern, respectively, indicating a lower density of cloud and haze particles in those locations. Both are long-lived cyclonic circulations, rotating clockwise -- in the opposite direction as the counterclockwise rotation of the GRS.

A prominent wave pattern is evident north of the equator, along with two bright ovals, which are anticyclones that appeared in January 2017. Both the wave pattern and the ovals may be associated with an impressive upsurge in stormy activity that has been observed in these latitudes this year. Another bright anticyclonic oval is seen further north. The Juno spacecraft may pass over these ovals, as well as the Great Red Spot, during its close approach to Jupiter on July 10, 2017, Pacific Time (July 11, Universal Time).

High hazes are evident over both polar regions with much spatial structure not previously been seen quite so clearly in ground-based images

The filters used for observations combined into this image admit infrared light centered on the following infrared wavelengths (and presented here in these colors): 1.69 microns (blue), 2.045 microns (cyan), 2.169 microns (green), 2.124 microns (yellow), and 2.275 microns (red).

Image Credit: Gemini Observatory/AURA/NASA/JPL-Caltech
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21713

June 30, 2017

Earth, Aurora and the International Space Station

Earth, Aurora and the International Space Station

Expedition 52 Flight Engineer Jack Fischer of NASA photographed the glowing nighttime lights of an aurora from his vantage point in the International Space Station's cupola module on June 19, 2017. Part of the station's solar array is also visible.

ISS, Orbit of the Earth
June 19, 2017

Image Credit: NASA

Elliptical Galaxy 4C 73.08

Elliptical Galaxy 4C 73.08

Luminous galaxies glow like fireflies on a dark night in this image snapped by the NASA/ESA Hubble Space Telescope. The central galaxy in this image is a gigantic elliptical galaxy designated 4C 73.08. A prominent spiral galaxy seen from "above" shines in the lower part of the image, while examples of galaxies viewed edge-on also populate the cosmic landscape.

In the optical and near-infrared light captured to make this image, 4C 73.08 does not appear all that beastly. But when viewed in longer wavelengths the galaxy takes on a very different appearance. Dust-piercing radio waves reveal plumes emanating from the core, where a supermassive black hole spews out twin jets of material. 4C 73.08 is classified as a radio galaxy as a result of this characteristic activity in the radio part of the electromagnetic spectrum.

Astronomers must study objects such as 4C 73.08 in multiple wavelengths in order to learn their true natures, just as seeing a firefly’s glow would tell a scientist only so much about the insect. Observing 4C 73.08 in visible light with Hubble illuminates galactic structure as well as the ages of constituent stars, and therefore the age of the galaxy itself. 4C 73.08 is decidedly redder than the prominent, bluer spiral galaxy in this image. The elliptical galaxy’s redness comes from the presence of many older, crimson stars, which shows that 4C 73.08 is older than its spiral neighbour.

The image was taken using Hubble’s Wide Field Camera 3 through two filters: one which captures green light, and one which captures red and near-infrared light.

Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1246a/

IRAS 21078+5211

IRAS 21078+5211

This image shows an outflow of gas from a new star as it jets from a space object dubbed IRAS 21078+5211, among other designations. The reddish blob in its center, as picked up by Spitzer's 4.5 micron infrared band, contrasts nicely with the green PAHs that surround it. These telltale outflow features of young, hulking stars show up well even without the longer wavelengths available to the original GLIMPSE survey that ran during the "cold" segment of Spitzer's mission. These so-called shocked outflows ram into the hydrogen gas around them and make it glow - a bright beacon in the lonely outskirts of the Milky Way.

This image is a combination of data from Spitzer and the Two Micron All Sky Survey (2MASS). The Spitzer data was taken after Spitzer's liquid coolant ran dry in May 2009, marking the beginning of its "warm" mission. Light from Spitzer's remaining infrared channels at 3.6 and 4.5 microns has been represented in green and red, respectively. 2MASS 2.2 micron light is blue.

