Apollo 14 Heads for Home

When leaving lunar orbit in February 1971, the crew of Apollo 14 watched this Earthrise from their command module Kittyhawk. With Earth's sunlit crescent just peaking over the lunar horizon, the cratered terrain in the foreground is along the lunar farside. Of course, while orbiting the Moon, the crew could watch Earth rise and set, but the Earth hung stationary in the sky over Fra Mauro Base, their landing site on the lunar surface. Rock samples brought back by the Apollo 14 mission included a 20 pound rock nicknamed Big Bertha, later determined to contain a likely fragment of a meteorite from planet Earth. via NASA https://ift.tt/2S7blzx

Goldilocks Zones and Stars

The Goldilocks zone is the habitable zone around a star where it's not too hot and not too cold for liquid water to exist on the surface of orbiting planets. This intriguing infographic includes relative sizes of those zones for yellow G stars like the Sun, along with orange K dwarf stars and red M dwarf stars, both cooler and fainter than the Sun. M stars (top) have small, close-in Goldilocks zones. They are also seen to live long (100 billion years or so) and are very abundant, making up about 73 percent of the stars in the Milky Way. Still, they have very active magnetic fields and may produce too much radiation harmful to life, with an estimated X-ray irradiance 400 times the quiet Sun. Sun-like G stars (bottom) have large Goldilocks zones and are relatively calm, with low amounts of harmful radiation. But they only account for 6 percent of Milky Way stars and are much shorter lived. In the search for habitable planets, K dwarf stars could be just right, though. Not too rare they have 40 billion year lifetimes, much longer than the Sun. With a relatively wide habitable zone they produce only modest amounts of harmful radiation. These Goldilocks stars account for about 13 percent of the stars of the Milky Way. via NASA https://ift.tt/36HM1oX

NASA Day of Remembrance

Amy Resnik touches the Space Shuttle Challenger Memorial after a wreath laying ceremony as part of NASA’s Day of Remembrance, Thursday, Jan. 30, 2020, at Arlington National Cemetery. via NASA https://ift.tt/2Ocv1Rg

Luca Parmitano Works to Repair the Alpha Magnetic Spectrometer

Astronaut and station commander Luca Parmitano is tethered to the International Space Station while finalizing thermal repairs on the AMS. via NASA https://ift.tt/37HsQwP

Two Custers and a Comet

This lovely starfield spans some four full moons (about 2 degrees) across the heroic northern constellation of Perseus. In telescopic exposures made during the nights of January 24, 26, and 28 it holds the famous pair of open or galactic star clusters h and Chi Persei with comet PanSTARRS (C/2017 T2) captured each night as it swept left to right across the field of view. Also cataloged as NGC 869 (right) and NGC 884, both star clusters are about 7,000 light-years away and contain stars much younger and hotter than the Sun. Separated by only a few hundred light-years, the clusters are both 13 million years young based on the ages of their individual stars, evidence that they were likely a product of the same star-forming region. Discovered in 2017 while still beyond the orbit of Saturn, Comet PanSTARRs is a new visitor to the inner solar system and just over 13 light-minutes from planet Earth. Always a rewarding sight in binoculars, the Double Cluster is even visible to the unaided eye from dark locations. C/2017 T2 could remain a telescopic comet though. One of the brightest comets anticipated in 2020 it makes its closest approach to the Sun in early May. via NASA https://ift.tt/2RZhkX0

Milky Way over Yellowstone

The Milky Way was not created by an evaporating lake. The pool of vivid blue water, about 10 meters across, is known as Silex Spring and is located in Yellowstone National Park in Wyoming, USA. Steam rises off the spring, heated by a magma chamber deep underneath known as the Yellowstone hotspot. The steam blurs the image of Venus, making it seem unusually large. Unrelated and far in the distance, the central band of our Milky Way Galaxy rises high overhead, a band lit by billions of stars. The featured picture is a 3-image panorama taken last August. If the Yellowstone hotspot causes another supervolcanic eruption as it did 640,000 years ago, a large part of North America would be affected. via NASA https://ift.tt/310DFaC

