Alpha News

Every Full Moon of 2021 shines in this year-spanning astrophoto project, a composite portrait of the familiar lunar nearside at each brightest lunar phase . Arranged by moonth , the year progresses in stripes beginning at the top. Taken with the same camera and lens the stripes are from Full Moon images all combined at the same pixel scale. The stripes still looked mismatched, but they show that the Full Moon's angular size changes throughout the year depending on its distance from Kolkata, India, planet Earth. The calendar month , a full moon name, distance in kilometers, and angular size is indicated for each stripe. Angular size is given in minutes of arc corresponding to 1/60th of a degree. The largest Full Moon is near a perigee or closest approach in May. The smallest is near an apogee , the most distant Full Moon in December. Of course the full moons of May and November also slid into Earth's shadow during 2021's two lunar eclipses. from NASA https://ift.tt/3FW

This timelapse gif tracks the James Webb Space Telescope as it streaks across the stars of Orion on its journey to a destination beyond the Moon. Recorded on December 28, 12 consecutive exposures each 10 minutes long were aligned and combined with a subsequent color image of the background stars to create the animation. About 2.5 days after its December 25 launch, JWST cruised past the altitude of the Moon's orbit as it climbed up the gravity ridge from Earth to reach a halo orbit around L2, an Earth-Sun Lagrange point . Lagrange points are convenient locations in space where the combined gravitational attraction of one massive body (Earth) orbiting another massive body (Sun) is in balance with the centripetal force needed to move along with them . So much smaller masses, like spacecraft, will tend to stay there. One of 5 Lagrange points, L2 is about 1.5 million kilometers from Earth directly along the Earth-Sun line. JWST will arrive at L2 on January 23, 29 days after launch. W

Comet Leonard , brightest comet of 2021, is at the lower left of these two panels captured on December 29 in dark Atacama desert skies. Heading for its perihelion on January 3 Comet Leonard's visible tail has grown. Stacked exposures with a wide angle lens (also displayed in a reversed B/W scheme for contrast), trace the complicated ion tail for an amazing 60 degrees, with bright Jupiter shining near the horizon at lower right. Material vaporizing from Comet Leonard's nucleus , a mass of dust, rock, and ices about 1 kilometer across, has produced the long tail of ionized gas fluorescing in the sunlight. Likely flares on the comet's nucleus and buffeting by magnetic fields and the solar wind in recent weeks have resulted in the tail's irregular pinched and twisted appearance . Still days from its closest approach to the Sun, Comet Leonard's activity should continue. The comet is south of the Solar System's ecliptic plane as it sweeps through the southern con

What and where are these large ovals? They are rotating storm clouds on Jupiter imaged last month by NASA's Juno spacecraft . In general, higher clouds are lighter in color, and the lightest clouds visible are the relatively small clouds that dot the lower oval. At 50 kilometers across, however, even these light clouds are not small. They are so high up that they cast shadows on the swirling oval below. The featured image has been processed to enhance color and contrast. Large oval s are usually regions of high pressure that span over 1000 kilometers and can last for years. The largest oval on Jupiter is the Great Red Spot (not pictured), which has lasted for at least hundreds of years. Studying cloud dynamics on Jupiter with Juno images enables a better understanding of dangerous typhoons and hurricanes on Earth. from NASA https://ift.tt/3ezhb8d

What's happened to the Sun? Sometimes it looks like the Sun is being viewed through a giant lens . In the featured video, however, there are actually millions of tiny lenses: ice crystals . Water may freeze in the atmosphere into small, flat, six-sided, ice crystals. As these crystals flutter to the ground, much time is spent with their faces flat and parallel to the ground. An observer may find themselves in the same plane as many of the falling ice crystals near sunrise or sunset. During this alignment, each crystal can act like a miniature lens, refracting sunlight into our view and creating phenomena like parhelia , the technical term for sundogs . The featured video was taken in late 2017 on the side of a ski hill at the Vemdalen Ski Resort in central Sweden . Visible in the center is the most direct image of the Sun , while two bright sundogs glow prominently from both the left and the right. Also visible is the bright 22 degree halo -- as well as the rarer and muc

