A Split Ion Tail for Comet Lovejoy E4

A Split Ion Tail for Comet Lovejoy E4:

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2017 April 25

Explanation: What's happened to Comet Lovejoy? In the pictured image, a processed composite, the comet was captured early this month after brightening unexpectedly and sporting a long and intricate ion tail. Remarkably, the typically complex effect of the Sun's wind and magnetic field here caused the middle of Comet Lovejoy's ion tail to resemble the head of a needle. Comet C/2017 E4 (Lovejoy) was discovered only last month by noted comet discoverer Terry Lovejoy. The comet reached visual magnitude 7 earlier this month, making it a good target for binoculars and long duration exposure cameras. What's happened to Comet Lovejoy (E4) since this image was taken might be considered even more remarkable -- the comet's nucleus appeared to be disintegrating and fading as it neared its closest approach to the Sun two days ago.

Mt. Etna Lava Plume

Mt. Etna Lava Plume:

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2017 April 26

Mt. Etna Lava Plume

Image Credit & Copyright: Dario Giannobile


Explanation: Mt. Etna has been erupting for hundreds of thousands of years. Located in Sicily, Italy, the volcano produces lava fountains over one kilometer high. Mt. Etna is not only one of the most active volcanoes on Earth, it is one of the largest, measuring over 50 kilometers at its base and rising nearly 3 kilometers high. Pictured in mid-March, a spectacular lava plume erupts upwards, dangerous molten volcanic bombs fly off to the sides, while hot lava flows down the volcano's exterior. The Earth's rotation is discernable on this carefully time, moon-lit, long duration image as star trails.

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Tomorrow's picture: April showers

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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Exploring the Antennae

Exploring the Antennae:

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2017 April 28

Explanation: Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. Stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm that lasts for hundreds of millions of years. But the galaxies' large clouds of molecular gas and dust often do, triggering furious episodes of star formation near the center of the cosmic wreckage. Spanning over 500 thousand light-years, this stunning view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkable mosaicked image was constructed using data from the ground-based Subaru telescope to bring out large-scale and faint tidal streams, and Hubble Space Telescope data of extreme detail in the bright cores. The suggestive visual appearance of the extended arcing structures gives the galaxy pair its popular name - The Antennae.

Arches of Spring

Arches of Spring:

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2017 April 29

Arches of Spring

Image Credit & Copyright: Ondrej Kralik


Explanation: Two luminous arches stretched across the dome of the sky on this northern spring night. After sunset on March 29, the mountain view panorama was captured in 57 exposures from Chopok peak in central Slovakia at an altitude of about 2,000 meters. The arc of the northern Milky Way is visible toward the right, but only after it reaches above the terrestrial lights from the mountain top perspective. Though dusk has passed, a bright patch of celestial light still hovers near the horizon and fades into a second luminous arch of Zodiacal Light, crossing near the center of the Milky Way. Dust in the ecliptic plane reflects sunlight to create the Zodiacal glow, typically prominent after sunset in clear, dark, skies of the northern spring. Almost opposite the Sun, Jupiter shines brightly near the horizon toward the left. Since Jupiter lies near the ecliptic, it appears within the slight brightening of the Zodiacal band also opposite the Sun called the Gegenschein.



Tomorrow's picture: looking out from Saturn

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Cassini Looks Out from Saturn

Cassini Looks Out from Saturn:

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2017 April 30

Cassini Looks Out from Saturn

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


Explanation: 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 image taken a few hours before closest approach, Saturn's unusual northern hexagon is seen surrounding the North Pole. Saturn's B ring is the closest visible, while the dark Cassini Division separates B from the outer A. A close inspection will find the two small 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 to end its mission by plunging into Saturn's atmosphere on September 15.