Chandra Spots a Mega-Cluster of Galaxies in the Making

Astronomers using data from NASA's Chandra X-ray Observatory and other telescopes have put together a detailed map of a rare collision between four galaxy clusters. via NASA https://ift.tt/32Upgx7

Star Formation in the Tadpole Nebula

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. via NASA https://ift.tt/311nmus

Spitzer Observes TRAPPIST-1

Spitzer Space Telescope, one of agency’s great observatories, one of Spitzer's great discoveries was that of the TRAPPIST-1 star, an ultra-cool dwarf, which has seven Earth-size planets orbiting it. via NASA https://ift.tt/2U23ciq

Comet CG Evaporates

Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. One of the best images of emerging jets is shown in the featured picture, taken in 2015 by ESA's robotic Rosetta spacecraft that orbited Comet 67P/Churyumov-Gerasimenko (Comet CG) from 2014 to 2016. The picture shows plumes of gas and dust escaping numerous places from Comet CG's nucleus as it neared the Sun and heated up. The comet has two prominent lobes, the larger one spanning about 4 kilometers, and a smaller 2.5-kilometer lobe connected by a narrow neck. Analyses indicate that evaporation must be taking place well inside the comet's surface to create the jets of dust and ice that we see emitted through the surface. Comet CG (also known as Comet 67P) loses in jets about a meter of radius during each of its 6.44-year orbits around the Sun, a rate at which will completely destroy the comet in only thousands of years. In 2016, Rosetta's mission ended with a controlled impact onto Comet CG's surface. via NASA https://ift.tt/2RMSedO

Hills Ridges and Tracks on Mars

Sometimes, even rovers on Mars stop to admire the scenery. Just late last November the Curiosity rover on Mars paused to photograph its impressive surroundings. One thing to admire, straight ahead, was Central Butte, an unusual flat hill studied by Curiosity just a few days before this image was taken. To its right was distant Mount Sharp, the five-kilometer central peak of entire Gale crater, the interior of which Curiosity is exploring. Mount Sharp, covered in sulfates, appears quite bright in this colorized, red-filtered image. To the far left, shrouded in a very dark shadow, was the south slope of Vera Rubin ridge, an elevation explored previously by Curiosity. Between the ridge and butte were tracks left by Curiosity's wheels as they rolled forward, out of the scene. In the image foreground is, of course, humanity's current eyes on Mars: the complex robotic rover Curiosity itself. Later this year, if all goes well, NASA will have another rover -- and more eyes -- on Mars. Today you can help determine the name of this rover yourself, but tomorrow is the last day to cast your vote. via NASA https://ift.tt/37ru2UN

Rubin s Galaxy

In this Hubble Space Telescope image the bright, spiky stars lie in the foreground toward the heroic northern constellation Perseus and well within our own Milky Way galaxy. In sharp focus beyond is UGC 2885, a giant spiral galaxy about 232 million light-years distant. Some 800,000 light-years across compared to the Milky Way's diameter of 100,000 light-years or so, it has around 1 trillion stars. That's about 10 times as many stars as the Milky Way. Part of a current investigation to understand how galaxies can grow to such enormous sizes, UGC 2885 was also part of astronomer Vera Rubin's pioneering study of the rotation of spiral galaxies. Her work was the first to convincingly demonstrate the dominating presence of dark matter in our universe. via NASA https://ift.tt/30UeOVP

Setting the Stage for Artemis Testing

All eyes are on south Mississippi with this month’s delivery and installation of NASA’s Space Launch System. via NASA https://ift.tt/2NW8Mid

