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How did we get here? We know that we live on a planet orbiting a star orbiting a galaxy , but how did all of this form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. Specifically, this featured video from the Illustris TNG collaboration tracks gas from the early universe ( redshift 12) until today ( redshift 0). As the simulation begins, ambient gas falls into and accumulates in a region of relatively high gravity . After a few billion years, a well-defined center materializes from a strange and fascinating cosmic dance . Gas blobs -- some representing small satellite galaxies -- continue to fall into and become absorbed by the rotating galaxy as the present epoch is reached and the video ends. For the Milky Way Galaxy , however, big mergers may not be over -- recent evidence indicates that our large spiral disk Galaxy will collide and coalesce with the slightly larger Andromeda spiral disk galaxy in the next...

Is this what will become of our Sun? Quite possibly. The first hint of our Sun 's future was discovered inadvertently in 1764 . At that time, Charles Messier was compiling a list of diffuse objects not to be confused with comets. The 27th object on Messier's list , now known as M27 or the Dumbbell Nebula, is a planetary nebula , one of the brightest planetary nebulae on the sky and visible with binoculars toward the constellation of the Fox ( Vulpecula ). It takes light about 1000 years to reach us from M27, featured here in colors emitted by sulfur (red), hydrogen (green) and oxygen (blue). We now know that in about 6 billion years, our Sun will shed its outer gases into a planetary nebula like M27, while its remaining center will become an X-ray hot white dwarf star. Understanding the physics and significance of M27 was well beyond 18th century science, though. Even today, many things remain mysterious about planetary nebulas , including how their intricate ...

What glows there? The answer depends: sea or sky? In the sea, the unusual blue glow is bioluminescence . Specifically, the glimmer arises from Noctiluca scintillans , single-celled plankton stimulated by the lapping waves. The plankton use their glow to startle and illuminate predators. This mid-February display on an island in the Maldives was so intense that the astrophotographer described it as a turquoise wonderland . In the sky, by contrast, are the more familiar glows of stars and nebula s. The white band rising from the artificially-illuminated green plants is created by billions of stars in the central disk of our Milky Way Galaxy . Also visible in the sky is the star cluster Omega Centauri , toward the left, and the famous Southern Cross asterism in the center. Red-glowing nebulas include the bright Carina Nebula , just right of center, and the expansive Gum Nebula on the upper right. from NASA https://ift.tt/6NVPSik

This asteroid has a moon. The robot spacecraft Galileo on route to Jupiter in 1993 encountered and photographed two asteroids during its long interplanetary voyage. The second minor planet it photographed, 243 Ida , was unexpectedly discovered to have a moon. The tiny moon, Dactyl , is only about 1.6 kilometers across and seen as a small dot on the right of the sharpened featured image . In contrast, the potato-shaped Ida is much larger, measuring about 60 kilometers long and 25 km wide. Dactyl is the first moon of an asteroid ever discovered -- now many asteroids are known to have moons . The names Ida and Dactyl are from Greek mythology . from NASA https://ift.tt/N4VZHiY

Gliding through the outer Solar System , in 1989 the Voyager 2 spacecraft looked toward the Sun to find this view of most distant planet Neptune and its moon Triton together in a crescent phase. The elegant image of ice-giant planet and largest moon was taken from behind just after Voyager's closest approach . It could not have been taken from Earth because the most distant planet never shows a crescent phase to sunward eyes . Heading for the heliopause and beyond , the spacecraft's parting vantage point also robs Neptune of its familiar blue hue . from NASA https://ift.tt/kD3Ifbj

Galaxies of the Virgo Cluster are scattered across this nearly 4 degree wide telescopic field of view . About 50 million light-years distant, the Virgo Cluster is the closest large galaxy cluster to our own local galaxy group. Prominent here are Virgo's bright elliptical galaxies Messier catalog , M87 at bottom center, and M84 and M86 (top to bottom) near top left. M84 and M86 are recognized as part of Markarian's Chain , a visually striking line-up of galaxies on the left side of this frame. Near the middle of the chain lies an intriguing interacting pair of galaxies, NGC 4438 and NGC 4435, known to some as Markarian's Eyes . Of course giant elliptical galaxy M87 dominates the Virgo cluster. It's the home of a super massive black hole, the first black hole ever imaged by planet Earth's Event Horizon Telescope . from NASA https://ift.tt/yT4GO6Q

