omnianasa/nasa-apod-metadata huggingface dataset:
Chamaeleon Dark Nebulas (2024-07-22)
Sometimes the dark dust of interstellar space has an angular elegance.  Such is the case toward the far-south constellation of Chamaeleon. Normally too faint to see, dark dust is best known for blocking visible light from stars and galaxies behind it. In this 36.6-hour exposure, however, the dust is seen mostly in light of its own, with its strong red and near-infrared colors creating a brown hue. Contrastingly blue, the bright star Beta Chamaeleontis is visible on the upper right, with the dust that surrounds it preferentially reflecting blue light from its primarily blue-white color.  All of the pictured stars and dust occur in our own Milky Way Galaxy with one notable exception: the white spot just below Beta Chamaeleontis is the galaxy IC 3104 which lies far in the distance.  Interstellar dust is mostly created in the cool atmospheres of giant stars and dispersed into space by stellar light, stellar winds, and stellar explosions such as supernovas.
The Crab Nebula from Visible to X-Ray (2024-07-23)
What powers the Crab Nebula? A city-sized magnetized neutron star spinning around 30 times a second. Known as the Crab Pulsar, it is the bright spot in the center of the gaseous swirl at the nebula's core.  About 10 light-years across, the spectacular picture of the Crab Nebula (M1) frames a swirling central disk and complex filaments of surrounding and expanding glowing gas. The picture combines visible light from the Hubble Space Telescope in red and blue with X-ray light from the Chandra X-ray Observatory shown in white, and diffuse X-ray emission detected by Imaging X-ray Polarimetry Explorer (IXPE) in diffuse purple.  The central pulsar powers the Crab Nebula's emission and expansion by slightly slowing its spin rate, which drives out a wind of energetic electrons.  The featured image released today, the 25th Anniversary of the launch of NASA's flagship-class X-ray Observatory: Chandra.    Many Discoveries: Chandra Celebrates 25th Anniversary
Exaggerated Moon (2024-07-24)
Our Moon doesn't really have craters this big.  Earth's Moon, Luna, also doesn't naturally show this spikey texture, and its colors are more subtle. But this digital creation is based on reality.  The featured image is a digital composite of a good Moon image and surface height data taken from NASA's Lunar Orbiter Laser Altimeter (LOLA) mission -- and then exaggerated for educational understanding.  The digital enhancements, for example, accentuate lunar highlands and show more clearly craters that illustrate the tremendous bombardment our Moon has been through during its 4.6-billion-year history.  The dark areas, called maria, have fewer craters and were once seas of molten lava. Additionally, the image colors, although based on the moon's real composition, are changed and exaggerated.  Here, a blue hue indicates a region that is iron rich, while orange indicates a slight excess of aluminum.  Although the Moon has shown the same side to the Earth for billions of years, modern technology is allowing humanity to learn much more about it -- and how it affects the Earth.
NGC 7023: The Iris Nebula (2024-07-25)
These cosmic clouds have blossomed 1,300 light-years away in the fertile starfields of the constellation Cepheus. Called the Iris Nebula, NGC 7023 is not the only nebula to evoke the imagery of flowers. Still, this deep telescopic image shows off the Iris Nebula's range of colors and symmetries embedded in surrounding fields of interstellar dust. Within the Iris itself, dusty nebular material surrounds a hot, young star. The dominant color of the brighter reflection nebula is blue, characteristic of dust grains reflecting starlight. Central filaments of the reflection nebula glow with a faint reddish photoluminescence as some dust grains effectively convert the star's invisible ultraviolet radiation to visible red light. Infrared observations indicate that this nebula contains complex carbon molecules known as PAHs. The dusty blue petals of the Iris Nebula span about six light-years.
Facing NGC 6946 (2024-07-26)
From our vantage point in the Milky Way Galaxy, we see NGC 6946 face-on. The big, beautiful spiral galaxy is located just 20 million light-years away, behind a veil of foreground dust and stars in the high and far-off constellation Cepheus. In this sharp telescopic portrait, from the core outward the galaxy's colors change from the yellowish light of old stars in the center to young blue star clusters and reddish star forming regions along the loose, fragmented spiral arms. NGC 6946 is also bright in infrared light and rich in gas and dust, exhibiting a high star birth and death rate. In fact, since the early 20th century ten confirmed supernovae, the death explosions of massive stars, were discovered in NGC 6946. Nearly 40,000 light-years across, NGC 6946 is also known as the Fireworks Galaxy.