By Carl Zimmer from NYT Science https://ift.tt/3qv0Cjh

Which one of these two streaks is a comet? Although they both have comet-like features, the lower streak is the only real comet. This lower streak shows the coma and tail of Comet Leonard , a city-sized block of rocky ice that is passing through the inner Solar System as it continues its looping orbit around the Sun. Comet Leonard has recently passed its closest to both the Earth and Venus and will round the Sun next week. The comet, still visible to the unaided eye, has developed a long and changing tail in recent weeks. In contrast, the upper streak is the launch plume of the Ariane V rocket that lifted the James Webb Space Telescope (JWST) off the Earth two days ago. The featured single-exposure image was taken from Thailand , and the foreground spire is atop a pagoda in Doi Inthanon National Park . JWST , NASA's largest and most powerful space telescope so far, will orbit the Sun near the Earth-Sun L2 point and is scheduled to start science observations in the summe

There's a big new telescope in space. This one, the James Webb Space Telescope (JWST), not only has a mirror over five times larger than Hubble 's in area, but can see better in infrared light. The featured picture shows JWST high above the Earth just after being released by the upper stage of an Ariane V rocket, launched yesterday from French Guiana . Over the next month, JWST will move out near the Sun-Earth L2 point where it will co-orbit the Sun with the Earth. During this time and for the next five months, JWST will unravel its segmented mirror and an array of sophisticated scientific instruments -- and test them. If all goes well, JWST will start examining galaxies across the universe and planets orbiting stars across our Milky Way Galaxy in the summer of 2022. from NASA https://ift.tt/3qsVlZC

By Dennis Overbye and Joey Roulette from NYT Science https://ift.tt/3qsfvTy

The tail of a comet streams across this three degree wide telescopic field of view captured under dark Namibian skies on December 21. In outburst only a few days ago and just reaching naked eye visibility Comet Leonard (C/2021 A1) is this year's brightest comet. Binoculars will make the diffuse comet easier to spot though, close to the western horizon after sunset. Details revealed in the sharp image show the comet's coma with a greenish tinge, and follow the interaction of the comet's ion tail with magnetic fields in the solar wind. After passing closest to Earth on December 12 and Venus on December 18, Comet Leonard is heading toward perihelion, its closest approach to the Sun on January 3rd. Appearing in late December's beautiful evening skies after sunset, Comet Leonard has also become known as 2021's Christmas Comet. from NASA https://ift.tt/3qriJXl

By Dennis Overbye and Joey Roulette from NYT Science https://ift.tt/3Jdpd4X

The Crab Nebula is cataloged as M1, the first object on Charles Messier's famous 18th century list of things which are not comets. In fact, the Crab is now known to be a supernova remnant , debris from the death explosion of a massive star, witnessed by astronomers in the year 1054. This sharp, ground-based telescopic view combines broadband color data with narrowband data that tracks emission from ionized sulfur, hydrogen, and oxygen atoms to explore the tangled filaments within the still expanding cloud . One of the most exotic objects known to modern astronomers, the Crab Pulsar , a neutron star spinning 30 times a second, is visible as a bright spot near the nebula's 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 a mere 6,500 light-years away in the constellation Taurus . from NASA https://ift.tt/3enJ7vY

Are you still looking for that perfect holiday gift for an astronomer? If your night sky is dark and horizon clear enough, the Solar System may have done your shopping for you. Send them outside after sunset to see three planets and a comet. In this snapshot of the December solstice evening sky from the village of Kirazli, Turkey the brightest celestial beacon is Venus, close to the southwestern horizon at the right. Look left and up to find Saturn shining between clouds. Follow that line farther left and up to bright Jupiter, the Solar System's ruling gas giant. This year's surprise visitor to the inner Solar System, Comet Leonard (C/2021 A1), is near the horizon too. The comet is fainter but forms a nearly equilateral triangle with planets Venus and Saturn in this view. After a dramatic brightening in recent days the comet is just visible to the unaided eye, though a nice pair of binoculars is always a good idea . from NASA https://ift.tt/3pnZuyA

Birds don't fly this high. Airplanes don't go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on , nor could any human just a millennium ago . The launch of a rocket bound for space is an event that inspires awe and challenges description. Pictured here , a SpaceX Falcon 9 rocket lifted off from Kennedy Space Center , Florida earlier this month carrying the Imaging X-ray Polarimetry Explorer (IXPE). IXPE is scheduled to observe high-energy objects such as neutron stars , black holes, and the centers of distant galaxies to better determine the physics and geometries that create and control them. From a standing start, the 300,000+ kilogram rocket ship lifted IXPE up to circle the Earth , where the outside air is too thin to breathe. Rockets bound for space are now launched from somewhere on Earth every few days . from NASA https://ift.tt/3FjkhsT

