Sunday, June 25, 2017

The N44 Superbubble

What created this gigantic hole? The vastemission nebula N44 in our neighboring galaxy the Large Magellanic Cloud has a large, 250light-year hole and astronomers are trying to figure out why. One possibility is particle windsexpelled by massive stars in the bubble's interior that are pushing out the glowing gas. This answer was found to be inconsistent with measured wind velocities, however. Another possibility is that the expanding shells of oldsupernovas have sculpted the unusual space cavern. An unexpected clue of hot X-rayemitting gas was recently been detected escaping the N44 superbubble. The featured image was taken in three very specific colors by the huge 8-meter Gemini South Telescope onCerro Pachon in Chile.
Image Credit & CopyrightGemini Obs.AURA,NSF

Hubble uses Gravitational Lens to Capture Disk Galaxy

Acting as a “natural telescope” in space, the gravity of the extremely massive foreground galaxy cluster MACS J2129-0741 magnifies, brightens, and distorts the far-distant background galaxy MACS2129-1 in the upper-right corner of this image. (View an annotated image highlighting the gravitationally-lensed galaxy.)

By combining the power of this "natural lens" in space with the capability of NASA's Hubble Space Telescope, astronomers made a surprising discovery—the first example of a compact yet massive, fast-spinning, disk-shaped galaxy that stopped making stars only a few billion years after the big bang.  Finding such a galaxy early in the history of the universe challenges the current understanding of how massive galaxies form and evolve, say researchers. This is the first direct observational evidence that at least some of the earliest so-called "dead" galaxies — where star formation stopped — somehow evolve from a Milky Way-shaped disk into the giant elliptical galaxies we see today.

Read more: Hubble Captures Massive Dead Disk Galaxy that Challenges Theories of Galaxy Evolution

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

Hubble Space Telescope

Markarian's Chain to Messier 64

Top to bottom, this colorful and broad telescopic mosaic links Markarian's Chain of galaxies across the core of the Virgo Cluster to dusty spiral galaxy Messier 64. Galaxies are scattered through the field of view that spans some 20 full moons across a gorgeous night sky. The cosmic frame is also filled with foreground stars from constellations Virgo and the well-groomed Coma Berenices, and faint, dusty nebulae drifting above the plane of the Milky Way. Look carefully for Markarian's eyes. The famous pair of interacting galaxies is near the top, not far from M87, the Virgo cluster's giant elliptical galaxy. At the bottom, you can stare down Messier 64, also known as the Black Eye Galaxy. The Virgo Cluster is the closest large galaxy cluster to our own local galaxy group. Virgo Cluster galaxies are about 50 million light-years distant, but M64 lies a mere 17 million light-years away.
Image Credit & CopyrightRogelio Bernal Andreo (Deep Sky Colors)

Tuesday, June 20, 2017

The Massive Stars in Westerlund

Star cluster Westerlund 1 is home to some of the largest and most massive stars known. It is headlined by the star Westerlund 1-26, a red supergiant star so big that if placed in the center of our Solar System, it would extend out past the orbit of Jupiter. Additionally, the young star cluster is home to 3 other red supergiants, 6 yellow hypergiant stars, 24 Wolf-Rayet stars, and several even-more unusual stars that continue to be studied. Westerlund 1 is relatively close-by for a star cluster at a distance of 15,000 light years, givingastronomers a good laboratory to study the development of massive stars. The featured image of Westerlund 1 was taken by the Hubble Space Telescope toward the southernconstellation of the Altar (Ara). Although presently classified as a "super" open cluster,Westerlund 1 may evolve into a low massglobular cluster over the next billion years.
Image Credit: ESA/Hubble & NASA

Hubble Space Telescope

Thursday, June 15, 2017

Eliptical Galaxy with Outer Shells and Plumbs

Can you see them? This famous Messier object M89, a seemingly simple elliptical galaxy, is surrounded by faint shells and plumes. The cause of the shells is currently unknown, but possibly tidal tails related to debris left over from absorbing numerous small galaxies in the past billion years. Alternatively the shells may be like ripples in a pond, where a recent collision with another large galaxy created density waves that ripple through this galactic giant. Regardless of the actual cause, the featured imagehighlights the increasing consensus that at least some elliptical galaxies have formed in the recent past, and that the outer halos of most large galaxies are not really smooth but have complexities induced by frequent interactions with -- and accretions of -- smaller nearby galaxies. The halo of our own Milky Way Galaxy is one example of suchunexpected complexityM89 is a member of the nearby Virgo cluster of galaxies which lies about 50 million light years distant.
Image Credit & Copyright: Mark Hanson

Tuesday, June 13, 2017

The Great Nebula in Carina

In one of the brightest parts of Milky Way lies a nebula where some of the oddest things occur. NGC 3372, known as the Great Nebula in Carina, is home to massive stars and changing nebulas. The Keyhole Nebula (NGC 3324), the bright structure just to the right of the image center, houses several of these massive stars and has itself changed its appearance. The entire Carina Nebulacaptured here, spans over 300 light years and lies about 7,500 light-years away in the constellation of CarinaEta Carinae, themost energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, butthen faded dramatically. While Eta Carinae itself maybe on the verge of a supernova explosion,X-ray images indicate that much of the Great Nebula in Carina has been a veritable supernova factory.
Image Credit & Copyright: Amit Ashok Kamble