Into the Shadow

On January 21, 2019 moonwatchers on planet Earth saw a total lunar eclipse. In 35 frames this composite image follows the Moon that night as it crossed into Earth's dark umbral shadow. Taken 3 minutes apart, they almost melt together in a continuous screen that captures the dark colors within the shadow itself and the northern curve of the shadow's edge. Sunlight scattered by the atmosphere into the shadow causes the lunar surface to appear reddened during totality (left), but close to the umbra's edge, the limb of the eclipsed Moon shows a remarkable blue hue. The blue eclipsed moonlight originates as rays of sunlight pass through layers high in Earth's upper stratosphere, colored by ozone that scatters red light and transmits blue. The Moon's next crossing into Earth's umbral shadow, will be on May 26, 2021. via NASA https://ift.tt/2vliLaJ

Globular Star Cluster NGC 6752

Some 13,000 light-years away toward the southern constellation Pavo, the globular star cluster NGC 6752 roams the halo of our Milky Way galaxy. Over 10 billion years old, NGC 6752 follows clusters Omega Centauri and 47 Tucanae as the third brightest globular in planet Earth's night sky. It holds over 100 thousand stars in a sphere about 100 light-years in diameter. Telescopic explorations of the NGC 6752 have found that a remarkable fraction of the stars near the cluster's core, are multiple star systems. They also reveal the presence of blue straggle stars, stars which appear to be too young and massive to exist in a cluster whose stars are all expected to be at least twice as old as the Sun. The blue stragglers are thought to be formed by star mergers and collisions in the dense stellar environment at the cluster's core. This sharp color composite also features the cluster's ancient red giant stars in yellowish hues. (Note: The bright, spiky blue star at 11 o'clock from the cluster center is a foreground star along the line-of-sight to NGC 6752) via NASA https://ift.tt/37iwi0A

Martin Luther King Day of Service at NASA Headquarters

The Amidon-Bowen Elementary School choir performs at the MLK Day of Service. via NASA https://ift.tt/2RhxWdr

The Hyades Star Cluster

It is the closest cluster of stars to the Sun. The Hyades open cluster is bright enough to have been remarked on even thousands of years ago, yet is not as bright or compact as the nearby Pleiades (M45) star cluster. Pictured here is a particularly deep image of the Hyades which has brings out vivid star colors and faint coincidental nebulas. The brightest star in the field is yellow Aldebaran, the eye of the bull toward the constellation of Taurus. Aldebaran, at 65 light-years away, is now known to be unrelated to the Hyades cluster, which lies about 150 light-years away. The central Hyades stars are spread out over about 15 light-years. Formed about 625 million years ago, the Hyades likely shares a common origin with the Beehive cluster (M44), a naked-eye open star cluster toward the constellation of Cancer, based on M44's motion through space and remarkably similar age. via NASA https://ift.tt/3aryuoF

Liftoff of SpaceX's In-Flight Abort Test

SpaceX's Falcon 9 rocket lifts off from Launch Complex 39A at the Kennedy Space Center at 10:30 a.m. EST on Jan. 19, 2020. via NASA https://ift.tt/30FxNU8

Parker: Sounds of the Solar Wind

What does the solar wind sound like? A wind of fast moving particles blows out from our Sun, and although space transmits sound poorly, particle impact and variable-field data from NASA's near-Sun Parker Solar Probe is being translated into sound. The disarming audio track of the featured video recounts several of these reverberations, including spooky-sounding Langmuir Waves (heard first), hurricane-sounding Whistler Mode Waves (heard next), and hard-to-describe Dispersive Chirping Waves (heard last). Also impressive is the video's time-lapse visual track which shows Parker's view to the side of its sun shield, and where the planets Earth, Jupiter, Mercury and Venus appear in succession, interspersed with bursts of powerful cosmic rays impacting the imager. The nature of the solar wind near Mercury is surprisingly different from near the Earth, and much study is underway to better understand the differences. via NASA https://ift.tt/38pEHiX