The Cat's Eye Nebula (NGC 6543) is one of the best known planetary nebulae in the sky. Its more familiar outlines are seen in the brighter central region of the nebula in this impressive wide-angle view. But this wide and deep image combining data from two telescopes also reveals its extremely faint outer halo. At an estimated distance of 3,000 light-years, the faint outer halo is over 5 light-years across. Planetary nebulae have long been appreciated as a final phase in the life of a sun-like star. More recently, some planetary nebulae are found to have halos like this one, likely formed of material shrugged off during earlier episodes in the star's evolution. While the planetary nebula phase is thought to last for around 10,000 years, astronomers estimate the age of the outer filamentary portions of this halo to be 50,000 to 90,000 years. Visible on the right, some 50 million light-years beyond the watchful planetary nebula, lies spiral galaxy NGC 6552. from NASA ht...

By Oliver Whang from NYT Science https://ift.tt/APr9z8Z

Sometimes we witness the Moon moving directly in front of -- called occulting -- one of the planets in our Solar System . Earlier this month that planet was Jupiter. Captured here was the moment when Jupiter re-appeared from behind the surface of our Moon. The Moon was in its third quarter , two days before the dark New Moon . Now, our Moon is continuously half lit by the Sun, but when in its third quarter, relatively little of that half can be seen from the Earth . Pictured, the Moon itself was aligned behind the famous Lick Observatory in California , USA , on the summit of Mount Hamilton . Coincidentally , Lick enabled the discovery of a moon of Jupiter: Amalthea , the last visually detected moon of Jupiter after Galileo 's observations . from NASA https://ift.tt/qlRtbjM

By Jeanne Timmons from NYT Science https://ift.tt/PQkNn6g

By Jennie Erin Smith and Charlie Cordero from NYT Science https://ift.tt/pAd7bIh

Big storms are different on Jupiter. On Earth, huge hurricanes and colossal cyclones are centered on regions of low pressure, but on Jupiter, it is the high-pressure, anti-cyclone storms that are the largest. On Earth , large storms can last weeks, but on Jupiter they can last years. On Earth, large storms can be as large as a country, but on Jupiter, large storms can be as large as planet Earth. Both types of storms are known to exhibit light ning . The featured image of Jupiter's clouds was composed from images and data captured by the robotic Juno spacecraft as it swooped close to the massive planet in August 2020.  A swirling white oval is visible nearby, while numerous smaller cloud swirls extend into the distance.  On Jupiter, light-colored clouds are usually higher up than dark clouds. Despite their differences, studying storm clouds on distant Jupiter provides insights into storms and other weather patterns on familiar Earth .  from NASA https://if...

By Siobhan Roberts from NYT Science https://ift.tt/bG2ZUtI

A nearby star has exploded and humanity's telescopes are turning to monitor it. The supernova, dubbed SN 2023ifx , was discovered by Japanese astronomer Koichi Itagaki three days ago and subsequently located on automated images from the Zwicky Transient Facility two days earlier. SN 2023ifx occurred in the photogenic Pinwheel Galaxy M101 , which, being only about 21 million light years away, makes it the closest supernova seen in the past five years, the second closest in the past 10 years, and the second supernova found in M101 in the past 15 years. Rapid follow up observations already indicate that SN 2023ifx is a Type II supernova , an explosion that occurs after a massive star runs out of nuclear fuel and collapses. The featured image shows home spiral galaxy two days ago with the supernova highlighted, while the roll-over image shows the same galaxy a month before. SN 2023ifx will likely brighten and remain visible to telescopes for months. Studying such a close and y...