Saturn at the Moon's Edge (2024-07-27)
Saturn now rises before midnight in planet Earth's sky. On July 24, the naked-eye planet was in close conjunction, close on the sky, to a waning gibbous Moon. But from some locations on planet Earth the ringed gas giant was occulted, disappearing behind the Moon for about an hour from skies over parts of Asia and Africa. Because the Moon and bright planets wander through the sky near the ecliptic plane, such occultation events are not uncommon, but they can be dramatic. In this telescopic view from Nanjing, Jiangsu, China, Saturn is caught moments before its disappearance behind the lunar disk. The snapshot gives the illusion that Saturn hangs just above Glushko crater, a 43 kilometer diameter, young, ray crater near the Moon's western edge. Of course, the Moon is 400 thousand kilometers away, compared to Saturn's distance of 1.4 billion kilometers.
Milky Way over Uluru (2024-07-29)
What's happening above Uluru?  A United Nations World Heritage Site, Uluru  is an extraordinary 350-meter high mountain in central Australia that rises sharply from nearly flat surroundings. Composed of sandstone, Uluru has slowly formed over the past 300 million years as softer rock eroded away.  The Uluru region has been a home to humans for over 22,000 years. Recorded  last month, the starry sky above Uluru includes the central band of our Milky Way galaxy, complete with complex dark filaments of dust, bright red emission nebulas, and billions of stars.
Arp 142: Interacting Galaxies from Webb (2024-07-30)
To some, it looks like a penguin. But to people who study the universe, it is an interesting example of two big galaxies interacting. Just a few hundred million years ago, the upper NGC 2936 was likely a normal spiral galaxy: spinning, creating stars, and minding its own business.  Then it got too close to the massive elliptical galaxy NGC 2937, below, and took a dive.  Together known as Arp 142, they are featured in this new Webb infrared image, while a visible light Hubble image appears in comparison.  NGC 2936 is not only being deflected, but distorted, by this close gravitational interaction.  When massive galaxies pass near each other, gas is typically condensed from which new stars form.  A young group of stars appears as the nose of the penguin toward the right of the upper galaxy, while in the center of the spiral, bright stars together appear as an eye.  Before a billion years, the two galaxies will likely merge into one larger galaxy.   Explore Your Universe: Random APOD Generator
Leopard Spots on Martian Rocks (2024-07-31)
What is creating these unusual spots? Light-colored spots on Martian rocks, each surrounded by a dark border, were discovered earlier this month by NASA's Perseverance Rover currently exploring Mars.  Dubbed leopard spots because of their seemingly similarity to markings on famous Earth-bound predators, these curious patterns are being studied with the possibility they were created by ancient Martian life.  The pictured spots measure only millimeters across and were discovered on a larger rock named Cheyava Falls.  The exciting but unproven speculation is that long ago, microbes generated energy with chemical reactions that turned rock from red to white while leaving a dark ring, like some similarly appearing spots on Earth rocks. Although other non-biological explanations may ultimately prevail, speculation focusing on this potential biological origin is causing much intrigue.    New Mirror: APOD is now available from Brazil in Portuguese
Comet Olbers over Kunetice Castle (2024-08-01)
A visitor to the inner solar system every 70 years or so, Comet 13P/Olbers reached its most recent perihelion, or closest approach to the Sun, on June 30. Now on a return voyage to the distant Oort Cloud, the Halley-type comet is recorded here sweeping through northern summer night skies over historic Kunetice Castle, Czech Republic. The composite of tracked exposures for comet and sky, showing the comet's broad dust tail, brighter coma, and long ion tail buffeted by storms and winds from the Sun, and fixed exposures for foreground landscape was recorded on July 28. The comet is about 16 light-minutes beyond the castle and seen against faint background stars below the northern constellation Ursa Major. The hilltop castle dates to the 15th century, while Heinrich Olbers discovered the comet in 1815. Captured here low in northwestern skies just after sunset Comet Olbers, for now, offers skywatchers on planet Earth rewarding telescopic and binocular views. Comet 13P/Olbers' next perihelion passage will be in 2094.