By Ellen Barry from NYT Science https://ift.tt/3sm7mmk

Welcome to December's solstice, first day of winter in the north and summer for the southern hemisphere. Astronomical markers of the seasons, solstice and equinox dates are based on the Sun's place in its annual journey along the ecliptic , through planet Earth's sky. At this solstice , the Sun reaches its maximum southern declination of -23.5 degrees today at 15:59 UTC , while its right ascension coordinate on the celestial sphere is 18 hours. That puts the Sun in the constellation Sagittarius in a direction near the center of our Milky Way galaxy . In fact, if you could see today's Solstice Sun against faint background stars and nebulae (that's really hard to do , especially in the daytime ...) your view might look something like this composited panorama. To make it, images of our fair galaxy were taken under dark Namibia n night skies, then stitched together in a panoramic view. From a snapshot made on 2015 December 21 , the Sun was digitally overlayed a

This picture was supposed to feature a comet. Specifically, a series of images of the brightest comet of 2021 were being captured: Comet Leonard . But the universe had other plans. Within a fraction of a second, a meteor so bright it could be called a fireball streaked through just below the comet. And the meteor's flash was even more green than the comet's coma. The cause of the meteor's green was likely magnesium evaporating from the meteor's pebble-sized core, while the cause of the comet's green was likely diatomic carbon recently ejected from the comet's city-sized nucleus . The images were taken 10 days ago over the Sacramento River and Mt. Lassen in California , USA . The fireball was on the leading edge of this year's Geminid Meteor Shower -- which peaked a few days later. Comet Leonard is now fading after reaching naked-eye visibility last week -- but now is moving into southern skies . from NASA https://ift.tt/3pajwg0

By Jan Hoffman from NYT Science https://ift.tt/3spjPWx

It is not a coincidence that planets line up. That's because all of the planets orbit the Sun in (nearly) a single sheet called the plane of the ecliptic . When viewed from inside that plane -- as Earth dwellers are likely to do -- the planets all appear confined to a single band . It is a coincidence, though, when three of the brightest planets all appear in nearly the same direction. Such a coincidence was captured earlier this month. Featured above (right to left), Venus , Saturn , and Jupiter were all imaged together in a line just after sunset, from the San Fermo Hills , Bergamo , Italy . Joining the alignment are Earth's Moon , and the position of the more distant Uranus . Bands of clouds streak across the sky toward the setting Sun . As Comet Leonard fades, this planetary alignment -- absent the Moon -- should persist for the rest of the month. from NASA https://ift.tt/3si6nDv

The first identified compact galaxy group, Stephan's Quintet is featured in this eye-catching image constructed with data drawn from the extensive Hubble Legacy Archive . About 300 million light-years away, only four of these five galaxies are actually locked in a cosmic dance of repeated close encounters. The odd man out is easy to spot, though. The interacting galaxies, NGC 7319, 7318A, 7318B, and 7317 have an overall yellowish cast. They also tend to have distorted loops and tails , grown under the influence of disruptive gravitational tides . But the predominantly bluish galaxy, NGC 7320, is closer, just 40 million light-years distant, and isn't part of the interacting group. Stephan's Quintet lies within the boundaries of the high flying constellation Pegasus . At the estimated distance of the quartet of interacting galaxies, this field of view spans about 500,000 light-years. But moving just beyond this field, up and to the right, astronomers can identify another

An arid expanse of the Tengger Desert in north-central China, planet Earth fills the foreground of this starry scene. A widefield panoramic view, it was recorded shortly after moonset in the local predawn hours of December 14. Pictured in the still dark sky, stars of the northern winter hexagon surround a luminous Milky Way. Seen near the peak of the annual meteor shower , the startling flash of a bright Geminid fireball meteor was also captured on that night. Above the western horizon and just below bright star Capella, its dagger-like trail points back to the meteor shower's radiant in Gemini . Of course, the constellation Gemini is easy to spot. Its twin bright stars, bluish Castor and yellowish Pollux are near top center in the frame. from NASA https://ift.tt/3GQduat