Monday, June 12, 2017

IC 418: The Spirograph Nebula

What is creating the strange texture of IC 418? Dubbed the Spirograph Nebula for its resemblance to drawings from a cyclical drawing toolplanetary nebula IC 418 showspatterns that are not well understood. Perhaps they are related to chaotic winds from the variable central star, which changes brightness unpredictably in just a few hours. By contrast, evidence indicates that only a few million years ago, IC 418 was probably a well-understood star similar to our Sun. Only a few thousand years ago, IC 418 was probably a common red giantstar. Since running out of nuclear fuel, though, the outer envelope has begun expanding outward leaving a hot remnant core destined to become a white-dwarf star, visible in the imagecenter. The light from the central core excites surrounding atoms in the nebula causing them to glow. IC 418 lies about 2000 light-years away and spans 0.3 light-years across. This false-color image taken from the Hubble Space Telescope reveals the unusual details.
Image Credit: NASAESA, and the Hubble Heritage Team (STScI/AURA);Acknowledgement: R. Sahai (JPL) et al.

Hubble Space Telescope

Saturday, June 10, 2017

Saturn in the Milky way

Saturn is near opposition in planet Earth's sky. Rising at sunset and shining brightly throughout the night, it also lies near a line-of-sight to crowded starfields, nebulae, and obscuring dust clouds along the Milky Way. Whitish Saturn is up and left of center in this gorgeous central Milky Way skyscape, a two panel mosaic recorded earlier this month. You can find the bright planet above the bowl of the dusty Pipe nebula, and just beyond the end of a dark riverto Antares, alpha star of the constellation Scorpius. For now the best views of the ringed giant planet are from the Saturn-orbiting Cassini spacecraft, though. Diving close, Cassini's Grand Finale orbit number 8 is in progress.
Image Credit & CopyrightMohammad Nouroozi

M27 not a Comet

While hunting for comets in the skies above 18th century France, astronomer Charles Messier diligently kept a list of the things he encountered that were definitely not comets. This is number 27 on his now famous not-a-comet list. In fact, 21st century astronomers would identify it as a planetary nebula, but it's not a planet either, even though it may appear round and planet-like in a small telescope. Messier 27 (M27) is an excellent example of agaseous emission nebula created as a sun-like star runs out of nuclear fuel in its core. The nebula forms as the star's outer layers are expelled into space, with a visible glow generated by atoms excited by the dying star's intense but invisible ultraviolet light. Known by the popular name of the Dumbbell Nebula, the beautifully symmetric interstellar gas cloud is over 2.5 light-years across and about 1,200 light-years away in the constellation Vulpecula.This spectacular color image incorporates broad and narrowband observations recorded by the 8.2 meter Subaru telescope.
Image Credit &Copyright:Data;Subaru, NAOJ,Assembly and Processing;Roberto Colombari

Tuesday, June 6, 2017

Beneath the Jupiter

Jupiter is stranger than we knew. NASA's Juno spacecraft has now completed its sixth swoop past Jupiter as it moves around its highlyelliptical orbit. PicturedJupiter is seen from below where, surprisingly, the horizontal bandsthat cover most of the planet disappear intoswirls and complex patterns. A line of white oval clouds is visible nearer to the equator.Recent results from Juno show that Jupiter's weather phenomena can extend deep below its cloud tops, and that Jupiter's magnetic fieldvaries greatly with location. Juno is scheduled to orbit Jupiter 37 times with each orbit taking about six weeks.
Image Credit: NASAJunoSwRIMSSSGerald Eichstädt & Seán Doran

Juno

Saturday, June 3, 2017

Spiral Galaxy NGC 6744

Big, beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across, larger than our own Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo appearing as a faint, extended object in small telescopes. We see the disk of the nearby island universe tilted towards our line of sight. This remarkably distinct and detailed galaxy portraitcovers an area about the angular size of the full moon. In it, the giant galaxy's yellowish core is dominated by the light from old, cool stars. Beyond the core, spiral arms filled with young blue star clusters and pinkish star forming regions sweep past a smaller satellite galaxy at the lower left, reminiscent of the Milky Way's satellite galaxy the Large Magellanic Cloud.
Image Credit & CopyrightDaniel Verschatse

Sunday, May 28, 2017

Star Cluster, Spiral Galaxy, Super Nova

A cosmic snapshot from May 19, this colorful telescopic field of view spans about 1 degree or 2 full moons on the sky. Spiky in appearance, foreground Milky Way stars are scattered toward the royal constellation Cepheus while stars of open cluster NGC 6939 gather about 5 thousand light-years in the distance near the top of the frame. Face-on spiral galaxy NGC 6946 is toward the lower left nearly 22 million light-years away. The helpful red lines identify recently discovered supernova SN 2017eaw, the death explosion of a massive star nestled in the galaxy's bluish spiral arms. In fact in the last 100 years, 10 supernovae have been discovered in NGC 6946. By comparison, the average rate of supernovae in our Milky Way is about 1 every 100 years or so. Of course, NGC 6946 is also known as The Fireworks Galaxy.
Image Credit & CopyrightPaolo Demaria