Mars Passing By (2024-08-02)
As Mars wanders through Earth's night, it passes about 5 degrees south of the Pleiades star cluster in this composite astrophoto. The skyview was constructed from a series of images captured over a run of 16 consecutive clear nights beginning on July 12. Mars' march across the field of view begins at the far right, the planet's ruddy hue showing a nice contrast with the blue Pleiades stars. Moving much faster across the sky against the distant stars, the fourth planet from the Sun easily passes seventh planet Uranus. Red planet Mars and the ice giant world were in close conjunction, about 1/2 degree apart, on July 16. Continuing its rapid eastward trek, Mars has now left the sister stars and outer planet behind though, passing north of red giant star Aldebaran. Mars will come within about 1/3 degree of Jupiter in planet Earth's sky on August 14.
Glory and Fog Bow (2024-08-03)
On a road trip up Mount Uludağ in Bursa province, Turkey these motorcyclists found themselves above low clouds and fog in late June. With the bright Sun directly behind them, the view down the side of the great mountain revealed a beautiful, atmospheric glory and fog bow. Known to some as the heiligenschein or the Specter of the Brocken, a glory can also sometimes be seen from airplanes or even high buildings. It often appears to be a dark giant surrounded by a bright halo. Of course the dark giant is just the shadow of the observer (90MB video) cast opposite the Sun. The clouds and fog are composed of very small water droplets, smaller than rain drops, that refract and reflect sunlight to create the glory's colorful halo and this more extensive fog bow.
Milky Way Over Tunisia (2024-08-05)
That's no moon. On the ground, that's the Lars Homestead in Tunisia. And that's not just any galaxy. That's the central band of our own Milky Way galaxy. Last, that's not just any meteor. It is a bright fireball likely from last year's Perseids meteor shower. The featured image composite combines consecutive exposures taken by the same camera from the same location.  This year's Perseids peak during the coming weekend is expected to show the most meteors after the first quarter moon sets, near midnight.  To best experience a meteor shower, you should have clear and dark skies, a comfortable seat, and patience.
Storm Cloud Over Texas (2024-08-06)
What makes this storm cloud so colorful?  First, the cloud itself is composed of millions of tiny droplets of water and ice.  Its bottom is almost completely flat -- but this isn't unusual.  Bottom flatness in clouds is generally caused by air temperature dropping as you go up, and that above a specific height, water-saturated air condenses out water droplets.  The shape of the cloud middle is caused by a water-droplet-laden column of air being blown upward.  Most unusual, though, are the orange and yellow colors.  Both colors are caused by the cloud's water drops reflecting sunlight. The orange color in the cloud's middle and bottom sections are reflections of a nearly red sunset.  In contrast, the yellow color of the cloud's top results from reflection of light from a not-yet-setting Sun, where some -- but less -- blue light is being scattered away. Appearing to float above the plains in Texas, the featured impressive image of a dynamic cumulonimbus cloud was captured in 2021 while investigating a tornado.
Milky Way Behind Three Merlons (2024-08-07)
To some, they look like battlements, here protecting us against the center of the Milky Way. The Three Merlons, also called the Three Peaks of Lavaredo, stand tall today because they are made of dense dolomite rock which has better resisted erosion than surrounding softer rock. They formed about 250 million years ago and so are comparable in age with one of the great extinctions of life on Earth. A leading hypothesis is that this great extinction was triggered by an asteroid about 10-km across, larger in size than Mount Everest, impacting the Earth. Humans have gazed up at the stars in the Milky Way and beyond for centuries, making these battlefield-like formations, based in the Sexten Dolomites, a popular place for current and ancient astronomers.
Periodic Comet Swift-Tuttle (2024-08-08)
A Halley-type comet with an orbital period of about 133 years, Comet 109P/Swift-Tuttle is recognized as the parent of the annual Perseid Meteor Shower. The comet's last visit to the inner Solar System was in 1992. Then, it did not become easily visible to the naked eye, but it did become bright enough to see from most locations with binoculars and small telescopes. This stunning color image of Swift-Tuttle's greenish coma, long ion tail and dust tail was recorded using film on November 24, 1992. That was about 16 days after the large periodic comet's closest approach to Earth. Comet Swift-Tuttle is expected to next make an impressive appearance in night skies in 2126. Meanwhile, dusty cometary debris left along the orbit of Swift-Tuttle will continue to be swept up creating planet Earth's best-known July and August meteor shower.