Tomorrow's picture: glowing neutron star

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Cooling Neutron Star

Cooling Neutron Star:

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2017 May 1

Cooling Neutron Star

Image Credit: X-ray: NASA/CXC/UNAM/Ioffe/D.Page, P. Shternin et al; Optical: NASA/STScI;

Illustration: NASA/CXC/M. Weiss


Explanation: The bright source near the center is a neutron star, the incredibly dense, collapsed remains of a massive stellar core. Surrounding it is supernova remnant Cassiopeia A (Cas A), a comfortable 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.

Tomorrow's picture: sunset approach

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NGC 3628: The Hamburger Galaxy

NGC 3628: The Hamburger Galaxy:

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2017 May 3

Explanation: No, hamburgers are not this big. What is pictured is a sharp telescopic view of a magnificent edge-on spiral galaxy NGC 3628, a puffy galactic disk divided by dark dust lanes. Of course, this deep galactic portrait puts some astronomers in mind of its popular moniker, The Hamburger Galaxy. The tantalizing island universe is about 100,000 light-years across and 35 million light-years away in the northern springtime constellation Leo. NGC 3628 shares its neighborhood in the local Universe with two other large spirals M65 and M66 in a grouping otherwise known as the Leo Triplet. Gravitational interactions with its cosmic neighbors are likely responsible for the extended flare and warp of this spiral's disk.

The Perseus Cluster Waves

The Perseus Cluster Waves:

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2017 May 4

The Perseus Cluster Waves

Image Credit: NASA, CXC, GSFC, Stephen Walker, et al.


Explanation: 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 the Chandra 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.

Tomorrow's picture: bull's eye, crescent moon

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The Bull's Eye and the Young Moon

The Bull's Eye and the Young Moon:

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2017 May 5

Explanation: Aldebaran, eye of Taurus the Bull, and a young crescent Moon shared an early evening sky last Friday. The lovely celestial pairing could be enjoyed around planet Earth, but from some locations the Moon was even seen to pass in front of Aldebaran, a dramatic lunar occultation of the familiar bright star. Taken at nightfall on April 28, this skyscape captures Aldebaran shortly after it emerged from behind the bright lunar limb. In the foreground are craggy peaks of the Dolomite mountains near Laggio di Cadore, Italy. Before reappearing beyond the sunlit crescent, Aldebaran first winked out behind the Moon's ashen glow, the lunar nightside faintly illuminated by earthshine.

Galaxy Cluster Abell 370 and Beyond

Galaxy Cluster Abell 370 and Beyond:

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2017 May 6

Galaxy Cluster Abell 370 and Beyond

Image Credit: NASA, ESA, Jennifer Lotz and the HFF Team (STScI)


Explanation: 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 Fields project.

Tomorrow's picture: child stars

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Star Formation in the Tadpole Nebula

Star Formation in the Tadpole Nebula:

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2017 May 7

Star Formation in the Tadpole Nebula

Image Credit: WISE, IRSA, NASA; Processing & Copyright: Francesco Antonucci


Explanation: What's all of the commotion in the Tadpole nebula? Star formation. Dusty emission in the Tadpole nebula, IC 410, lies about 12,000 light-years away in the northern constellation of the Charioteer (Auriga). The cloud of glowing gas is over 100 light-years across, sculpted by stellar winds and radiation from embedded open star cluster NGC 1893. Formed in the interstellar cloud a mere 4 million years ago, bright newly formed cluster stars are seen all around the star-forming nebula. Notable near the image center are two relatively dense streamers of material trailing away from the nebula's central regions. Potentially sites of ongoing star formation in IC 410, these cosmic tadpole shapes are about 10 light-years long. The featured image was taken in infrared light by NASA's Wide Field Infrared Survey Explorer (WISE) satellite.