Fireflies flash along a moonlit countryside in this scene taken on the night of December 13/14 from southern Uruguay, planet Earth. On that night meteors fell in the partly cloudy skies above during the annual Geminid meteor shower . Frames recorded over a period of 1.5 hours are aligned in the composite image made with the camera facing south. That direction was opposite the shower's radiant toward the north and so the Geminid meteor streaks appear to converge at an antiradiant below the southern horizon. The shower's apparent radiant (and antiradiant ) is just due to perspective though. As Earth sweeps through the dust trail of mysterious asteroid 3200 Phaethon , the dust grains that create the Geminid shower meteors are really moving along parallel tracks. They enter Earth's atmosphere traveling at about 22 kilometers per second. from NASA https://ift.tt/3ywEF7b

What does Comet Leonard look like from space? Today's featured image from Origin.Space 's Yangwang-1 space telescope shows not only the currently bright comet -- but several other space delights as well. Taken in optical and ultraviolet light, C/2021 A1 (Leonard) is visible with an extended tail near the image center as it appeared five days ago. The Earth is visible on the lower right, while layers of the Earth's atmosphere glow diagonally from the lower left to the upper right. The trails of two satellites can be seen in front of a myriad of distant stars that dot the background on the upper left. The faint bands of light running diagonally from the lower right to the upper left are auroras . Finally, the image also caught a meteor streaking just below the airglow . To see Comet Leonard yourself from the Earth's surface during the next few days, look toward the western horizon just after sunset or just before sunrise. from NASA https://ift.tt/3s76npT

By Dennis Overbye from NYT Science https://ift.tt/3m572Ey

To some, it may look like a beehive . In reality, the featured image from the Hubble Space Telescope captures a cosmic pillar of dust, over two- light years long, inside of which is Herbig-Haro 666 -- a young star emitting powerful jets. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula , shining in southern skies at a distance of about 7,500 light-years. The pillar 's layered outline are shaped by the winds and radiation of Carina's young, hot, massive stars, some of which are still forming inside the nebula. A dust-penetrating view in infrared light better shows the two, narrow, energetic jets blasting outward from a still hidden infant star. from NASA https://ift.tt/3dMtTA3

By Adam Mann from NYT Science https://ift.tt/3DTddlg

Comet Leonard is now visible to the unaided eye -- but just barely. Passing nearest to the Earth today, the comet is best seen this week soon after sunset, toward the west, low on the horizon. Currently best visible in the north, by late December the comet will best be seen from south of Earth's equator . The featured image of Comet C/2021 A1 (Leonard) was taken a week ago from California , USA . The deep exposure shows in great detail the comet's green gas coma and developing dust tail . The comet -- across our inner Solar System and only light-minutes away -- was captured passing nearly in front of globular star cluster M3 . In contrast, M3 is about 35,000 light- years away. In a week, Comet Leonard will pass unusually close to Venus , but will continue on and be at its closest to the Sun in early January. from NASA https://ift.tt/3DZFjvj

From this vantage point about three quarters of a mile from planet Earth's geographic South Pole, the December 4 eclipse of the Sun was seen as a partial eclipse. At maximum eclipse the New Moon blocked 90 percent of the solar disk. Of course, crews at the South Pole Telescope (left) and BICEP telescope (right) climbed to the roof of Amundsen-Scott station's Dark Sector Laboratory to watch. Centered near the local eclipse maximum, the composite timelapse view features an image of the Sun in cold antarctic skies taken every four minutes. Left to right along the roof line it also features the raised arms of Brandon Amat, Aman Chokshi, Cheng Zhang, James Bevington and Allen Forster. from NASA https://ift.tt/3EN2ASi

During polar day , in Arctic and Antarctic summer, the Sun stays above the horizon for periods of 24 hours or more. Recorded on December 4, this fisheye timelapse image tracks the Sun in multiple frames as it completes a circle in the summer sky above Union Glacier, Antarctica. Of course on that date, Union Glacier's sky did grow dark even though the Sun was above the horizon. Captured during the brief period of totality, an eclipsed Sun is at bottom center of the composite view. Near the edge of the total eclipse path across planet Earth, the Moon's shadow darkens the sky above . from NASA https://ift.tt/3lTPRWy