Quadrantid Meteors through Orion

Why are these meteor trails nearly parallel? Because they were all shed by the same space rock and so can be traced back to the same direction on the sky: the radiant of the Quadrantid Meteor Shower. This direction used to be toward the old constellation of Quadrans Muralis, hence the name Quadrantids, but when the International Astronomical Union formulated its list of modern constellations in 1922, this constellation did not make the list. Even though the meteors are now considered to originate from the recognized constellation of Bootes, the old name stuck. Regardless of the designation, every January the Earth moves through a dust stream and bits of this dust glow as meteors as they heat up in Earth's atmosphere. The featured image composite was taken on January 4 with a picturesque snowy Slovakian landscape in the foreground, and a deep-exposure sky prominently featuring the constellation Orion in the background. The red star Betelgeuse appears unusually dim -- its fading over the past few months is being tracked by astronomers. via NASA https://ift.tt/2G64LUf

M1: The Incredible Expanding Crab Nebula

Are your eyes good enough to see the Crab Nebula expand? The Crab Nebula is cataloged as M1, the first on Charles Messier's famous list of things which are not comets. In fact, the Crab is now known to be a supernova remnant, an expanding cloud of debris from the explosion of a massive star. The violent birth of the Crab was witnessed by astronomers in the year 1054. Roughly 10 light-years across today, the nebula is still expanding at a rate of over 1,000 kilometers per second. Over the past decade, its expansion has been documented in this stunning time-lapse movie. In each year from 2008 to 2017, an image was produced with the same telescope and camera from a remote observatory in Austria. Combined in the time-lapse movie, the 10 images represent 32 hours of total integration time. The sharp, processed frames even reveal the dynamic energetic emission within the incredible expanding Crab. The Crab Nebula lies about 6,500 light-years away in the constellation Taurus. via NASA https://ift.tt/2NEB296

An Almost Eclipse of the Moon

This composited series of images follows the Moon on January 10, the first Full Moon of 2020, in Hungarian skies. The lunar disk is in mid-eclipse at the center of the sequence though. It looks only slightly darker there as it passes through the light outer shadow or penumbra of planet Earth. In fact during this penumbral lunar eclipse the Moon almost crossed into the northern edge of Earth's dark central shadow or umbra. Subtle and hard to see, this penumbral lunar eclipse was the first of four lunar eclipses in 2020, all of which will be penumbral lunar eclipses. via NASA https://ift.tt/30vHmVH

Hubble Views Galaxy From Famous Catalog

This bright, somewhat blob-like object — seen in this image taken by the NASA/ESA Hubble Space Telescope — is a galaxy named NGC 1803. It is about 200 million light-years away, in the southern constellation of Pictor (the Painter’s Easel), and it was discovered in 1834 by astronomer John Herschel. via NASA https://ift.tt/2uckmi9

Apollo 17: A Stereo View from Lunar Orbit

Get out your red/blue glasses and check out this awesome stereo view of another world. The scene was recorded by Apollo 17 mission commander Eugene Cernan on December 11, 1972, one orbit before descending to land on the Moon. The stereo anaglyph was assembled from two photographs (AS17-147-22465, AS17-147-22466) captured from his vantage point on board the Lunar Module Challenger as he and Dr. Harrison Schmitt flew over Apollo 17's landing site in the Taurus-Littrow Valley. The broad, sunlit face of the mountain dubbed South Massif rises near the center of the frame, above the dark floor of Taurus-Littrow to its left. Beyond the mountains, toward the lunar limb, lies the Moon's Mare Serenitatis. Piloted by Ron Evans, the Command Module America is visible in orbit in the foreground against the South Massif's peak. via NASA https://ift.tt/2R0A1Kv

Cuatro Cienegas Basin, Mexico

In the northern Mexican state of Cohuilla lies the Cuatro Cienegas Basin. via NASA https://ift.tt/2QXHAl6