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Tomorrow's picture: sands and hills of mars

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Big Dipper Above and Below Chilean Volcanoes

Big Dipper Above and Below Chilean Volcanoes:

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2017 May 9

Big Dipper Above and Below Chilean Volcanoes

Image Credit & Copyright: Yuri Beletsky (Carnegie Las Campanas Observatory, TWAN)


Explanation: Do you see it? This common question frequently precedes the rediscovery of one of the most commonly recognized configurations of stars on the northern sky: the Big Dipper. This grouping of stars is one of the few things that has likely been seen, and will be seen, by every generation. The Big Dipper is not by itself a constellation. Although part of the constellation of the Great Bear (Ursa Major), the Big Dipper is an asterism that has been known by different names to different societies. Five of the Big Dipper stars are actually near each other in space and were likely formed at nearly the same time. Connecting two stars in the far part of the Big Dipper will lead one to Polaris, the North Star, which is part of the Little Dipper. Relative stellar motions will cause the Big Dipper to slowly change its configuration over the next 100,000 years. Pictured in late April, the Big Dipper was actually imaged twice -- above and below distant Chilean volcanoes, the later reflected from an unusually calm lagoon.

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Tomorrow's picture: galaxy upset

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UGC 1810: Wildly Interacting Galaxy from Hubble

UGC 1810: Wildly Interacting Galaxy from Hubble:

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2017 May 10

UGC 1810: Wildly Interacting Galaxy from Hubble

Image Credit: NASA, ESA, Hubble, HLA; Processing & Copyright: Domingo Pestana


Explanation: What's happening to this spiral galaxy? Although details remain uncertain, it surely has to do with an ongoing battle with its smaller galactic neighbor. The featured galaxy is labelled UGC 1810 by itself, but together with its collisional partner is known as Arp 273. The overall shape of the UGC 1810 -- in particular its blue outer ring -- is likely a result of wild and violent gravitational interactions. This ring's blue color is caused by massive stars that are blue hot and have formed only in the past few million years. The inner galaxy appears older, redder, and threaded with cool filamentary dust. A few bright stars appear well in the foreground, unrelated to UGC 1810, while several galaxies are visible well in the background. Arp 273 lies about 300 million light years away toward the constellation of Andromeda. Quite likely, UGC 1810 will devour its galactic sidekick over the next billion years and settle into a classic spiral form.

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Tomorrow's picture: adventures across the spectrum

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The Multiwavelength Crab

The Multiwavelength Crab:

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2017 May 11

The Multiwavelength Crab

Image Credit: NASA, ESA, G. Dubner (IAFE, CONICET-University of Buenos Aires) et al.;

A. Loll et al.; T. Temim et al.; F. Seward et al.; VLA/NRAO/AUI/NSF; Chandra/CXC;

Spitzer/JPL-Caltech; XMM-Newton/ESA; Hubble/STScI


Explanation: The Crab Nebula is cataloged as M1, the first object on Charles Messier's famous list of things which are not comets. In fact, the Crab is now known to be a supernova remnant, expanding debris from massive star's death explosion, witnessed on planet Earth in 1054 AD. This brave new image offers a 21st century view of the Crab Nebula by presenting image data from across the electromagnetic spectrum as wavelengths of visible light. From space, Chandra (X-ray) XMM-Newton (ultraviolet), Hubble (visible), and Spitzer (infrared), data are in purple, blue, green, and yellow hues. From the ground, Very Large Array radio wavelength data is in shown in red. One of the most exotic objects known to modern astronomers, the Crab Pulsar, a neutron star spinning 30 times a second, is the bright spot near picture center. Like a cosmic dynamo, this collapsed remnant of the stellar core powers the Crab's emission across the electromagnetic spectrum. Spanning about 12 light-years, the Crab Nebula is 6,500 light-years away in the constellation Taurus.



Tomorrow's picture: 100,000 reasons

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M13: The Great Globular Cluster in Hercules

M13: The Great Globular Cluster in Hercules:

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2017 May 12

M13: The Great Globular Cluster in Hercules

Image Credit & Copyright: Adam Block, Mt. Lemmon SkyCenter, U. Arizona


Explanation: In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shews itself to the naked Eye, when the Sky is serene and the Moon absent." Of course, M13 is now less modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Telescopic views reveal the spectacular cluster's hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter. Approaching the cluster core upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison, the closest star to the Sun is over 4 light-years away. Along with the cluster's dense core, the outer reaches of M13 are highlighted in this sharp color image. The cluster's evolved red and blue giant stars show up in yellowish and blue tints.