Saturday, May 27, 2017

Comet Clark is near the edge

Sweeping through this stunning field of view,Comet 71P/Clark really is in the foreground of these cosmic clouds. The 2 panel telescopic mosaic is color enhanced and is about 5 degrees (10 full moons) across. It captures thefaint comet's position on the night of May 23/24 over 5 light-minutes from Earth, very near the line-of-sight to bright star Antares and the Rho Ophiuchi cloud complex. In the frame Antares, also known as Alpha Scorpii, is at bottom center surrounded by a dusty cosmic cloud reflecting the cool giant star's yellowish light. Globular star cluster M4 shines just right of Antares, but M4 lies some 7,000 light-years away compared to Antares' 500 light-year distance. Slightly closer than Antares, Rho Ophiuchi's bluish starlight is reflected by the dust in molecular clouds toward the top. You can spot the small coma and short tail of the comet as a faint smudge near the center of the left edge of the frame. Just look for the comet's striking greenish color, produced as diatomic carbon molecules fluoresce in sunlight.
Image Credit & CopyrightRaul Villaverde Fraile

Tuesday, May 23, 2017

A View Towards M101

Big, beautiful spiral galaxy M101 is one of the last entries in Charles Messier's famous catalog, but definitely not one of the least. About 170,000 light-years across, this galaxy is enormous, almost twice the size of our own Milky Way galaxy. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. M101 shares this modern telescopic field of view with spiky foreground stars within the Milky Way, and more distant background galaxies. The colors of the Milky Way stars can also be found in the starlight from the large island universe. Its core is dominated by light from cool yellowish stars.Along its grand spiral arms are the blue colors of hotter, young stars mixed with obscuring dust lanes and pinkish star forming regions. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major, about 25 million light-years away.
Image Credit & CopyrightLaszlo Bagi

In the Center of Lagoon Nebula

The center of the Lagoon Nebula is a whirlwindof spectacular star formation. Visible on the lower left, at least two long funnel-shaped clouds, each roughly half a light-year long, have been formed by extreme stellar winds and intense energetic starlight. The tremendously bright nearby star, Hershel 36, lights the area. Vast walls of dust hide and redden other hot young stars. As energy from these stars pours into the cool dust and gas, large temperature differences in adjoining regions can be created generating shearing winds which may cause the funnels. This picture, spanning about 5 light years, was taken in 1995 by the orbiting Hubble Space Telescope. The Lagoon Nebula, also known as M8, lies about 5000 light years distant toward the constellation of Sagittarius.
Image Credit: Hubble, A. Caulet (ST-ECF, ESA),NASA

Sunday, May 7, 2017

Galaxy Cluster Abell 370 and Beyond

Some 4 billion light-years away, massive galaxy cluster Abell 370 only appears to be dominated by two giant elliptical galaxies and infested with faint arcs in this sharp Hubble Space Telescope snapshot. The fainter, scattered bluish arcs along with the dramatic dragon arc below and left of center are images of galaxies that lie far beyond Abell 370. About twice as distant, their otherwise undetected light is magnified and distorted by the cluster's enormous gravitational mass, dominated by unseen dark matter. Providing a tantalizing glimpse of galaxies in the early universe, the effect is known as gravitational lensing. A consequence of warped spacetime it was first predicted by Einstein a century ago. Far beyond the spiky foreground Milky Way star at lower right, Abell 370 is seen toward the constellation Cetus, the Sea Monster. It is the last of six galaxy clusters imaged in the recently concluded Frontier Fieldsproject.
Image Credit: NASAESA, Jennifer Lotz and theHFF Team (STScI)

The Perseus Cluster Waves

The cosmic swirl and slosh of giant waves in an enormous reservoir of glowing hot gas are traced in this enhanced X-ray image from theChandra Observatory. The frame spans over 1 million light-years across the center of the nearby Perseus Galaxy Cluster, some 240 million light-years distant. Like other clusters of galaxies, most of the observable mass in the Perseus cluster is in the form of the cluster-filling gas. With temperatures in the tens of millions of degrees, the gas glows brightly in X-rays. Computer simulations can reproduce details of the structures sloshing through the Perseus cluster's X-ray hot gas, including the remarkable concave bay seen below and left of center. About 200,000 light-years across, twice the size of the Milky Way, the bay's formation indicates that Perseus itself was likely grazed by a smaller galaxy cluster billions of years ago.
For image credit and copyright guidance, please visit the image websitehttp://antwrp.gsfc.nasa.gov/apod/ap170504.html

Chandra X-ray Observatory

Illustration of Earth-Size 'Tatooine' Planet

With two suns in its sky, Luke Skywalker's home planet Tatooine in "Star Wars" looks like a parched, sandy desert world. In real life, thanks to observatories such as NASA's Kepler space telescope, we know that two-star systems can indeed support planets, although planets discovered so far around double-star systems are large and gaseous. Scientists wondered: If an Earth-size planet were orbiting two suns, could it support life?

It turns out, such a planet could be quite hospitable if located at the right distance from its two stars, and wouldn't necessarily even have deserts. In a particular range of distances from two sun-like host stars, a planet covered in water would remain habitable and retain its water for a long time, according to an April 6, 2017 study in the journal Nature Communications.

This illustration shows a hypothetical planet covered in water around the binary star system of Kepler-35A and B. In reality, the stellar pair Kepler-35A and B host a planet called Kepler-35b, a giant planet about eight times the size of Earth, with an orbit of 131.5 Earth days. For their study, researchers neglected the gravitational influence of this planet and added a hypothetical water-covered, Earth-size planet around the Kepler-35 A and B stars. They examined how this planet’s climate would behave as it orbited the host stars with periods between 341 and 380 days.