Astronauts Nick Hague and Anne McClain at the National Air and Space Museum

NASA astronauts Nick Hague and Anne McClain talk about their experiences onboard the International Space Station at the Smithsonian National Air and Space Museum in D.C. via NASA https://ift.tt/36YaXcC

NASA's Juno Spacecraft Has a Close Encounter with Jupiter

A multitude of swirling clouds in Jupiter's dynamic North North Temperate Belt is captured in this image from NASA's Juno spacecraft. via NASA https://ift.tt/2uOXA0m

Evidence of an Active Volcano on Venus

Are volcanoes still active on Venus? More volcanoes are known on Venus than Earth, but when Venusian volcanoes last erupted is not directly known. Evidence bolstering very recent volcanism on Venus has recently been uncovered, though, right here on Earth. Lab results showed that images of surface lava would become dim in the infrared in only months in the dense Venusian atmosphere, a dimming not seen in ESA's Venus Express images. Venus Express entered orbit around Venus in 2006 and remained in contact with Earth until 2014. Therefore, the infrared glow (shown in false-color red) recorded by Venus Express for Idunn Mons and featured here on a NASA Magellan image indicates that this volcano erupted very recently -- and is still active today. Understanding the volcanics of Venus might lead to insight about the volcanics on Earth, as well as elsewhere in our Solar System. via NASA https://ift.tt/2Npl8zk

A Desert Eclipse

A good place to see a ring-of-fire eclipse, it seemed, would be from a desert. In a desert, there should be relatively few obscuring clouds and trees. Therefore late last December a group of photographers traveled to the United Arab Emirates and Rub al-Khali, the largest continuous sand desert in world, to capture clear images of an unusual eclipse that would be passing over. A ring-of-fire eclipse is an annular eclipse that occurs when the Moon is far enough away on its elliptical orbit around the Earth so that it appears too small, angularly, to cover the entire Sun. At the maximum of an annular eclipse, the edges of the Sun can be seen all around the edges of the Moon, so that the Moon appears to be a dark spot that covers most -- but not all -- of the Sun. This particular eclipse, they knew, would peak soon after sunrise. After seeking out such a dry and barren place, it turned out that some of the most interesting eclipse images actually included a tree in the foreground, because, in addition to the sand dunes, the tree gave the surreal background a contrasting sense of normalcy, scale, and texture. via NASA https://ift.tt/3a38Q9t

Stars and Dust in Corona Australis

Cosmic dust clouds and young, energetic stars inhabit this telescopic vista, less than 500 light-years away toward the northern boundary of Corona Australis, the Southern Crown. The dust clouds effectively block light from more distant background stars in the Milky Way. But the striking complex of reflection nebulae cataloged as NGC 6726, 6727, and IC 4812 produce a characteristic blue color as light from the region's young hot stars is reflected by the cosmic dust. The dust also obscures from view stars still in the process of formation. At the left, smaller yellowish nebula NGC 6729 bends around young variable star R Coronae Australis. Just below it, glowing arcs and loops shocked by outflows from embedded newborn stars are identified as Herbig-Haro objects. On the sky this field of view spans about 1 degree. That corresponds to almost 9 light-years at the estimated distance of the nearby star forming region. via NASA https://ift.tt/30bvcB4

NGC 602 and Beyond

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. via NASA https://ift.tt/2QIFKEU

Welcoming NASA’s Newest Astronauts

NASA welcomed 11 new astronauts to its ranks Friday. via NASA https://ift.tt/2R4iArj

Nacreous Clouds over Sweden

Vivid and lustrous, wafting iridescent waves of color filled this mountain and skyscape near Tanndalen, Sweden on January 3. Known as nacreous clouds or mother-of-pearl clouds, they are rare. This northern winter season they have been making unforgettable appearances at high latitudes, though. A type of polar stratospheric cloud, they form when unusually cold temperatures in the usually cloudless lower stratosphere form ice crystals. Still sunlit at altitudes of around 15 to 25 kilometers the clouds can diffract sunlight after sunset and before the dawn. via NASA https://ift.tt/36LNsni