Few were able to stand in the Moon's shadow and watch the December 4 total eclipse of the Sun. Determined by celestial mechanics and not geographical boundaries, the narrow path of totality tracked across planet Earth's relatively inaccessible southernmost continent. Still, some enthusiastic and well-insulated eclipse chasers were rewarded with the dazzling spectacle in Antarctica's cold but clear skies. Taken just before the brief totality began, this image from a ground-based telescope inside the edge of the shadow path at Union Glacier catches a glimmer of sunlight near the top of the silhouetted lunar disk. Look closely for the pinkish solar prominences arcing above the Sun's limb. During totality, the magnificent solar corona , the Sun's outer atmosphere, made its much anticipated appearance, seen in the composite view streaming far from the Sun's edge. from NASA https://ift.tt/3pINQNO

Comet Hale-Bopp , the Great Comet of 1997, became much brighter than any surrounding stars. It was seen even over bright city lights . Away from city lights, however, it put on quite a spectacular show . Here Comet Hale-Bopp was photographed above Val Parola Pass in the Dolomite mountains surrounding Cortina d'Ampezzo , Italy . Comet Hale-Bopp 's blue ion tail , consisting of ions from the comet's nucleus , is pushed out by the solar wind . The white dust tail is composed of larger particles of dust from the nucleus driven by the pressure of sunlight, that orbit behind the comet . Comet Hale-Bopp (C/1995 O1) remained visible to the unaided eye for 18 months -- longer than any other comet in recorded history. The large comet is next expected to return around the year 4385 . This month, Comet Leonard is brightening and may soon become visible to the unaided eye. from NASA https://ift.tt/3lKdeld

Every time two massive black holes collide , a loud chirping sound is broadcast out into the universe in gravitational waves . Humanity has only had the technology to hear these unusual chirps for the past seven years, but since then we have heard about 90 -- during the first three observing runs. Featured above are the spectrograms -- plots of gravitational-wave frequency versus time -- of these 90 as detected by the giant detectors of LIGO (in the USA ), VIRGO (in Europe ), and KAGRA (in Japan ). The more energy received on Earth from a collision, the brighter it appears on the graphic. Among many science firsts , these gravitational-radiation chirps are giving humanity an unprecedented inventory of black holes and neutron stars , and a new way to measure the expansion rate of our universe. A fourth gravitational wave observing run with increased sensitivity is currently planned to begin in 2022 December. from NASA https://ift.tt/3rCin2y

What's that unusual spot on the Moon? It's the International Space Station . Using precise timing, the Earth-orbiting space platform was photographed in front of a partially lit gibbous Moon last month. The featured composite, taken from Payson , Arizona , USA last month, was intricately composed by combining, in part, many 1/2000-second images from a video of the ISS crossing the Moon . A close inspection of this unusually crisp ISS silhouette will reveal the outlines of numerous solar panels and trusses. The bright crater Tycho is visible on the upper left, as well as comparatively rough, light colored terrain known as highlands , and relatively smooth, dark colored areas known as maria . On-line tools can tell you when the International Space Station will be visible from your area. from NASA https://ift.tt/3prSMXn

Yesterday there was a total solar eclipse visible only at the end of the Earth. To capture the unusual phenomenon , airplanes took flight below the clouded seascape of Southern Ocean . The featured image shows one relatively spectacular capture where the bright spot is the outer corona of the Sun and the eclipsing Moon is seen as the dark spot in the center. A wing and engine of the airplane are visible across the left and bottom of the image, while another airplane observing the eclipse is visible on the far left. The dark area of the sky surrounding the eclipsed Sun is called a shadow cone . It is dark because you are looking down a long corridor of air shadowed by the Moon. A careful inspection of the eclipsed Sun will reveal the planet Mercury just to the right. The next total solar eclipse shadow will cross parts of Australia and Indonesia in April of 2023, while the one after that will cross North America in April of 2024 . from NASA https://ift.tt/32QFV9q

In this snapshot from November 18, the Full Moon was not far from Earth's shadow . In skies over Sicily the brightest lunar phase was eclipsed by passing clouds though. The full moonlight was dimmed and momentarily diffracted by small but similar sized water droplets near the edges of the high thin clouds. The resulting iridescence shines with colors like a lunar corona . On that night, the Full Moon was also seen close to the Pleiades star cluster appearing at the lower left of the iridescent cloud bank. The stars of the Seven Sisters were soon to share the sky with a darker, reddened lunar disk. from NASA https://ift.tt/3pjqheo