More: Earth-Sized 'Tatooine' Planets Could Be Habitable

Image Credit: NASA/JPL-Caltech

Kepler

Wednesday, May 3, 2017

Cassini Looks out from Saturn

This is what Saturn looks like from inside the rings. Last week, for the first time, NASA directed the Cassini spacecraft to swoop between Saturn and its rings. During the dive, the robotic spacecraft took hundreds of images showing unprecedented detail for structures in Saturn's atmosphere. Looking back out, however, the spacecraft was also able to capture impressive vistas. In the featured imagetaken a few hours before closest approach,Saturn's unusual northern hexagon is seen surrounding the North Pole. Saturn's C ring is the closest visible, while the dark Cassini Division separates the inner B ring from the outer A. A close inspection will find the twosmall moons that shepherd the F-ring, the farthest ring discernable. This image is raw and will be officially verified, calibrated and released at a later date. Cassini remains on schedule toend its mission by plunging into Saturn's atmosphere on September 15.
Image Credit: NASAJPL-CaltechSpace Science Institute

Cassini

Cooling Neutron Star

The bright source near the center is a neutron star, the incredibly dense, collapsed remains of a massive stellar core. Surrounding it issupernova remnant Cassiopeia A (Cas A), acomfortable 11,000 light-years away. Light from the Cas A supernova, the death explosion of a massive star, first reached Earth about 350 years ago. The expanding debris cloud spans about 15 light-years in this composite X-ray/optical image. Still hot enough to emit X-rays, Cas A's neutron star is cooling. In fact, years of observations with the orbiting Chandra X-ray Observatory find that the neutron star is cooling rapidly -- so rapidly that researchers suspect a large part of the neutron star's core is forming a frictionless neutron superfluid. The Chandra results represent the first observational evidence for this bizarre state of neutron matter.
Image Credit: X-ray:NASA/CXC/UNAM/Ioffe/D.PageP. Shternin et al; Optical: NASA/STScI
Illustration: NASA/CXC/M. Weiss

Sunday, April 30, 2017

Hubble's Bright Shining Lizard Star

In space, being outshone is an occupational hazard. This NASA/ESA Hubble Space Telescope image captures a galaxy named NGC 7250. Despite being remarkable in its own right '” it has bright bursts of star formation and recorded supernova explosions'” it blends into the background somewhat thanks to the gloriously bright star hogging the limelight next to it.

The bright object seen in this Hubble image is a single and little-studied star named TYC 3203-450-1, located in the constellation of Lacerta (The Lizard). The star is much closer than the much more distant galaxy.

Only this way can a normal star outshine an entire galaxy, consisting of billions of stars. Astronomers studying distant objects call these stars 'foreground stars'� and they are often not very happy about them, as their bright light is contaminating the faint light from the more distant and interesting objects they actually want to study.

In this case, TYC 3203-450-1 is million times closer than NGC 7250, which lies more than 45 million light-years away from us.andnbsp; If the star were the same distance from us as NGC 7250, it would hardly be visible in this image.
andnbsp;

Image credit: ESA/Hubble andamp; NASA
Text credit: European Space Agency

Hubble Space Telescope

Hubble's Bright Shining Lizard Star

In space, being outshone is an occupational hazard. This NASA/ESA Hubble Space Telescope image captures a galaxy named NGC 7250. Despite being remarkable in its own right '” it has bright bursts of star formation and recorded supernova explosions'” it blends into the background somewhat thanks to the gloriously bright star hogging the limelight next to it.

The bright object seen in this Hubble image is a single and little-studied star named TYC 3203-450-1, located in the constellation of Lacerta (The Lizard). The star is much closer than the much more distant galaxy.

Only this way can a normal star outshine an entire galaxy, consisting of billions of stars. Astronomers studying distant objects call these stars 'foreground stars'� and they are often not very happy about them, as their bright light is contaminating the faint light from the more distant and interesting objects they actually want to study.

In this case, TYC 3203-450-1 is million times closer than NGC 7250, which lies more than 45 million light-years away from us.andnbsp; If the star were the same distance from us as NGC 7250, it would hardly be visible in this image.
andnbsp;

Image credit: ESA/Hubble andamp; NASA
Text credit: European Space Agency

Hubble Space Telescope

Friday, April 28, 2017

Cassini Captures Closest Images of Saturn's Atmosphere

This unprocessed image shows features in Saturn's atmosphere from closer than ever before. The view was captured by NASA's Cassini spacecraft during its first Grand Finale dive past the planet on April 26, 2017.

Credit: NASA/JPL-Caltech/Space Science Institute.

Cassini

Lyrids in Southern Skies

Earth's annual Lyrid meteor shower peaked before dawn on April 22nd, as our fair planet plowed through dust from the tail of long-periodcomet Thatcher. Seen from the high, dark, and dry Atacama desert a waning crescent Moon and brilliant Venus join Lyrid meteor streaks in this composited view. Captured over 5 hours on the night of April 21/22, the meteors stream away from the shower's radiant, a point not very far on the sky from Vega, alpha star of the constellation Lyra. The radiant effect is due to perspective as the parallel meteor tracks appearto converge in the distance. In the foreground are domes of the Las Campanas Observatory housing (left to right) the 2.5 meter du Pont Telescope and the 1.3 meter Optical Gravitational Lensing Experiment (OGLE) telescope.
Image Credit & CopyrightYuri Beletsky(Carnegie Las Campanas ObservatoryTWAN)