Image Credit: NASA/JPL-Caltech/2MASS/B. Whitney (SSI/University of Wisconsin)
Explanation from: http://www.spitzer.caltech.edu/images/3224-sig10-014-A-Shocking-Outflow

NASA Wallops Rocket Launch Lights up the Mid-Atlantic Coast

NASA Wallops Rocket Launch Lights up the Mid-Atlantic Coast

NASA Terrier-Improved Malemute sounding rocket was successfully launched at 4:25 a.m., Thursday, June 29, from the agency’s Wallops Flight Facility in Virginia.

During the 8-minute flight, 10 canisters about the size of a soft drink can were ejected in space, 6 to 12 miles away from the 670-pound main payload.

The canisters deployed blue-green and red vapor that formed artificial clouds visible from New York to North Carolina.

During an ionosphere or aurora science mission, these clouds, or vapor tracers, allow scientists on the ground to visually track particle motions in space.

The development of the multi-canister ampoule ejection system will allow scientists to gather information over a much larger area than previously possible when deploying the tracers just from the main payload.

The rocket, after being delayed multiple times over the last 30 days, flew to an altitude of about 118 miles.

Wallops received nearly 2,000 reports and photos of the cloud sightings from areas as far north as New York, south to North Carolina, and inland throughout Virginia, Maryland, Pennsylvania, and points in-between.

NASA's Wallops Flight Facility provides agile, low-cost flight and launch range services to meet government and commercial sector needs for accessing flight regimes worldwide from the Earth’s surface to the moon. Wallops' flight assets ranging from research aircraft, unmanned aerial systems and high-altitude balloons to suborbital and orbital rockets provide a full-range of capability, while operational launch range and airfield capabilities meet ongoing and emerging needs in the science, aerospace, defense, and commercial industries.

Image Credit: NASA
Explanation from: https://www.nasa.gov/feature/wallops/2017/nasa-wallops-rocket-launch-lights-up-the-mid-atlantic-coast

The Coma Galaxy Cluster

The Coma Galaxy Cluster

  • Long arms of hot gas been discovered in the Coma cluster of galaxies.
  • These arms were likely formed by hot gas being stripped and left behind smaller clusters of galaxies as they merged with Coma.
  • These arms span at least a half a million light years.
  • Galaxies clusters are the largest structures in the Universe held together by gravity.

A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by using NASA's Chandra X-ray Observatory and ESA's XMM-Newton. These features, which span at least half a million light years, provide insight into how the Coma cluster has grown through mergers of smaller groups and clusters of galaxies to become one of the largest structures in the Universe held together by gravity.

A new composite image, with Chandra data in pink and optical data from the Sloan Digital Sky Survey appearing in white and blue, features these spectacular arms (mouse over the image for their location). In this image, the Chandra data have been processed so extra detail can be seen.

The X-ray emission is from multimillion-degree gas and the optical data shows galaxies in the Coma Cluster, which contain only about 1/6 the mass in hot gas. Only the brightest X-ray emission is shown here, to emphasize the arms, but the hot gas is present over the entire field of view.

Researchers think that these arms were most likely formed when smaller galaxy clusters had their gas stripped away by the head wind created by the motion of the cluster through the hot gas, in much the same way that the headwind created by a roller coaster blows the hats off riders.

Coma is an unusual galaxy cluster because it contains not one, but two giant elliptical galaxies near its center. These two giant elliptical galaxies are probably the vestiges from each of the two largest clusters that merged with Coma in the past. The researchers also uncovered other signs of past collisions and mergers in the data.

From their length, and the speed of sound in the hot gas (~4 million km/hr), the newly discovered X-ray arms are estimated to be about 300 million years old, and they appear to have a rather smooth shape. This gives researchers some clues about the conditions of the hot gas in Coma. Most theoretical models expect that mergers between clusters like those in Coma will produce strong turbulence, like ocean water that has been churned by many passing ships. Instead, the smooth shape of these lengthy arms points to a rather calm setting for the hot gas in the Coma cluster, even after many mergers.

Large-scale magnetic fields are likely responsible for the small amount of turbulence that is present in Coma. Estimating the amount of turbulence in a galaxy cluster has been a challenging problem for astrophysicists. Researchers have found a range of answers, some of them conflicting, and so observations of other clusters are needed.