Is this an alien? Probably not, but of all the animals on Earth, the tardigrade might be the best candidate. That's because tardigrades are known to be able to go for decades without food or water, to survive temperatures from near absolute zero to well above the boiling point of water, to survive pressures from near zero to well above that on ocean floors , and to survive direct exposure to dangerous radiations . The far-ranging survivability of these extremophiles was tested in 2011 outside an orbiting space shuttle. Tardigrades are so durable partly because they can repair their own DNA and reduce their body water content to a few percent. Some of these miniature water-bears almost became extraterrestrials in 2011 when they were launched toward to the Martian moon Phobos , and again in 2021 when they were launched toward Earth's own moon, but the former launch failed, and the latter landing crashed. Tardigrades are more common than human s across most of the Ea...

Looping through the Jovian system in the late 1990s, the Galileo spacecraft recorded stunning views of Europa and uncovered evidence that the moon's icy surface likely hides a deep, global ocean. Galileo's Europa image data has been remastered here , with improved calibrations to produce a color image approximating what the human eye might see. Europa's long curving fractures hint at the subsurface liquid water . The tidal flexing the large moon experiences in its elliptical orbit around Jupiter supplies the energy to keep the ocean liquid. But more tantalizing is the possibility that even in the absence of sunlight that process could also supply the energy to support life, making Europa one of the best places to look for life beyond Earth. What kind of life could thrive in a deep, dark, subsurface ocean? Consider planet Earth's own extreme shrimp . from NASA https://ift.tt/IhXG39u

A bright spiral galaxy of the northern sky, Messier 63 is nearby, about 30 million light-years distant toward the loyal constellation Canes Venatici. Also cataloged as NGC 5055, the majestic island universe is nearly 100,000 light-years across, about the size of our own Milky Way . Its bright core and majestic spiral arms lend the galaxy its popular name, The Sunflower Galaxy. This exceptionally deep exposure also follows faint, arcing star streams far into the galaxy's halo. Extending nearly 180,000 light-years from the galactic center, the star streams are likely remnants of tidally disrupted satellites of M63. Other satellite galaxies of M63 can be spotted in the remarkable wide-field image , including faint dwarf galaxies , which could contribute to M63's star streams in the next few billion years. from NASA https://ift.tt/FGV9M0Y

By April Rubin from NYT Science https://ift.tt/UHc6b4w

Made with narrowband filters, this cosmic snapshot covers a field of view about the size of the full Moon within the boundaries of the constellation Cygnus. It highlights the bright edge of a ring-like nebula traced by the glow of ionized sulfur, hydrogen, and oxygen gas. Embedded in the region's interstellar clouds of gas and dust, the complex, glowing arcs are sections of bubbles or shells of material swept up by the wind from Wolf-Rayet star WR 134, brightest star near the center of the frame. Distance estimates put WR 134 about 6,000 light-years away, making the frame over 50 light-years across. Shedding their outer envelopes in powerful stellar winds, massive Wolf-Rayet stars have burned through their nuclear fuel at a prodigious rate and end this final phase of massive star evolution in a spectacular supernova explosion. The stellar winds and final supernovae enrich the interstellar material with heavy elements to be incorporated in future generations of stars . fr...

By Carl Zimmer from NYT Science https://ift.tt/hqdVl3B

Why would a small part of the Sun appear slightly dark? Visible is a close-up picture of sunspot s, depressions on the Sun's surface that are slightly cooler and less bright than the rest of the Sun. The Sun's complex magnetic field creates these cool regions by inhibiting hot material from entering the spots. Sunspots can be larger than the Earth and typically last for about a week. Part of active region AR 3297 crossing the Sun in early May, the large lower sunspot is spanned by an impressive light bridge of hot and suspended solar gas. This high-resolution picture also shows clearly that the Sun's surface is a bubbling carpet of separate cells of hot gas. These cells are known as granules . A solar granule is about 1000 kilometers across and lasts for only about 15 minutes. from NASA https://ift.tt/m8hK2wr