Wednesday, April 26, 2017

Between the Rings of Saturn

On April 12, as the Sun was blocked by the disk of Saturn the Cassini spacecraft camera looked toward the inner Solar System and the gas giant's backlit rings. At the top of the mosaicked view is the A ring with its broader Encke and narrower Keeler gaps visible. At the bottom is the F ring, bright due to the viewing geometry. The point of light between the rings is Earth, 1.4 billion kilometers in the distance. Look carefullyand you can even spot Earth's large moon, a pinprick of light to the planet's left. Today Cassini makes its final close approach to Saturn's own large moon Titan, using Titan's gravity to swing into the spacecraft's Grand Finale, the final set of orbits that will bring Cassini just inside Saturn's rings.
Image Credit: Cassini Imaging TeamSSIJPL,ESANASA

Cassini

Hubble's Cosmic Bubble

This entrancing image shows a few of the tenuous threads that comprise Sh2-308, a faint and wispy shell of gas located 5,200 light-years away in the constellation of Canis Major (The Great Dog).

Sh2-308 is a large bubble-like structure wrapped around an extremely large, bright type of star known as a Wolf-Rayet Star '” this particular star is called EZ Canis Majoris. These type of stars are among the brightest and most massive stars in the Universe, tens of times more massive than our own sun, and they represent the extremes of stellar evolution. Thick winds continually poured off the progenitors of such stars, flooding their surroundings and draining the outer layers of the Wolf-Rayet stars. The fast wind of a Wolf-Rayet star therefore sweeps up the surrounding material to form bubbles of gas.

EZ Canis Majoris is responsible for creating the bubble of Sh2-308 '” the star threw off its outer layers to create the strands visible here. The intense and ongoing radiation from the star pushes the bubble out farther and farther, blowing it bigger and bigger. Currently the edges of Sh2-308 are some 60 light-years apart!

Beautiful as these cosmic bubbles are, they are fleeting. The same stars that form them will also cause their death, eclipsing and subsuming them in violent supernova explosions.

Credit: ESA/Hubble andamp; NASA
Text credit: European Space Agency

Hubble Space Telescope

Saturday, April 22, 2017

NGC 4302 and NGC 4298

Seen edge-on, spiral galaxy NGC 4302 (left) lies about 55 million light-years away in the well-groomed constellation Coma Berenices. A member of the large Virgo Galaxy Cluster, it spans some 87,000 light-years, a little smaller than our own Milky Way. Like the Milky Way, NGC 4302's prominent dust lanes cut along the center of the galactic plane, obscuring and reddening the starlight from our perspective. Smaller companion galaxy NGC 4298 is also a dusty spiral. But tilted more nearly face-on to our view, NGC 4298 can show off dust lanes along spiral arms traced by the bluish light of young stars, as well as its bright yellowish core. In celebration of the 27th anniversary of the launch of the Hubble Space Telescope on April 24, 1990, astronomers used the legendary telescope to take this gorgeous visible light portrait of the contrasting galaxy pair.
Image Credit: NASAESA, M. Mutchler (STScI)

Wednesday, April 19, 2017

The Red Spider Planetary Nebula

Oh what a tangled web a planetary nebula can weave. The Red Spider Planetary Nebula shows the complex structure that can result when anormal star ejects its outer gases and becomes a white dwarf star. Officially tagged NGC 6537, this two-lobed symmetric planetary nebulahouses one of the hottest white dwarfs ever observed, probably as part of a binary starsystem. Internal winds emanating from the central stars, visible in the center, have been measured in excess of 1000 kilometers per second. These winds expand the nebula, flow along the nebula's walls, and cause waves of hot gas and dust to collide. Atoms caught in these colliding shocks radiate light shown in the above representative-color picture by theHubble Space Telescope. The Red Spider Nebula lies toward the constellation of the Archer (Sagittarius). Its distance is not well known but has been estimated by some to be about 4,000 light-years.
Image Credit: NASAESAHubbleHLA;Reprocessing & Copyright: Jesús M.Vargas & Maritxu Poyal

Hubble Space Telescope

Tuesday, April 18, 2017

Watercolor World

When imaged at infrared wavelengths that pierce the planet’s upper haze layer, the high-speed winds of Saturn's atmosphere produce watercolor-like patterns.

With no solid surface creating atmospheric drag, winds on Saturn can reach speeds of more than 1,100 miles per hour (1,800 kilometers per hour) -- some of the fastest in the solar system.

This view was taken from a vantage point about 28 degrees above Saturn's equator. The image was taken with the Cassini spacecraft wide-angle camera on Dec. 2, 2016, with a combination of spectral filters which preferentially admits wavelengths of near-infrared light centered at 728 nanometers.

The view was acquired at a distance of approximately 592,000 miles (953,000 kilometers) from Saturn. Image scale is 35 miles (57 kilometers) per pixel.

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

Credit: NASA/JPL-Caltech/Space Science Institute

Cassini

Hubble sees Starbursts in Virgo

Although galaxy formation and evolution are still far from being fully understood, the conditions we see within certain galaxies -- such as so-called starburst galaxies  -- can tell us a lot about how they have evolved over time. Starburst galaxies contain a region (or many regions) where stars are forming at such a breakneck rate that the galaxy is eating up its gas supply faster than it can be replenished!