Two of the arms appear to be connected to a group of galaxies located about two million light years from the center of Coma. One or both of these arms connects to a larger structure seen in the XMM-Newton data, and spans a distance or at least 1.5 million light years. A very thin tail also appears behind one of the galaxies in Coma. This is probably evidence of gas being stripped from a single galaxy, in addition to the groups or clusters that have merged there.

Image Credit: X-ray: NASA/CXC/MPE/J.Sanders et al, Optical: SDSS
Explanation from: http://chandra.harvard.edu/photo/2013/coma/

Supernova Remnant G299.2-2.9

Supernova Remnant G299.2-2.9

  • G299.2-2.9 is a supernova remnant found about 16,000 light years from Earth in the Milky Way galaxy.
  • It is the remains of a Type Ia supernova, the class of explosions astronomers use to measure the accelerating Universe and dark energy.
  • High-mass stars are those that contain 8 times the Sun's mass or more.
  • Because it is older than most Type Ia remnants astronomers have found, G299.2-2.9 gives a look at how the remnants evolve over time.

G299.2-2.9 is an intriguing supernova remnant found about 16,000 light years away in the Milky Way galaxy . Evidence points to G299.2-2.9 being the remains of a Type Ia supernova, where a white dwarf has grown sufficiently massive to cause a thermonuclear explosion. Because it is older than most supernova remnants caused by these explosions, at an age of about 4500 years, G299.2-2.9 provides astronomers with an excellent opportunity to study how these objects evolve over time. It also provides a probe of the Type Ia supernova explosion that produced this structure.

This composite image shows G299.2-2.9 in X-ray light from Chandra, along with data from the ROSAT satellite (orange), that has been overlaid on an infrared image from the Two Micron All-Sky Survey (2MASS). The faint X-ray emission from the inner region reveals relatively large amounts of iron and silicon, as expected for a remnant of a Type Ia supernova. The outer shell of the remnant is complex, with at least a double shell structure. Typically, such a complex outer shell is associated with a star that has exploded into space where gas and dust are not uniformly distributed.

Since most theories to explain Type Ia supernovas assume they go off in a uniform environment, detailed studies of this complicated outer shell should help astronomers improve their understanding of the environments where these explosions occur. It is very important to understand the details of Type Ia explosions because astronomers use them as cosmic mile markers to measure the accelerated expansion of the universe and study dark energy. The discovery of this accelerated expansion in the late 1990s led to the recent award of the Nobel Prize in Physics.

Image Credit: X-ray: NASA/CXC/U. Texas at Arlington/S.Park et al, ROSAT; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF
Explanation from: http://chandra.harvard.edu/photo/2011/g299/

June 28, 2017

Dwarf Galaxy UGC 8201

Dwarf Galaxy UGC 8201

The galaxy UGC 8201, captured here by the NASA/ESA Hubble Space Telescope, is a dwarf irregular galaxy, so called because of its small size and chaotic structure. It lies just under 15 million light-years away from us in the constellation of Draco (the Dragon). As with most dwarf galaxies it is a member of a larger group of galaxies. In this case UCG 8201 is part of the M81 galaxy group; this group is one of the closest neighbours to the Local Group of galaxies, which contains our galaxy, the Milky Way.

UGC 8201 is at an important phase in its evolution. It has recently finished a long period of star formation, which had significant impact on the whole galaxy. This episode lasted for several hundred million years and produced a high number of newborn bright stars. These stars can be seen in this image as the dominating light source within the galaxy. This process also changed the distribution and amount of dust and gas in between the stars in the galaxy.

Such large star formation events need extensive sources of energy to trigger them. However, compared to larger galaxies, dwarf galaxies lack such sources and they do not appear to have enough gas to produce as many new stars as they do. This raises an important unanswered question in galaxy evolution: How do relatively isolated, low-mass systems such as dwarf galaxies sustain star formation for extended periods of time?

Due to its relative proximity to Earth UGC 8201 is an excellent object for research and provides an opportunity to improve our understanding of how dwarf galaxies evolve and grow.

Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1510a/

Wide-field view of the sky around the young star HL Tauri

Wide-field view of the sky around the young star HL Tauri

This image shows the region in which HL Tauri is situated. HL Tauri is part of one of the closest star-forming regions to Earth and there are many young stars, as well as clouds of dust, in its vicinity. This picture was created from images forming part of the Digitized Sky Survey 2.