Most photographs don't adequately portray the magnificence of the Sun 's corona. Seeing the corona first-hand during a total solar eclipse is unparalleled . The human eye can adapt to see coronal features and extent that average cameras usually cannot. Welcome, however, to the digital age. The featured image digitally combined short and long exposures taken in Exmouth , Australia that were processed to highlight faint and extended features in the corona during the total solar eclipse that occurred in April of 2023 . Clearly visible are intricate layers and glowing caustics of an ever changing mixture of hot gas and magnetic fields in the Sun's corona. Looping prominences appear bright pink just past the Sun's edge . Images taken seconds before and after the total eclipse show glimpses of the background Sun known as Baily's Beads and diamond ring effect. The next total solar eclipse will cross North America in April of 2024 . from NASA https://ift.t...

By Lauren McCarthy from NYT Science https://ift.tt/gazYdyt

By Elizabeth Anne Brown from NYT Science https://ift.tt/Ns4Jbig

From afar, the whole thing looks like an eagle . A closer look at the Eagle Nebula , however, shows the bright region is actually a window into the center of a larger dark shell of dust . Through this window, a brightly-lit workshop appears where a whole open cluster of stars is being formed. In this cavity, tall pillars and round globules of dark dust and cold molecular gas remain where stars are still forming. Already visible are several young bright blue stars whose light and winds are burning away and pushing back the remaining filaments and walls of gas and dust. The Eagle emission nebula , tagged M16, lies about 6500 light years away, spans about 20 light-years, and is visible with binoculars toward the constellation of the Serpent ( Serpens ). This picture involved long and deep exposures and combined three specific emitted colors emitted by sulfur (colored as yellow), hydrogen (red), and oxygen (blue). from NASA https://ift.tt/gVHPpEY

What would it be like to fly free in space? At about 100 meters from the cargo bay of the space shuttle Challenger , Bruce McCandless II was living the dream -- floating farther out than anyone had ever been before. Guided by a Manned Maneuvering Unit (MMU), astronaut McCandless, pictured , was floating free in space. During Space Shuttle mission 41-B in 1984 , McCandless and fellow NASA astronaut Robert Stewart were the first to experience such an "un tether ed space walk ". The MMU worked by shooting jets of nitrogen and was used to help deploy and retrieve satellites . With a mass over 140 kilograms, an MMU is heavy on Earth , but, like everything, is weightless when drifting in orbit. The MMU was later replaced with the SAFER backpack propulsion unit. from NASA https://ift.tt/bEvH9qn

Our fair planet sports a curved, sunlit crescent against the black backdrop of space in this stunning photograph. From the unfamiliar perspective, the Earth is small and, like a telescopic image of a distant planet, the entire horizon is completely within the field of view. Enjoyed by crews on board the International Space Station, only much closer views of the planet are possible from low Earth orbit. Orbiting the planet once every 90 minutes, a spectacle of clouds, oceans, and continents scrolls beneath them with the partial arc of the planet's edge in the distance. But this digitally restored image presents a view so far only achieved by 24 humans, Apollo astronauts who traveled to the Moon and back again between 1968 and 1972. The original photograph, AS17-152-23420 , was taken by the homeward bound crew of Apollo 17 , on December 17, 1972. For now it is the last picture of Earth from this planetary perspective taken by human hands . from NASA https://ift.tt/BCFMZVs ...

By Darren Incorvaia from NYT Science https://ift.tt/14eVtZR

Grains of cosmic dust streaked through night skies in early May. Swept up as planet Earth plowed through the debris streams left behind by periodic Comet Halley , the annual meteor shower is known as the Eta Aquarids. This year, the Eta Aquarids peak was visually hampered by May's bright Full Moon, though. But early morning hours surrounding last May's shower of Halley dust were free of moonlight interference. In exposures recorded between April 28 and May 8 in 2022, this composited image shows nearly 90 Eta Aquarid meteors streaking from the shower's radiant in Aquarius over San Pedro de Atacama, Chile. The central Milky Way arcs above in the southern hemisphere's predawn skies. The faint band of light rising from the horizon is Zodiacal light, caused by dust scattering sunlight near our Solar System's ecliptic plane. Along the ecliptic and entrained in the Zodiacal glow are the bright planets Venus, Jupiter, Mars, and Saturn. Of course Mars itself has recent...