NGC 4536 is such a galaxy, captured here in beautiful detail by the Hubble?s Wide Field Camera 3 (WFC3). Located roughly 50 million light-years away in the constellation of Virgo (The Virgin), it is a hub of extreme star formation. There are several different factors that can lead to such an ideal environment in which stars can form at such a rapid rate. Crucially, there has to be a sufficiently massive supply of gas. This might be acquired in a number of ways -- for example by passing very close to another galaxy, in a full-blown galactic collision, or as a result of some event that forces lots of gas into a relatively small space.

Star formation leaves a few tell-tale fingerprints, so astronomers can tell where stars have been born. We know that starburst regions are rich in gas. Young stars in these extreme environments often live fast and die young, burning extremely hot and exhausting their gas supplies fairly quickly. These stars also emit huge amounts of intense ultraviolet light, which blasts the electrons off any atoms of hydrogen lurking nearby (a process called ionization), leaving behind often colorful clouds of ionized hydrogen (known in astronomer-speak as HII regions).

Credit: ESA/Hubble & NASA
Text Credit: European Space Agency

Hubble Space Telescope

Illustration of Cassini Space craft Diving through Plum of 'Ocean world' Enceladus

This illustration shows NASA's Cassini spacecraft diving through the plume of Saturn's moon Enceladus, in 2015. Two veteran NASA missions are providing new details about icy, ocean-bearing moons of Jupiter and Saturn, further heightening the scientific interest of these and other "ocean worlds" in our solar system and beyond.

Sunday, April 16, 2017

Leo Trio Galaxies

This group is popular in the northern spring. Famous as the Leo Triplet, the three magnificent galaxies gather in one field of view. Crowd pleasers when imaged with even modest telescopes, they can be introduced individually as NGC 3628 (left), M66 (bottom right), and M65 (top). All three are large spiral galaxies but they tend to look dissimilar because their galactic disks are tilted at different angles to our line of sight. NGC 3628 is seen edge-on, with obscuring dust lanes cutting across the plane of the galaxy, while the disks of M66 andM65 are both inclined enough to show off their spiral structure. Gravitational interactions between galaxies in the group have also left telltale signs, including the warped and inflated disk of NGC 3628 and the drawn out spiral arms of M66. This gorgeous view of the region spans about one degree (two full moons) on the sky. The field covers over 500 thousand light-years at the trio's estimated distance of 30 million light-years.
Image Credit & CopyrightIgnacio Diaz Bobillo

Saturday, April 15, 2017

Man, Sun and Dog

This was supposed to be a shot of trees in front of a setting Sun. Sometimes, though, the unexpected can be photogenic. During some planning shots, a man walking his dogunexpected crossed the ridge. The result was so striking that, after cropping, it became the main shot. The reason the Sun appears so largeis that the image was taken from about a kilometer away through a telephoto lens. Scattering of blue light by the Earth's atmosphere makes the bottom of the Sun appear slightly more red that the top. Also, if you look closely at the Sun, just above the man's head, a large group of sunspots is visible. The image was taken just last week in BadMergentheimGermany.
Image Credit & Copyright: Jens Hackmann

Tuesday, April 11, 2017

Castle Eye View

The best known asterism in northern skies, The Big Dipper is easy to recognize, even when viewed upside down, though some might see aplough or wagon. The star names and the familiar outlines appear framed in the ruined tower walls of the French Chateau du Morimontif you just slide your cursor over the image or follow this linkDubhe, alpha star of the dipper's parent constellation Ursa Major is at the lower left. Together with beta star Merak the two forma line pointing the way to Polaris and the North Celestial Pole, hidden from view by the stones. Since the image was captured on March 30, you can follow a line from dipper stars Phecda and Megrez to spot the faint greenish glow ofComet 41P/Tuttle-Giacobini-Kresak below center, still within the castle eye view. The periodic comet made a remarkable closeapproach to planet Earth on April 1.
Image Credit & Copyright: Stephane Vetter (Nuits sacrees, TWAN)

Dark Nebula LDN 1622 and Barnard's Loop

The silhouette of an intriguing dark nebulainhabits this cosmic scene. Lynds' Dark Nebula (LDN) 1622 appears below center against a faint background of glowing hydrogen gas only easily seen in long telescopic exposures of the region. LDN 1622 lies near the plane of our Milky Way Galaxy, close on the sky to Barnard's Loop - a large cloud surrounding the richcomplex of emission nebulae found in the Belt and Sword of Orion. Arcs along a segment of Barnard's loop stretch across the top of the frame. But the obscuring dust of LDN 1622 is thought to be much closer than Orion's more famous nebulae, perhaps only 500 light-years away. At that distance, this 1 degree wide field of view would span less than 10 light-years.
Credit & Copyright: Leonardo Julio (Astronomia Pampeana)

Monday, April 10, 2017

Expedition 50 Soyuz MS 02 Landing

The Soyuz MS-02 spacecraft is seen as it lands with Expedition 50 Commander Shane Kimbrough of NASA and Flight Engineers Sergey Ryzhikov and Andrey Borisenko of Roscosmos near the town of Zhezkazgan, Kazakhstan on Monday, April 10, 2017 (Kazakh time).