Explanation from: ESO/Digitized Sky Survey 2

Globular Cluster NGC 6752

Globular Cluster NGC 6752

Looking like a hoard of gems fit for an emperor’s collection, this deep sky object called NGC 6752 is in fact far more worthy of admiration. It is a globular cluster, and at over 10 billion years old is one the most ancient collections of stars known. It has been blazing for well over twice as long long as our Solar System has existed.

NGC 6752 contains a high number of “blue straggler” stars, some of which are visible in this image. These stars display characteristics of stars younger than their neighbours, despite models suggesting that most of the stars within globular clusters should have formed at approximately the same time. Their origin is therefore something of a mystery.

Studies of NGC 6752 may shed light on this situation. It appears that a very high number — up to 38% — of the stars within its core region are binary systems. Collisions between stars in this turbulent area could produce the blue stragglers that are so prevalent.

Lying 13 000 light-years distant, NGC 6752 is far beyond our reach, yet the clarity of Hubble’s images brings it tantalisingly close.

Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1205a/

Lightning and Wildfire

Lightning and Wildfire

A new NASA-funded study finds that lightning storms were the main driver of recent massive fire years in Alaska and northern Canada, and that these storms are likely to move farther north with climate warming, potentially altering northern landscapes.

The study, led by Vrije Universiteit Amsterdam and the University of California, Irvine, examined the cause of the fires, which have been increasing in number in recent years. There was a record number of lightning-ignited fires in the Canadian Northwest Territories in 2014 and in Alaska in 2015. The team found increases of between two and five percent a year in the number of lightning-ignited fires since 1975.

To study the fires, the team analyzed data from NASA’s Terra and Aqua satellites and from ground-based lightning networks.

Lead author Sander Veraverbeke of Vrije Universiteit Amsterdam, who conducted the work while at UC Irvine, said that while the drivers of large fire years in the high north are still poorly understood, the observed trends are consistent with climate change.

“We found that it is not just a matter of more burning with higher temperatures. The reality is more complex: higher temperatures also spur more thunderstorms. Lightning from these thunderstorms is what has been igniting many more fires in these recent extreme events,” Veraverbeke said.

Study co-author Brendan Rogers at Woods Hole Research Center in Falmouth, Massachusetts, said these trends are likely to continue. “We expect an increasing number of thunderstorms, and hence fires, across the high latitudes in the coming decades as a result of climate change.” This is confirmed in the study by different climate model outputs.

Study co-author Charles Miller of NASA’s Jet Propulsion Laboratory in Pasadena, California, said while data from the lightning networks were critical to this study, it is challenging to use these data for trend detection because of continuing network upgrades. “A spaceborne sensor that provides high northern latitude lightning data that can be linked with fire dynamics would be a major step forward,” he said.

The researchers found that the fires are creeping farther north, near the transition from boreal forests to Arctic tundra. “In these high-latitude ecosystems, permafrost soils store large amounts of carbon that become vulnerable after fires pass through,” said co-author James Randerson of the University of California, Irvine. “Exposed mineral soils after tundra fires also provide favorable seedbeds for trees migrating north under a warmer climate.”

“Taken together, we discovered a complex feedback loop between climate, lightning, fires, carbon and forests that may quickly alter northern landscapes,” Veraverbeke concluded. “A better understanding of these relationships is critical to better predict future influences from climate on fires, and from fires on climate.”

Explanation from: https://www.nasa.gov/feature/jpl/lightning-sparking-more-boreal-forest-fires/

Coils of Magnetic Field Lines

Coils of Magnetic Field Lines

A smallish solar filament looks like it collapsed into the Sun and set off a minor eruption that hurled plasma into space (June 20, 2017). Then, the disrupted magnetic field immediately began to reorganize itself, hence the bright series of spirals coiling up over that area. The magnetic field lines are made visible in extreme ultraviolet light as charged particles spin along them. Also of interest are the darker, cooler strands of plasma being pulled and twisted at the edge of the Sun just below the active region.