Tomorrow's picture: the great light-weekend

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Planet Aurora

Planet Aurora:

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2017 May 13

Explanation: What bizarre alien planet is this? It's planet Earth of course, seen from the International Space Station through the shimmering glow of aurorae. About 400 kilometers (250 miles) above Earth, the orbiting station is itself within the upper realm of the auroral displays. Aurorae have the signature colors of excited molecules and atoms at the low densities found at extreme altitudes. Emission from atomic oxygen dominates this view. The eerie glow is green at lower altitudes, but a rarer reddish band extends above the space station's horizon. Also visible from the planet's surface, this auroral display began during a geomagnetic storm. The storm was triggered after a coronal mass ejection impacted Earth's magnetosphere in June of 2015.

Black Hole Accreting with Jet

Black Hole Accreting with Jet:

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2017 March 27

Explanation: What happens when a black hole devours a star? Many details remain unknown, but recent observations are providing new clues. In 2014, a powerful explosion was recorded by the ground-based robotic telescopes of the All Sky Automated Survey for SuperNovae (ASAS-SN) project, and followed up by instruments including NASA's Earth-orbiting Swift satellite. Computer modeling of these emissions fit a star being ripped apart by a distant supermassive black hole. The results of such a collision are portrayed in the featured artistic illustration. The black hole itself is a depicted as a tiny black dot in the center. As matter falls toward the hole, it collides with other matter and heats up. Surrounding the black hole is an accretion disk of hot matter that used to be the star, with a jet emanating from the black hole's spin axis.

King of Wings Hoodoo under the Milky Way

King of Wings Hoodoo under the Milky Way:

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2017 March 28

King of Wings Hoodoo under the Milky Way

Image Credit & Copyright: Wayne Pinkston (LightCrafter Photography)


Explanation: This rock structure is not only surreal -- it's real. The reason it's not more famous is that it is, perhaps, smaller than one might guess: the capstone rock overhangs only a few meters. Even so, the King of Wings outcrop, located in New Mexico, USA, is a fascinating example of an unusual type of rock structure called a hoodoo. Hoodoos may form when a layer of hard rock overlays a layer of eroding softer rock. Figuring out the details of incorporating this hoodoo into a night-sky photoshoot took over a year. Besides waiting for a suitably picturesque night behind a sky with few clouds, the foreground had to be artificially lit just right relative to the natural glow of the background. After much planning and waiting, the final shot, featured here, was taken in May 2016. Mimicking the horizontal bar, the background sky features the band of our Milky Way Galaxy stretching overhead.

Tomorrow's picture: shooting stars

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Nebula with Laser Beams

Nebula with Laser Beams:

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2017 March 29

Explanation: Four laser beams cut across this startling image of the Orion Nebula, as seen from ESO's Paranal Observatory in the Atacama desert on planet Earth. Not part of an interstellar conflict, the lasers are being used for an observation of Orion by UT4, one of the observatory's very large telescopes, in a technical test of an image-sharpening adaptive optics system. This view of the nebula with laser beams was captured by a small telescope from outside the UT4 enclosure. The beams are visible from that perspective because in the first few kilometers above the observatory the Earth's dense lower atmosphere scatters the laser light. The four small segments appearing beyond the beams are emission from an atmospheric layer of sodium atoms excited by the laser light at higher altitudes of 80-90 kilometers. Seen from the perspective of the UT4, those segments form bright spots or artificial guide stars. Their fluctuations are used in real-time to correct for atmospheric blurring along the line-of-sight by controlling a deformable mirror in the telescope's optical path.