Tuesday, April 4, 2017

Saturn in Infrared from Cassini

Many details of Saturn appear clearly in infrared light. Bands of clouds show great structure, including long stretching storms. Also quite striking in infrared is the unusual hexagonal cloud pattern surrounding Saturn's North Pole. Each side of the dark hexagon spans roughly the width of our Earth. The hexagon's existence was not predicted, and its origin and likely stability remains a topic of research. Saturn's famous rings circle the planet and cast shadows below the equator. The featured image was taken by the robotic Cassini spacecraft in 2014 in severalinfrared colors -- but only processed recently. In September, Cassini's mission will be brought to a dramatic conclusion as the spacecraft will be directed to dive into ringed giant.
Image Credit: NASAJPL-CaltechSSIProcessing: Maksim Kakitsev

Cassini

Hubble spots two interacting Galaxies defying cosmic Convention

Some galaxies are harder to classify than others. Here, Hubble’s trusty Wide Field Camera 3 (WFC3) has captured a striking view of two interacting galaxies located some 60 million light-years away in the constellation of Leo (The Lion). The more diffuse and patchy blue glow covering the right side of the frame is known as NGC 3447 — sometimes NGC 3447B for clarity, as the name NGC 3447 can apply to the overall duo. The smaller clump to the upper left is known as NGC 3447A.
Overall, we know NGC 3447 comprises a couple of interacting galaxies, but we’re unsure what each looked like before they began to tear one another apart. The two sit so close that they are strongly influenced and distorted by the gravitational forces between them, causing the galaxies to twist themselves into the unusual and unique shapes seen here. NGC 3447A appears to display the remnants of a central bar structure and some disrupted spiral arms, both properties characteristic of certain spiral galaxies. Some identify NGC 3447B as a former spiral galaxy, while others categorize it as being an irregular galaxy.
Image credit: ESA/Hubble & NASA
Text credit: European Space Agency

Saturday, April 1, 2017

Hubble's Double Galaxy Gaze: Leda and NGC 4424

Some astronomical objects have endearing or quirky nicknames, inspired by mythology or their own appearance. Take, for example, the constellation of Orion (The Hunter), the Sombrero Galaxy, the Horsehead Nebula, or even the Milky Way. However, the vast majority of cosmic objects appear in astronomical catalogs and are given rather less poetic names based on the order of their discovery.

Two galaxies are clearly visible in this Hubble image, the larger of which is NGC 4424. This galaxy is cataloged in the New General Catalog of Nebulae and Clusters of Stars (NGC), which was compiled in 1888. The NGC is one of the largest astronomical catalogs, which is why so many Hubble Pictures of the Week feature NGC objects. In total there are 7,840 entries in the catalog and they are also generally the larger, brighter, and more eye-catching objects in the night sky, and hence the ones more easily spotted by early stargazers.

The smaller, flatter, bright galaxy sitting just below NGC 4424 is named LEDA 213994. The Lyon-Meudon Extragalactic Database (LEDA) is far more modern than the NGC and contains millions of objects.

Many NGC objects still go by their initial names simply because they were christened within the NGC first. However, since astronomers can't resist a good acronym and 'Leda'� is more appealing than 'the LMED,'� the smaller galaxy is called "Leda." Leda was a princess in Ancient Greek mythology.

Text credit: European Space Agency
Image credit: ESA/Hubble andamp; NASA

Hubble Space Telescope

The Comet, the Owl and the Galaxy

Comet 41P/Tuttle-Giacobini-Kresak poses for a Messier moment in this telescopic snapshot from March 21. In fact it shares the 1 degree wide field-of-view with two well-known entries in the 18th century comet-hunting astronomer'sfamous catalog. Sweeping through northernspringtime skies just below the Big Dipper, the faint greenish comet was about 75 light-seconds from our fair planet. Dusty, edge-on spiral galaxy Messier 108 (bottom center) is more like 45 million light-years away. At upper right, the planetary nebula with an aging but intensely hot central star, the owlish Messier 97is only about 12 thousand light-years distant though, still well within our own Milky Way galaxy. Named for its discoverer and re-discoverers, this faint periodic comet was first sighted in 1858 and not again until 1907 and 1951. Matching orbit calculations indicated that the same comet had been observed at widely separated times. Nearing its best apparition and closest approach to Earth in over 100 years on April 1, comet 41P orbits the Sun with a period of about 5.4 years.
Image Credit & CopyrightBarry Riu

Thursday, March 30, 2017

Fast Stars and Rouge Planets in Orion Nebula

Start with the constellation of Orion. Below Orion's belt is a fuzzy area known as the Great Nebula of Orion. In this nebula is a bright star cluster known as the Trapezium, marked by four bright stars near the image center. The newly born stars in the Trapezium and surrounding regions show the Orion Nebula to be one of the most active areas of star formation to be found in our area of the GalaxyIn Orion, supernova explosions and close interactions between stars have created rogue planets and stars that rapidly move through space. Some of these fast stars have been found by comparing different images of this region taken by the Hubble Space Telescope many years apart. Many of the stars in the featured image, taken in visible and near-infrared light, appear unusually redbecause they are seen through dust that scatters away much of their blue light.
Image Credit: NASAESAHubble

Tuesday, March 28, 2017

Hubble's Glittering Frisbee Galaxy

This image from Hubble's Wide Field Camera 3 (WFC3) shows a section of NGC 1448, a spiral galaxy located about 50 million light-years from Earth in the little-known constellation of Horologium (The Pendulum Clock). We tend to think of spiral galaxies as massive and roughly circular celestial bodies, so this glittering oval does not immediately appear to fit the visual bill. What's going on?