Fomalhaut is a bright star, a 25 light-year voyage from planet Earth in the direction of the constellation Piscis Austrinus . Astronomers first noticed Fomalhaut's excess infrared emission in the 1980s. Space and ground-based telescopes have since identified the infrared emission's source as a disk of dusty debris surrounding the hot, young star related to the ongoing formation of a planetary system. But this sharp infrared image from the James Webb Space Telescope's MIRI camera reveals details of Fomalhaut's debris disk never before seen, including a large dust cloud in the outer ring that is possible evidence for colliding bodies, and an inner dust disk and gap likely shaped and maintained by embedded but unseen planets. An image scale bar in au or astronomical units, the average Earth-Sun distance, appears at the lower left. Fomalhaut's outer circumstellar dust ring lies at about twice the distance of our own Solar System's Kuiper Belt of small icy bo...

By Elie Dolgin from NYT Science https://ift.tt/f3jy2ix

For ten years the stargazer dreamed of taking a picture like this. The dreamer knew that the White Desert National Park in Egypt 's Western Desert is a picturesque place hosting numerous chalk formations sculpted into surreal structures by a sandy wind. The dreamer knew that the sky above could be impressively dark on a clear moonless night, showing highlights such as the central band of our Milky Way Galaxy in impressive color and detail. So the dreamer invited an even more experienced astrophotographer to spend three weeks together in the desert and plan the composite images that needed to be taken and processed to create the dream image. Over three days in mid-March, the base images were taken, all with the same camera and from the same location. The impressive result is featured here, with the dreamer -- proudly wearing a traditional Bedouin galabyia -- pictured in the foreground. from NASA https://ift.tt/vOe2JTS

Can you find two Earth shadows in today's image? It's a bit tricky. To find the first shadow, observe that the top part of the atmosphere appears pink and the lower part appears blue. This is because the top half is exposed to direct sunlight , while the lower part is not. The purple area in between is known as the Belt of Venus , even though Venus can only appear on the other side of the sky, near the Sun . The blue color of the lower atmosphere is caused by the Earth blocking sunlight, creating Earth shadow number 1. Now, where is the second Earth shadow? Take a look at the Moon . Do you notice something unusual about the lower left part? That area appears unusually dark because it is in the shadow of the Earth , creating Earth shadow number 2. To be precise, the Moon was captured during a lunar eclipse . This carefully timed image was taken in Sampieri , Sicily , Italy , in July 2018. from NASA https://ift.tt/cdxz1PS

If not perfect, then this spiral galaxy is at least one of the most photogenic. An island universe containing billions of stars and situated about 40 million light-years away toward the constellation of the Dolphinfish ( Dorado ), NGC 1566 presents a gorgeous face-on view . Classified as a grand design spiral, NGC 1566 shows two prominent and graceful spiral arms that are traced by bright blue star clusters and dark cosmic dust lanes. Numerous Hubble Space Telescope images of NGC 1566 have been taken to study star formation , supernovas , and the spiral's unusually active center. Some of these images, stored online in the Hubble Legacy Archive , were freely downloaded, combined, and digitally processed by an industrious amateur to create the featured image. NGC 1566's flaring center makes the spiral one of the closest and brightest Seyfert galaxies , likely housing a central supermassive black hole wreaking havoc on surrounding stars and gas . from NASA https://i...