Image Credit: NASA/GSFC/Solar Dynamics Observatory
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21764

The 2XMM J143450.5+033843 Galaxy

The 2XMM J143450.5+033843 Galaxy

Not all galaxies have the luxury of possessing a simple moniker or quirky nickname. The subject of this NASA/ESA Hubble Space Telescope image was one of the unlucky ones, and goes by the rather unpoetic name of 2XMM J143450.5+033843.

Such a name may seem like a random jumble of numbers and letters, but like all galactic epithets it has a distinct meaning. This galaxy, for example, was detected and observed as part of the second X-ray sky survey performed by ESA’s XMM-Newton Observatory. Its celestial coordinates form the rest of the bulky name, following the “J”: a right ascension value of 14h 34m 50.5s (this can be likened to terrestrial longitude), and a declination of +03d 38m 43s (this can be likened to terrestrial latitude). The other fuzzy object in the frame was named in the same way — it is a bright galaxy named 2XMM J143448.3+033749.

2XMM J143450.5+033843 lies nearly 400 million light-years away from Earth. It is a Seyfert galaxy that is dominated by something known as an Active Galactic Nucleus — its core is thought to contain a supermassive black hole that is emitting huge amounts of radiation, pouring energetic X-rays out into the Universe.

Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1726a/

June 26, 2017



This orange blob shows the nearby star Betelgeuse, as seen by the Atacama Large Millimeter/submillimeter Array (ALMA). This is the first time that ALMA has ever observed the surface of a star and this first attempt has resulted in the highest-resolution image of Betelgeuse available.

Betelgeuse is one of the largest stars currently known — with a radius around 1400 times larger than the Sun’s in the millimeter continuum. About 600 light-years away in the constellation of Orion (The Hunter), the red supergiant burns brightly, causing it to have only a short life expectancy. The star is just about eight million years old, but is already on the verge of becoming a supernova. When that happens, the resulting explosion will be visible from Earth, even in broad daylight.

The star has been observed in many other wavelengths, particularly in the visible, infrared, and ultraviolet. Using ESO’s Very Large Telescope astronomers discovered a vast plume of gas almost as large as our Solar System. Astronomers have also found a gigantic bubble that boils away on Betelgeuse’s surface. These features help to explain how the star is shedding gas and dust at tremendous rates. In this picture, ALMA observes the hot gas of the lower chromosphere of Betelgeuse at sub-millimeter wavelengths — where localised increased temperatures explain why it is not symmetric. Scientifically, ALMA can help us to understand the extended atmospheres of these hot, blazing stars.

Image Credit: ALMA (ESO/NAOJ/NRAO)/E. O’Gorman/P. Kervella
Explanation from: https://www.eso.org/public/images/potw1726a/

Colliding Galaxies Arp 299

Colliding Galaxies Arp 299

  • Arp 299 is a system where two galaxies are in the process of merging.
  • Chandra data has revealed 25 bright point-like X-ray sources in Arp 299, 14 of which are categorized as "ULXs".
  • These ULXs are likely binary systems where a black hole or neutron star is pulling material from a companion star.
  • Such a high concentration of ULXs is rare, but caused by a high rate of star formation triggered by the galactic merger.

What would happen if you took two galaxies and mixed them together over millions of years? A new image including data from NASA's Chandra X-ray Observatory reveals the cosmic culinary outcome.

Arp 299 is a system located about 140 million light years from Earth. It contains two galaxies that are merging, creating a partially blended mix of stars from each galaxy in the process.

However, this stellar mix is not the only ingredient. New data from Chandra reveals 25 bright X-ray sources sprinkled throughout the Arp 299 concoction. Fourteen of these sources are such strong emitters of X-rays that astronomers categorize them as "ultra-luminous X-ray sources," or ULXs.

These ULXs are found embedded in regions where stars are currently forming at a rapid rate. Most likely, the ULXs are binary systems where a neutron star or black hole is pulling matter away from a companion star that is much more massive than the Sun. These double star systems are called high-mass X-ray binaries.