A Perseid Below (2024-08-09)
Denizens of planet Earth typically watch meteor showers by looking up. But this remarkable view, captured on August 13, 2011 by astronaut Ron Garan, caught a Perseid meteor by looking down. From Garan's perspective on board the International Space Station orbiting at an altitude of about 380 kilometers, the Perseid meteors streak below, swept up dust from comet Swift-Tuttle. The vaporizing comet dust grains are traveling at about 60 kilometers per second through the denser atmosphere around 100 kilometers above Earth's surface. In this case, the foreshortened meteor flash is near frame center, below the curving limb of the Earth and a layer of greenish airglow, just below bright star Arcturus. Want to look up at a meteor shower?  You're in luck, as the 2024 Perseid meteor shower is active now and predicted to peak near August 12. With interfering bright moonlight absent, this year you'll likely see many Perseid meteors under clear, dark skies after midnight.
The Light, Dark, and Dusty Trifid (2024-08-10)
Messier 20, popularly known as the Trifid Nebula, lies about 5,000 light-years away toward the nebula rich constellation Sagittarius. A star forming region in the plane of our galaxy, the Trifid does illustrate three different types of astronomical nebulae; red emission nebulae dominated by light from hydrogen atoms, blue reflection nebulae produced by dust reflecting starlight, and dark nebulae where dense dust clouds appear in silhouette. The reddish emission region, roughly separated into three parts by obscuring dust lanes, is what lends the Trifid its popular name. The cosmic cloud complex is over 40 light-years across and would cover the area of a full moon on planet Earth's sky. But the Trifid Nebula is too faint to be seen by the unaided eye. Over 75 hours of image data captured under dark night skies was used to create this stunning telescopic view.  Watch: The Perseid Meteor Shower
Perseid Meteors over Stonehenge (2024-08-12)
What's happening in the sky above Stonehenge? A meteor shower: specifically, the Perseid meteor shower. A few nights ago, after the sky darkened, many images of meteors from this year's Perseids were captured separately and merged into a single frame. Although the meteors all traveled on straight paths, these paths appear slightly curved by the wide-angle lens of the capturing camera. The meteor streaks can all be traced back to a single point on the sky called the radiant, here just off the top of the frame in the constellation of Perseus. The same camera took a deep image of the background sky that brought up the central band of our Milky Way galaxy running nearly vertical through the image center. The featured image was taken from Wiltshire, England, being careful to include, at the bottom, the famous astronomical monument of Stonehenge. Although the Perseids peaked last night, some Perseid meteors should still be visible for a few more nights.
Giant Jet from the International Space Station (2024-08-13)
What's that on the horizon? When circling the Earth on the International Space Station early last month, astronaut Matthew Dominick saw an unusual type of lightning just beyond the Earth's edge: a gigantic jet. The powerful jet appears on the left of the featured image in red and blue. Giant jet lightning has only been known about for the past 23 years. The atmospheric jets are associated with thunderstorms and extend upwards towards Earth's ionosphere.  The lower part of the frame shows the Earth at night, with Earth's thin atmosphere tinted green from airglow. City lights are visible, sometimes resolved, but usually creating diffuse white glows in intervening clouds.  The top of the frame reveals distant stars in the dark night sky. The nature of gigantic jets and their possible association with other types of Transient Luminous Events (TLEs) such as blue jets and red sprites remains an active topic of research.   Growing Gallery: Perseid Meteor Shower 2024 and Aurorae
Meteors and Aurora over Germany (2024-08-14)
This was an unusual night. For one thing, the night sky of August 11 and 12, earlier this week, occurred near the peak of the annual Perseid Meteor Shower. Therefore, meteors streaked across the dark night as small bits cast off from Comet Swift-Tuttle came crashing into the Earth's atmosphere. Even more unusually, for central Germany at least, the night sky glowed purple. The red-blue hue was due to aurora caused by an explosion of particles from the Sun a few days before. This auroral storm was so intense that it was seen as far south as Texas and Italy, in Earth's northern hemisphere.  The featured image composite was built from 7 exposures taken over 26 minutes from Ense, Germany. The Perseids occur predictably every August, but auroras visible this far south are more unusual and less predictable.   Gallery: Perseid Meteor Shower 2024 and Aurorae