Will our Sun look like this one day? The Helix Nebula is one of brightest and closest examples of a planetary nebula , a gas cloud created at the end of the life of a Sun-like star. The outer gasses of the star expelled into space appear from our vantage point as if we are looking down a helix . The remnant central stellar core, destined to become a white dwarf star , glows in light so energetic it causes the previously expelled gas to fluoresce . The Helix Nebula , given a technical designation of NGC 7293 , lies about 700 light-years away towards the constellation of the Water Bearer ( Aquarius ) and spans about 2.5 light-years. The featured picture was taken with the Canada-France-Hawaii Telescope (CFHT) located atop a dormant volcano in Hawaii , USA . A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin . from NASA https://ift.tt/2BxXCGV

Transformed into the petals of a flower, 16 exposures show the passage of day into night in this creative timelapse skyscape . Start at the top and move counterclockwise to follow consecutive moments as the twilight sky turns an ever darker blue and night blossoms. Each exposure was recorded on the evening of April 22 , calculated to maintain a consistent balance of light and color. Close to the western horizon on that date, a crescent Moon and Venus are the two brightest celestial beacons . Petal to petal the pair spiral closer to the flower's center. In silhouette around the center of the twilight flower are Sicily's megalithic rocks of Argimusco . from NASA https://ift.tt/lUfEiJj

By April Rubin from NYT Science https://ift.tt/RwVCiuQ

By James Crugnale from NYT Science https://ift.tt/6smDEQv

Shackleton crater lies at the lunar south pole . Peaks along the 21 kilometer diameter are in sunlight, but Shackleton's floor is in dark permanent shadow . Still, this image of the shadowed rim wall and floor of Shackleton crater was captured from NASA's ShadowCam , an instrument on board the Korea Pathfinder Lunar Orbiter (KPLO) launched in August 2022. About 200 times more sensitive than, for example, the Lunar Reconnaissance Orbiter's Narrow Angle Camera, ShadowCam was designed image the permanently shadowed regions of the lunar surface. Avoiding direct sunlight, those regions are expected to be reservoirs of water-ice and other volatiles deposited by ancient cometary impacts and useful to future Moon missions. Of course, the permanently shadowed regions are still illuminated by reflections of sunlight from nearby lunar terrain . In this stunningly detailed ShadowCam image , an arrow marks the track made by a single boulder rolling down Shackleton crater's wall. T...

By Dennis Overbye from NYT Science https://ift.tt/VgnN5sv

Bright elliptical galaxy Messier 87 (M87) is home to the supermassive black hole captured in 2017 by planet Earth's Event Horizon Telescope in the first ever image of a black hole. Giant of the Virgo galaxy cluster about 55 million light-years away, M87 is the large galaxy rendered in blue hues in this infrared image from the Spitzer Space telescope . Though M87 appears mostly featureless and cloud-like, the Spitzer image does record details of relativistic jets blasting from the galaxy's central region. Shown in the inset at top right, the jets themselves span thousands of light-years. The brighter jet seen on the right is approaching and close to our line of sight. Opposite, the shock created by the otherwise unseen receding jet lights up a fainter arc of material. Inset at bottom right, the historic black hole image is shown in context, at the center of giant galaxy and relativistic jets. Completely unresolved in the Spitzer image, the supermassive black hole surrounde...

By Becky Ferreira from NYT Science https://ift.tt/rJRMIPG

Galaxies are fascinating. In galaxies , gravity alone holds together massive collections of stars, dust, interstellar gas, stellar remnants and dark matter. Pictured is NGC 5128, better known as Centaurus A. Cen A is the fifth brightest galaxy on the sky and is located at a distance of about 12 million light years from Earth. The warped shape of Cen A is the result of a merger between an elliptical and a spiral galaxy. Its active galactic nucleus harbors a supermassive black hole that is about 55 million times more massive than our Sun. This central black hole ejects a fast jet visible in both radio and X-ray light. Filaments of the jet are visible in red in the upper left. New observations by the Event Horizon Telescope have revealed a brightening of the jet only towards its edges -- but for reasons that are currently unknown and an active topic of research. from NASA https://ift.tt/0KJtebd