Such a loaded buffet of high-mass X-ray binaries is rare, but Arp 299 is one of the most powerful star-forming galaxies in the nearby Universe. This is due at least in part to the merger of the two galaxies, which has triggered waves of star formation. The formation of high-mass X-ray binaries is a natural consequence of such blossoming star birth as some of the young massive stars, which often form in pairs, evolve into these systems.

This new composite image of Arp 299 contains X-ray data from Chandra (pink), higher-energy X-ray data from NuSTAR (purple), and optical data from the Hubble Space Telescope (white and faint brown). Arp 299 also emits copious amounts of infrared light that has been detected by observatories such as NASA's Spitzer Space Telescope, but those data are not included in this composite.

The infrared and X-ray emission of the galaxy is remarkably similar to that of galaxies found in the very distant Universe, offering an opportunity to study a relatively nearby analog of these distant objects. A higher rate of galaxy collisions occurred when the universe was young, but these objects are difficult to study directly because they are located at colossal distances.

The Chandra data also reveal diffuse X-ray emission from hot gas distributed throughout Arp 299. Scientists think the high rate of supernovas, another common trait of star-forming galaxies, has expelled much of this hot gas out of the center of the system.

Image Credit: X-ray: NASA/CXC/Univ of Crete/K. Anastasopoulou et al, NASA/NuSTAR/GSFC/A. Ptak et al; Optical: NASA/STScI
Explanation from: http://chandra.harvard.edu/photo/2017/arp299/



NASA's Cassini spacecraft peers toward a sliver of Saturn's sunlit atmosphere while the icy rings stretch across the foreground as a dark band.

This view looks toward the unilluminated side of the rings from about 7 degrees below the ring plane. The image was taken in green light with the Cassini spacecraft wide-angle camera on March 31, 2017.

The view was obtained at a distance of approximately 620,000 miles (1 million kilometers) from Saturn. Image scale is 38 miles (61 kilometers) per pixel.

Image Credit: NASA/JPL-Caltech/Space Science Institute
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21334

June 25, 2017

Andromeda Galaxy, Triangulum Galaxy and VLT Telescope

Andromeda Galaxy, Triangulum Galaxy and VLT Telescope

This stunning image of the clear Chilean sky shows a speckling of bright stars and distant galaxies across the frame, all suspended above one of the four Unit Telescopes (UTs) of the Very Large Telescope (VLT). This is the fourth UT and it is known as Yepun (Venus).

Two objects seen in this frame are more famous than their neighbours. In the left hand portion of the image is a fairly prominent galaxy that forms a streak across the sky — Messier 31, or the Andromeda Galaxy. Upwards and to the right of this smudge is a bright star, which in turn points upwards to a galaxy that lies roughly along the same extended line. This star is named Beta Andromedae — otherwise known as Mirach — and the second galaxy is Messier 33 (at the top of the frame). These two galaxies are thought to have interacted in the past, forming a bridge of hydrogen gas that spans the gap between them.

Image Credit: ESO/B. Tafreshi
Explanation from: https://www.eso.org/public/images/potw1342a/

Jupiter's Clouds

Jupiter's Clouds

This enhanced-color image of Jupiter's bands of light and dark clouds was created by citizen scientists Gerald Eichstädt and Seán Doran using data from the JunoCam imager on NASA's Juno spacecraft.

Three of the white oval storms known as the "String of Pearls" are visible near the top of the image. Each of the alternating light and dark atmospheric bands in this image is wider than Earth, and each rages around Jupiter at hundreds of miles (kilometers) per hour. The lighter areas are regions where gas is rising, and the darker bands are regions where gas is sinking.

Juno acquired the image on May 19, 2017, at 11:30 a.m. PST (2:30 p.m. EST) from an altitude of about 20,800 miles (33,400 kilometers) above Jupiter's cloud tops.

Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt/Sean Doran
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21393

Galaxy Cluster MACS J2129-0741

Galaxy Cluster MACS J2129-0741

This image is a wide-field view of the galaxy cluster MACS J2129-0741, located in the constellation Aquarius (the Water-Bearer). The massive galaxy cluster magnifies, brightens, and distorts the images of remote background galaxies, including the far-distant, dead disc galaxy MACS2129-1.

Image Credit: NASA, ESA, Marc Postman (STScI), and the CLASH team