Sweeping through northern predawn skies, on November 24 Comet Leonard (C/2021 A1) was caught between two galaxies in this composite telescopic image . Sporting a greenish coma the comet's dusty tail seems to harpoon the heart of NGC 4631 (top) also known as the Whale Galaxy. Of course NGC 4631 and NGC 4656 (bottom, aka the Hockey Stick) are background galaxies some 25 million light-years away. On that date the comet was about 6 light-minutes from our fair planet. Its closest approach to Earth (and even closer approach to Venus ) still to come, Comet Leonard will grow brighter in December. Already a good object for binoculars and small telescopes, this comet will likely not return to the inner Solar System. Its perihelion, or closest approach to the Sun, will be on January 3, 2022. from NASA https://ift.tt/3pkHvrP

Grand spiral galaxies often seem to get all the glory, flaunting their young, bright, blue star clusters in beautiful, symmetric spiral arms. But small galaxies form stars too, like nearby NGC 6822, also known as Barnard's Galaxy . Beyond the rich starfields in the constellation Sagittarius, NGC 6822 is a mere 1.5 million light-years away, a member of our Local Group of galaxies. A dwarf irregular galaxy similar to the Small Magellanic Cloud , NGC 6822 is about 7,000 light-years across. Brighter foreground stars in our Milky Way have a spiky appearance. Behind them, Barnard's Galaxy is seen to be filled with young blue stars and mottled with the telltale pinkish hydrogen glow of star forming regions in this deep color composite image. from NASA https://ift.tt/3loEUM7

What causes a blue band to cross the Moon during a lunar eclipse? The blue band is real but usually quite hard to see. The featured HDR image of last week's lunar eclipse, however -- taken from Yancheng , China -- has been digitally processed to equalize the Moon's brightness and exaggerate the colors . The gray color of the bottom right is the Moon 's natural color, directly illuminated by sunlight. The upper left part of the Moon is not directly lit by the Sun since it is being eclipsed -- it in the Earth's shadow . It is faintly lit, though, by sunlight that has passed deep through Earth's atmosphere . This part of the Moon is red -- and called a blood Moon -- for the same reason that Earth's sunsets are red: because air scatters away more blue light than red. The unusual blue band is different -- its color is created by sunlight that has passed high through Earth's atmosphere, where red light is better absorbed by ozone than blue . A total eclip

What's that moving across the sky? A planet just a bit too faint to see with the unaided eye: Uranus . The gas giant out past Saturn was tracked earlier this month near opposition -- when it was closest to Earth and at its brightest. The featured video captured by the Bayfordbury Observatory in Hertfordshire , UK is a four-hour time-lapse showing Uranus with its four largest moons in tow: Titania , Oberon , Umbriel and Ariel . Uranus' apparent motion past background stars is really dominated by Earth's own orbital motion around our Sun. The cross seen centered on Uranus is called a diffraction spike and is caused by light diffracting around the four arms that hold one of the telescope 's mirrors in place. The rotation of the diffraction spikes is not caused by the rotation of Uranus but, essentially, by the rotation of the Earth . During the next few months Uranus itself will be visible with binoculars, but, as always, to see its moons will require a tele

What created the strange spiral structure on the upper left? No one is sure, although it is likely related to a star in a binary star system entering the planetary nebula phase, when its outer atmosphere is ejected. The huge spiral spans about a third of a light year across and, winding four or five complete turns , has a regularity that is without precedent. Given the expansion rate of the spiral gas, a new layer must appear about every 800 years, a close match to the time it takes for the two stars to orbit each other. The star system that created it is most commonly known as LL Pegasi , but also AFGL 3068 and IRAS 23166+1655. The featured image was taken in near- infrared light by the Hubble Space Telescope . Why the spiral glows is itself a mystery , with a leading hypothesis being illumination by light reflected from nearby stars. from NASA https://ift.tt/3D6qPJo

By Sabrina Imbler from NYT Science https://ift.tt/2Zu0B5P

This high cliff occurs not on a planet, not on a moon, but on a comet. It was discovered to be part of the dark nucleus of Comet Churyumov-Gerasimenko (CG) by Rosetta , a robotic spacecraft launched by ESA that rendezvoused with the Sun-orbiting comet in 2014. The ragged cliff, as featured here , was imaged by Rosetta in 2014. Although towering about one kilometer high, the low surface gravity of Comet CG would likely make it an accessible climb -- and even a jump from the cliff survivable. At the foot of the cliff is relatively smooth terrain dotted with boulders as large as 20 meters across. Data from Rosetta indicates that the ice in Comet CG has a significantly different deuterium fraction -- and hence likely a different origin -- than the water in Earth's oceans. Rosetta ended its mission with a controlled impact onto Comet CG in 2016. Comet CG has just completed another close approach to Earth and remains visible through a small telescope. from NASA https:/