By Franz Lidz from NYT Science https://ift.tt/bHPM6zu

Why are there so many flat rocks on Mars? Some views of plains and hills on Mars show many rocks that are unusually flat when compared to rocks on Earth. One reason for this is a process that is common to both Mars and Earth: erosion . The carbon-dioxide wind on Mars can act like sandpaper when it blows around gritty Martian sand . This sand can create differential erosion, smoothing over some rocks , while wearing down the tops of other long-exposed stones. The featured image capturing several hills covered with flat-topped rocks was taken last month by NASA's Curiosity Rover on Mars. This robotic rover has now been rolling across Mars for ten years and has helped uncover many details of the wet and windy past of Earth's planetary neighbor. After taking this and other images , Curiosity carefully navigated stones and slippery sand to climb up Marker Band Valley . from NASA https://ift.tt/alt9fdR

The Great Carina Nebula is home to strange stars and iconic nebulas. Named for its home constellation , the huge star-forming region is larger and brighter than the Great Orion Nebula but less well known because it is so far south -- and because so much of humanity lives so far north . The featured image shows in great detail the northernmost part of the Carina Nebula . On the bottom left is the Gabriela Mistral Nebula consisting of an emission nebula of glowing gas (IC 2599) surrounding the small open cluster of stars ( NGC 3324 ). Above the image center is the larger star cluster NGC 3293 , while to its right is the emission nebula Loden 153. The most famous occupant of the Carina Nebula , however, is not shown. Off the image to the lower right is the bright, erratic, and doomed star known as Eta Carinae -- a star once one of the brightest stars in the sky and now predicted to explode in a supernova sometime in the next few million years. from NASA https://ift.tt/sX401Y...

By Kenneth Chang from NYT Science https://ift.tt/3FKYJm8

Although its colors may be subtle, Saturn's moon Helene is an enigma in any light. The moon was imaged in unprecedented detail in 2012 as the robotic Cassini spacecraft orbiting Saturn swooped to within a single Earth diameter of the diminutive moon . Although conventional craters and hills appear , the above image also shows terrain that appears unusually smooth and streaked. Planetary astronomers are inspecting these detailed images of Helene to glean clues about the origin and evolution of the 30-km across floating iceberg. Helene is also unusual because it circles Saturn just ahead of the large moon Dione , making it one of only four known Saturnian moons to occupy a gravitational well known as a stable Lagrange point . from NASA https://ift.tt/6ax5jTu

Along a narrow path that mostly avoided landfall, the shadow of the New Moon raced across planet Earth's southern hemisphere on April 20 to create a rare annular-total or hybrid solar eclipse . From the Indian Ocean off the coast of western Australia, ship-borne eclipse chasers were able to witness 62 seconds of totality though while anchored near the centerline of the total eclipse track. This ship-borne image of the eclipse captures the active Sun's magnificent outer atmosphere or solar corona streaming into space . A composite of 11 exposures ranging from 1/2000 to 1/2 second, it records an extended range of brightness to follow details of the corona not quite visible to the eye during the total eclipse phase. Of course eclipses tend to come in pairs. On May 5, the next Full Moon will just miss the dark inner part of Earth's shadow in a penumbral lunar eclipse. from NASA https://ift.tt/GxWKzIe

Like a ship plowing through cosmic seas, runaway star Alpha Camelopardalis has produced this graceful arcing bow wave or bow shock. The massive supergiant star moves at over 60 kilometers per second through space, compressing the interstellar material in its path. At the center of this nearly 6 degree wide view, Alpha Cam is about 25-30 times as massive as the Sun, 5 times hotter (30,000 kelvins), and over 500,000 times brighter. About 4,000 light-years away in the long-necked constellation Camelopardalis , the star also produces a strong stellar wind. Alpha Cam's bow shock stands off about 10 light-years from the star itself. What set this star in motion ? Astronomers have long thought that Alpha Cam was flung out of a nearby cluster of young hot stars due to gravitational interactions with other cluster members or perhaps by the supernova explosion of a massive companion star. from NASA https://ift.tt/ZBXJIzj