Young Stars and Dusty Nebulae in Taurus

Young Stars and Dusty Nebulae in Taurus:

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2017 March 30

Young Stars and Dusty Nebulae in Taurus

Image Credit & Copyright: Lloyd L. Smith, Deep Sky West


Explanation: This complex of dusty nebulae lingers along the edge of the Taurus molecular cloud, a mere 450 light-years distant. Stars are forming on the cosmic scene. Composed from almost 40 hours of image data, the 2 degree wide telescopic field of view includes some youthful T-Tauri class stars embedded in the remnants of their natal clouds at the right. Millions of years old and still going through stellar adolescence, the stars are variable in brightness and in the late phases of their gravitational collapse. Their core temperatures will rise to sustain nuclear fusion as they grow into stable, low mass, main sequence stars, a stage of stellar evolution achieved by our middle-aged Sun about 4.5 billion years ago. Another youthful variable star, V1023 Tauri, can be spotted on the left. Within its yellowish dust cloud, it lies next to the striking blue reflection nebula Cederblad 30, also known as LBN 782. Just above the bright bluish reflection nebula is dusty dark nebula Barnard 7.



Tomorrow's picture: 3D67P

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NGC 602 and Beyond

NGC 602 and Beyond:

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2017 April 2

Explanation: Near the outskirts of the Small Magellanic Cloud, a satellite galaxy some 200 thousand light-years distant, lies 5 million year young star cluster NGC 602. Surrounded by natal gas and dust, NGC 602 is featured in this stunning Hubble image of the region, augmented by images in the X-ray by Chandra, and in the infrared by Spitzer. Fantastic ridges and swept back shapes strongly suggest that energetic radiation and shock waves from NGC 602's massive young stars have eroded the dusty material and triggered a progression of star formation moving away from the cluster's center. At the estimated distance of the Small Magellanic Cloud, the Picture spans about 200 light-years, but a tantalizing assortment of background galaxies are also visible in this sharp multi-colored view. The background galaxies are hundreds of millions of light-years or more beyond NGC 602.

Saturn in Infrared from Cassini

Saturn in Infrared from Cassini:

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2017 April 3

Explanation: 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 several infrared 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.

Plane Contrail and Sun Halo

Plane Contrail and Sun Halo:

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2017 April 4

Explanation: What's happened to the sky? Several common features of the daytime sky are interacting in uncommon ways. First, well behind the silhouetted hills, is the typically bright Sun. In front of the Sun are thin clouds, possibly the home to a layer of hexagonal ice crystals that together are creating the 22 degree halo of light surrounding the Sun. The unusual bent line that crosses the image is a contrail -- a type of cloud created by a passing airplane. Much of the contrail must actually be further away than the thin cloud because it casts a shadow onto the cloud, giving an unusual three-dimensional quality to the featured image. The featured image was taken in late January in the city of Patras in West Greece.

Filaments of Active Galaxy NGC 1275

Filaments of Active Galaxy NGC 1275:

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2017 April 5

Filaments of Active Galaxy NGC 1275

Image Credit: Hubble Legacy Archive, ESA, NASA; Processing & Copyright: Domingo Pestana


Explanation: What keeps these filaments attached to this galaxy? The filaments persist in NGC 1275 even though the turmoil of galactic collisions should destroy them. First, active galaxy NGC 1275 is the central, dominant member of the large and relatively nearby Perseus Cluster of Galaxies. Wild-looking at visible wavelengths, the active galaxy is also a prodigious source of x-rays and radio emission. NGC 1275 accretes matter as entire galaxies fall into it, ultimately feeding a supermassive black hole at the galaxy's core. This composite image, recreated from archival Hubble Space Telescope data, highlights the resulting galactic debris and filaments of glowing gas, some up to 20,000 light-years long. Observations indicate that the structures, pushed out from the galaxy's center by the black hole's activity, are held together by magnetic fields. Also known as Perseus A, NGC 1275 spans over 100,000 light years and lies about 230 million light years away.

Tomorrow's picture: open space

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