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. M101 was also one of the original spiral nebulae observed by Lord Rosse's large 19th century telescope, the Leviathan of Parsontown. Assembled from 51 exposures recorded by the Hubble Space Telescope in the 20th and 21st centuries, with additional data from ground based telescopes, this mosaic spans about 40,000 light-years across the central region of M101 in one of the highest definition spiral galaxy portraits ever released from Hubble. The sharp image shows stunning features of the galaxy's face-on disk of stars and dust along with background galaxies, some visible right through M101 itself. Also known as the Pinwheel Galaxy, M101 lies within the boundaries of the northern constellation Ursa Major , about 25 million light-years

Rain clouds passed and the dome of the Lick Observatory's 36 inch Great Refractor opened on November 19. The historic telescope was pointed toward a partially eclipsed Moon. Illuminated by dim red lighting to preserve an astronomer's night vision, telescope controls, coordinate dials, and the refractor's 57 foot long barrel were captured in this high dynamic range image. Visible beyond the foreshortened barrel and dome slit, growing brighter after its almost total eclipse phase, the lunar disk created a colorful halo through lingering clouds. From the open dome, the view of the clearing sky above includes the Pleiades star cluster about 5 degrees from Moon and Earth's shadow . from NASA https://ift.tt/3r9xa4s

Shaped like a cone tapering into space, the Earth's dark central shadow or umbra has a circular cross-section. It's wider than the Moon at the distance of the Moon's orbit though. But during the lunar eclipse of November 18/19, part of the Moon remained just outside the umbral shadow. The successive pictures in this composite of 5 images from that almost total lunar eclipse were taken over a period of about 1.5 hours. The series is aligned to trace part of the cross-section's circular arc, with the central image at maximum eclipse. It shows a bright, thin sliver of the lunar disk still beyond the shadow's curved edge. Of course, even within the shadow the Moon's surface is not completely dark, reflecting the reddish hues of filtered sunlight scattered into the shadow by Earth's atmosphere. from NASA https://ift.tt/3xzpDNL

By Joey Roulette from NYT Science https://ift.tt/3DNi341

By Joey Roulette from NYT Science https://ift.tt/3xhUGNN

Have you ever seen the Pleiades star cluster? Even if you have, you probably have never seen it as large and clear as this. Perhaps the most famous star cluster on the sky, the bright stars of the Pleiades can be seen without binoculars from even the depths of a light-polluted city . With a long exposure from a dark location, though, the dust cloud surrounding the Pleiades star cluster becomes very evident. The featured exposure , taken from Florida, USA, covers a sky area several times the size of the full moon . Also known as the Seven Sisters and M45 , the Pleiades lies about 400 light years away toward the constellation of the Bull ( Taurus ). A common legend with a modern twist is that one of the brighter stars faded since the cluster was named, leaving only six of the sister stars visible to the unaided eye. The actual number of Pleiades stars visible, however, may be more or less than seven, depending on the darkness of the surrounding sky and the clarity of the obse

By Annie Roth from NYT Science https://ift.tt/32jcAUN

Why are the regions above sunspots so hot? Sunspot s themselves are a bit cooler than the surrounding solar surface because the magnetic fields that create them reduce convective heating. It is therefore unusual that regions overhead -- even much higher up in the Sun's corona -- can be hundreds of times hotter. To help find the cause, NASA directed the Earth-orbiting Nuclear Spectroscopic Telescope Array (NuSTAR) satellite to point its very sensitive X-ray telescope at the Sun. Featured here is the Sun in ultraviolet light, shown in a red hue as taken by the orbiting Solar Dynamics Observatory (SDO). Superimposed in false-colored green and blue is emission above sunspots detected by NuSTAR in different bands of high-energy X-rays , highlighting regions of extremely high temperature . Clues about the Sun's atmospheric heating mechanisms come from NuSTAR images like this and shed light on solar nanoflares and microflares as brief bursts of energy that may drive the