Late Night Vallentuna (2024-08-15)
Bright Mars and even brighter Jupiter are in close conjunction just above the pine trees in this post-midnight skyscape from Vallentuna, Sweden. Taken on August 12 during a geomagnetic storm, the snapshot records the glow of aurora borealis or northern lights, beaming from the left side of the frame. Of course on that date Perseid meteors rained through planet Earth's skies, grains of dust from the shower's parent, periodic comet Swift-Tuttle. The meteor streak at the upper right is a Perseid plowing through the atmosphere at about 60 kilometers per second. Also well-known in Earth's night sky, the bright Pleiades star cluster shines below the Perseid meteor streak. In Greek myth, the Pleiades were seven daughters of the astronomical titan Atlas and sea-nymph Pleione. The Pleiades and their parents' names are given to the cluster's nine brightest stars.   Gallery: Perseid Meteor Shower 2024 and Aurorae
Meteor Borealis (2024-08-16)
A single exposure made with a camera pointed almost due north on August 12 recorded this bright Perseid meteor in the night sky west of Halifax, Nova Scotia, Canada. The meteor's incandescent trace is fleeting. It appears to cross the stars of the Big Dipper, famous northern asterism and celestial kitchen utensil, while shimmering curtains of aurora borealis, also known as the northern lights, dance in the night. Doubling the wow factor for night skywatchers near the peak of this year's Perseid meteor shower auroral activity on planet Earth was enhanced by geomagnetic storms. The intense space weather was triggered by flares from an active Sun.   Gallery: Perseid Meteor Shower 2024 and Aurorae
Sky Full of Arcs (2024-08-17)
On August 11 a Rocket Lab Electron rocket launched from a rotating planet. With a small satellite on board its mission was dubbed A Sky Full of SARs (Synthetic Aperture Radar satellites), departing for low Earth orbit from Mahia Peninsula on New Zealand's north island. The fiery trace of the Electron's graceful launch arc is toward the east in this southern sea and skyscape, a composite of 50 consecutive frames taken over 2.5 hours. Fixed to a tripod, the camera was pointing directly at the South Celestial Pole, the extension of planet Earth's axis of rotation in to space. But no bright star marks that location in the southern hemisphere's night sky. Still, the South Celestial Pole is easy to spot. It lies at the center of the concentric star trail arcs that fill the skyward field of view.   Gallery: Perseid Meteor Shower 2024 and Aurorae
IC 5146: The Cocoon Nebula (2024-08-19)
Inside the Cocoon Nebula is a newly developing cluster of stars. Cataloged as IC 5146, the beautiful nebula is nearly 15 light-years wide. Soaring high in northern summer night skies, it's located some 4,000 light years away toward the constellation of the Swan (Cygnus).  Like other star forming regions, it stands out in red, glowing, hydrogen gas excited by young, hot stars, and dust-reflected starlight at the edge of an otherwise invisible molecular cloud.  In fact, the bright star found near the center of this nebula is likely only a few hundred thousand years old, powering the nebular glow as it clears out a cavity in the molecular cloud's star forming dust and gas. A 48-hour long integration resulted in this exceptionally deep color view tracing tantalizing features within and surrounding the dusty stellar nursery.
Supermoon Beyond the Temple of Poseidon (2024-08-20)
A supermoon occurred yesterday. And tonight's moon should also look impressive.  Supermoons appear slightly larger and brighter than most full moons because they reach their full phase when slightly nearer to the Earth -- closer than 90 percent of all full moons.  This supermoon was also a blue moon given the definition that it is the third of four full moons occurring during a single season.  Blue moons are not usually blue, and a different definition holds that a blue moon is the second full moon that occurs during a single month.  The featured image captured the blue supermoon right near its peak size yesterday as it was rising beyond the Temple of Poseidon in Greece. This supermoon is particularly unusual in that it is the first of four successive supermoons, the next three occurring in September, October, and November.