Perihelion to Aphelion

Perihelion for 2020, the point in Earth's elliptical orbit when it is closest to the Sun, occurred on January 5th. The distance from the Sun doesn't determine the seasons, though. Those are governed by the tilt of Earth's axis of rotation, so January is still winter in the north and summer in southern hemisphere. But it does mean that on January 5 the Sun was at its largest apparent size. This composite neatly compares two pictures of the Sun, both taken from planet Earth with the same telescope and camera. The left half was captured on the date of the 2020 perihelion. The right was recorded only a week before the July 4 date of the 2019 aphelion, the farthest point in Earth's orbit. Otherwise difficult to notice, the change in the Sun's apparent diameter between perihelion and aphelion amounts to a little over 3 percent. The 2020 perihelion and the preceding 2019 aphelion correspond to the closest and farthest perihelion and aphelion of the 21st century. via NASA https://ift.tt/2R3jDrq

What Happens When Planets Collide

This artist’s concept illustrates a catastrophic collision between two rocky exoplanets, turning both into dusty debris. via NASA https://ift.tt/2sY0Plt

Galaxies in the River

Large galaxies grow by eating small ones. Even our own galaxy engages in a sort of galactic cannibalism, absorbing small galaxies that are too close and are captured by the Milky Way's gravity. In fact, the practice is common in the universe and illustrated by this striking pair of interacting galaxies from the banks of the southern constellation Eridanus, The River. Located over 50 million light years away, the large, distorted spiral NGC 1532 is seen locked in a gravitational struggle with dwarf galaxy NGC 1531 (right of center), a struggle the smaller galaxy will eventually lose. Seen edge-on, spiral NGC 1532 spans about 100,000 light-years. Nicely detailed in this sharp image, the NGC 1532/1531 pair is thought to be similar to the well-studied system of face-on spiral and small companion known as M51. via NASA https://ift.tt/35taUEc

TESS Finds First Earth-Size Planet in the Habitable Zone

TOI 700 d is the first Earth-size habitable-zone planet discovered by TESS, NASA's Transiting Exoplanet Survey Satellite. via NASA https://ift.tt/2N4R2Rl

IC 405: The Flaming Star Nebula

Rippling dust and gas lanes give the Flaming Star Nebula its name. The orange and purple colors of the nebula are present in different regions and are created by different processes. The bright star AE Aurigae, visible toward the image left, is so hot it is blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, red light is frequently emitted (depicted here in orange). The purple region's color is a mix of this red light and blue light emitted by AE Aurigae but reflected to us by surrounding dust. The two regions are referred to as emission nebula and reflection nebula, respectively. Pictured here in the Hubble color palette, the Flaming Star Nebula, officially known as IC 405, lies about 1500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga). via NASA https://ift.tt/35yxjjj

The Next Step in Testing Rockets to Take Humanity to the Moon

On Jan.1, 2020, ​​NASA Administrator Jim Bridenstine tweeted: "Making progress! The massive @NASA_SLS core stage is moving to Building 110 at the Michoud Assembly Facility. via NASA https://ift.tt/2FrIjV8

Tumultuous Clouds of Jupiter

Some cloud patterns on Jupiter are quite complex. The featured tumultuous clouds were captured in May by NASA's robotic Juno spacecraft currently orbiting our Solar System's largest planet. The image was taken when Juno was only about 15,000 kilometers over Jupiter's cloud tops, so close that less than half of the giant planet is visible. The rough white clouds on the far right are high altitude clouds known as pop-up clouds. Juno's mission, now extended into 2021, is to study Jupiter in new ways. Among many other things, Juno has been measuring Jupiter's gravitational field, finding surprising evidence that Jupiter may be mostly a liquid. via NASA https://ift.tt/2QOjCHJ