Imagine a spiral galaxy as a circular frisbee spinning gently in space. When we see it face on, our observations reveal a spectacular amount of detail and structure '” a great example from Hubble is the telescope's view of Messier 51, otherwise known as the Whirlpool Galaxy. However, the NGC 1448 frisbee is very nearly edge-on with respect to Earth, giving it an appearance that is more oval than circular. The spiral arms, which curve out from NGC 1448's dense core, can just about be seen.

Although spiral galaxies might appear static with their picturesque shapes frozen in space, this is very far from the truth. The stars in these dramatic spiral configurations are constantly moving as they orbit around the galaxy's core, with those on the inside making the orbit faster than those sitting further out.

This makes the formation and continued existence of a spiral galaxy's arms something of a cosmic puzzle, because the arms wrapped around the spinning core should become wound tighter and tighter as time goes on '” but this is not what we see. This is known as the winding problem.

For Hubble's image of the Whirlpool Galaxy, visit: andnbsp;andnbsp;

http://hubblesite.org/image/1677/news_release/2005-12

Image credit: ESA/Hubble andamp; NASA

Text credit: European Space Agency

Hubble Space Telescope

Thursday, March 16, 2017

Farewell to Mimas

In its season of "lasts," NASA's Cassini spacecraft made its final close approach to Saturn's moon Mimas on January 30, 2017. At closest approach, Cassini passed 25,620 miles (41,230 kilometers) from Mimas. All future observations of Mimas will be from more than twice this distance.

This mosaic is one of the highest resolution views ever captured of the icy moon.

Close approaches to Mimas have been somewhat rare during Cassini's mission, with only seven flybys at distances of less than 31,000 miles (50,000 kilometers).

Mimas' surface is pockmarked with countless craters, the largest of which gives the icy moon its distinctive appearance. (See PIA12568 for more info on Mimas' distinctive crater, Herschel.)

Two versions of the mosaic are provided. In one, the left side, which is lit by reflected light from Saturn, has been enhanced in brightness in order to show the full surface. The second version features more natural illumination levels.

Imaging scientists combined ten narrow-angle camera images to create this mosaic view. The scene is an orthographic projection centered on terrain at 17.5 degrees south latitude, 325.4 degrees west longitude on Mimas. An orthographic view is most like the view seen by a distant observer looking through a telescope.

This mosaic was acquired at a distance of approximately 28,000 miles (45,000 kilometers) from Mimas. Image scale is approximately 820 feet (250 meters) per pixel. The images were taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 30, 2017.

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

Image Credit: NASA/JPL-Caltech/Space Science Institute

Cassini

The Cone Nebula From Hubble

Stars are forming in the gigantic dust pillar called the Cone Nebula. Cones, pillars, and majestic flowing shapes abound in stellar nurseries where natal clouds of gas and dust are buffeted by energetic winds from newborn stars. The Cone Nebula, a well-known example, lies within the bright galactic star-forming region NGC 2264. The Cone was captured in unprecedented detail in this close-up composite of several observations from the Earth-orbiting Hubble Space Telescope. While the Cone Nebula, about 2,500 light-years away in Monoceros, is around 7 light-years long, the region pictured here surrounding the cone's blunted head is a mere 2.5 light-years across. In our neck of the galaxy that distance is just over half way from our Sun to its nearest stellar neighbors in the Alpha Centauri star system. The massive star NGC 2264 IRS, seen by Hubble's infrared camera in 1997, is the likely source of the wind sculpting the Cone Nebula and lies off the top of the image. The Cone Nebula's reddish veil is produced by glowing hydrogen gas.
Image Credit: Hubble Legacy ArchiveNASAESA - Processing & LicenceJudy Schmidt

Hubble Space Telescope

Wednesday, March 15, 2017

Mimas the Big One

Mimas' gigantic crater Herschel lies near the moon's limb in this Cassini view.

A big enough impact could potentially break up a moon. Luckily for Mimas, whatever created Herschel was not quite big enough to cause that level of disruption.

When large impacts happen, they deliver tremendous amounts of energy -- sometimes enough to cause global destruction.  Even impacts that are not catastrophic can leave enormous, near-permanent scars on bodies like Mimas (246 miles or 396 kilometers across).

This view looks toward the anti-Saturn hemisphere of Mimas. North on Mimas is up and rotated 32 degrees to the left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Nov. 19, 2016.

The view was acquired at a distance of approximately 53,000 miles (85,000 kilometers) from Mimas. Image scale is 1,677 feet (511 meters) per pixel.

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

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

Credit: NASA/JPL-Caltech/Space Science Institute

Cassini

A Dark Winter Sky Over Monfrague National Park in Spain

You, too, can see a night sky like this. That is because Monfrague National Park inSpain, where this composite image was created, has recently had its night sky officially protected from potential future light pollution. Icons of the night sky that should continue to stand out during northern winter -- and are visible on the featured image -- include very bright stars like SiriusBetelgeuse, and Procyon, bright star clusters like the Pleiades, and, photographically, faint nebulas like theCalifornia and Rosette Nebulas. Even 100 years ago, many people were more familiar with a darker night sky than people today, primarily because of the modern light pollution. Other parks that have been similarly protected as dark-sky preserves include Death Valley National Park (USA) and Grasslands National Park(Canada). Areas such as the city of Flagstaff, Arizona and much of the Big Island of Hawaii also have their night skies protected.
Image Credit & Copyright: José Luis Quiñones (Entre Encinas y Estrellas)