A Starry Night of Iceland

On some nights, the sky is the best show in town. On this night, the sky was not only the best show in town, but a composite image of the sky won an international competition for landscape astrophotography. The featured winning image was taken in 2011 over Jökulsárlón, the largest glacial lake in Iceland. The photographer combined six exposures to capture not only two green auroral rings, but their reflections off the serene lake. Visible in the distant background sky is the band of our Milky Way Galaxy and the Andromeda galaxy. A powerful coronal mass ejection from the Sun caused auroras to be seen as far south as Wisconsin, USA. As the Sun progresses away from its current low in surface activity toward a solar maximum a few years away, many more spectacular images of aurora are expected. via NASA https://ift.tt/36nMi12

Aurora Slathers Up the Sky

Like salsa verde on your favorite burrito, a green aurora slathers up the sky in this 2017 June 25 snapshot from the International Space Station. 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 tantalizing glow is green at lower altitudes, but rarer reddish bands extend above the space station's horizon. The orbital scene was captured while passing over a point south and east of Australia, with stars above the horizon at the right belonging to the constellation Canis Major, Orion's big dog. Sirius, alpha star of Canis Major, is the brightest star near the Earth's limb. via NASA https://ift.tt/2FidGld

Hubble Sights Galaxy’s Celestial Sequins

This smattering of celestial sequins is a spiral galaxy named NGC 4455, located in the northern constellation of Coma Berenices (Berenice’s Hair). This might sound like an odd name for a constellation — and in fact it is somewhat unusual. It’s the only modern constellation named in honor of a real person from history: Queen Berenice II of Egypt. via NASA https://ift.tt/36mb4i1

Quadrantids over the Great Wall

Named for a forgotten constellation, the Quadrantid Meteor Shower is an annual event for planet Earth's northern hemisphere skygazers The shower's radiant on the sky lies within the old, astronomically obsolete constellation Quadrans Muralis. That location is not far from the Big Dipper, at the boundaries of the modern constellations Bootes and Draco. With the radiant out of the frame at the upper right, Quadrantid meteors streak through this night skyscape composed of digital frames recorded in the hours around the shower's peak on January 4, 2013. The last quarter moon illuminates rugged terrain and a section of the Great Wall in Hebei Province, China. A likely source of the dust stream that produces Quadrantid meteors was identified in 2003 as an asteroid. As usual, in 2020 the shower is expected to peak briefly on the night of January 3/4. Meteor fans in North America can anticpate a good show to celebrate the new year in moonless skies before tomorrow's dawn. via NASA https://ift.tt/2QnocxT

Glittering Lights of Earth As Seen From the Space Station

Stars glitter in the night sky above the Earth's atmospheric glow. via NASA https://ift.tt/2ZOTPmT

The Fainting of Betelgeuse

Begirt with many a blazing star, Orion the Hunter is one of the most recognizable constellations. In this night skyscape the Hunter's stars rise in the northern hemisphere's winter sky on December 30, 2019, tangled in bare trees near Newnan, Georgia, USA. Red super giant star Betelgeuse stands out in yellowish hues at Orion's shoulder left of center, but it no longer so strongly rivals the blue supergiant star Rigel at the Hunter's foot. In fact, skygazers around planet Earth can see a strikingly fainter Betelgeuse now, its brightness fading by more than half in the final months of 2019. Betelgeuse has long been known to be a variable star, changing its brightness in multiple cycles with approximate short and long term periods of hundreds of days to many years. The star is now close to its faintest since photometric measurements in 1926/27, likely due in part to a near coincidence in the minimum of short and long term cycles. Betelgeuse is also recognized as a nearby red supergiant star that will end its life in a core collapse supernova explosion sometime in the next 1,000 years, though that cosmic cataclysm will take place a safe 700 light-years or so from our fair planet. via NASA https://ift.tt/2SKKJpZ