juliensimon/nasa-apod huggingface dataset:
Central Lagoon in Infrared (2021-03-19)

Stars fill this infrared view, spanning 4 light-years across the center of the Lagoon Nebula. Visible light images show the glowing gas and obscuring dust clouds that dominate the scene. But this infrared image, constructed from Hubble Space Telescope data, peers closer to the heart of the active star-forming region revealing newborn stars scattered within, against a crowded field of background stars toward the center of our Milky Way galaxy. This tumultuous stellar nursery's central regions are sculpted and energized by the massive, young Herschel 36, seen as the bright star near center in the field of view. Herschel 36 is actually a multiple system of massive stars. At over 30 times the mass of the Sun and less than 1 million years old, the most massive star in the system should live to a stellar old age of 5 million years. Compare that to the almost 5 billion year old Sun which will evolve into a red giant in only another 5 billion years or so. The Lagoon Nebula, also known as M8, lies about 4,000 light-years away within the boundaries of the constellation Sagittarius.
The Leo Trio (2021-03-20)

This popular group leaps into the early evening sky around the March equinox and the northern hemisphere spring. Famous as the Leo Triplet, the three magnificent galaxies found in the prominent constellation Leo gather here in one astronomical field of view. Crowd pleasers when imaged with even modest telescopes, they can be introduced individually as NGC 3628 (right), M66 (upper left), and M65 (bottom). All three are large spiral galaxies but tend to look dissimilar, because their galactic disks are tilted at different angles to our line of sight. NGC 3628, also known as the Hamburger Galaxy, is temptingly seen edge-on, with obscuring dust lanes cutting across its puffy galactic plane. The disks of M66 and M65 are both inclined enough to show off their spiral structure.  Gravitational interactions between galaxies in the group have left telltale signs, including the tidal tails and warped, inflated disk of NGC 3628 and the drawn out spiral arms of M66. This gorgeous view of the region spans over 1 degree (two full moons) on the sky in a frame that covers over half a million light-years at the trio's estimated distance of 30 million light-years. Of course the spiky foreground stars lie well within our own Milky Way.

Image credit: Francis Bozon
The Antikythera Mechanism (2021-03-21)

No one knew that 2,000 years ago, the technology existed to build such a device.  The Antikythera mechanism, pictured, is now widely regarded as the first computer. Found at the bottom of the sea aboard a decaying Greek ship, its complexity prompted decades of study, and even today some of its functions likely remain unknown.  X-ray images of the device, however, have confirmed that a main function of its numerous clock-like wheels and gears is to create a portable, hand-cranked, Earth-centered, orrery of the sky, predicting future star and planet locations as well as lunar and solar eclipses.  The corroded core of the Antikythera mechanism's largest gear is featured, spanning about 13 centimeters, while the entire mechanism was 33 centimeters high, making it similar in size to a large book. Recently, modern computer modeling of missing components is allowing for the creation of a more complete replica of this surprising ancient machine.
From Auriga to Orion (2021-03-22)

What's up in the sky from Auriga to Orion? Many of the famous stars and nebulas in this region were captured on 34 separate images, taking over 430 hours of exposure, and digitally combined to reveal the featured image. Starting on the far upper left, toward the constellation of Auriga (the Chariot driver), is the picturesque Flaming Star Nebula (IC 405).  Continuing down along the bright arc of our Milky Way Galaxy, from left to right crossing the constellations of the Twins and the Bull, notable appearing nebulas include the Tadpole, Simeis 147, Monkey Head, Jellyfish, Cone and Rosette nebulas.  In the upper right quadrant of the image, toward the constellation of Orion (the hunter), you can see Sh2-264, the half-circle of Barnard's Loop, and the Horsehead and Orion nebulas. Famous stars in and around Orion include, from left to right, orange Betelgeuse (just right of the image center), blue Bellatrix (just above it), the Orion belt stars of Mintaka, Alnilam, and Alnitak, while bright Rigel appears on the far upper right. This stretch of sky won't be remaining up in the night very long -- it will be setting continually earlier in the evening as mid-year approaches.

Image credit: Alistair Symon
Mars over Duddo Stone Circle (2021-03-23)

Why are these large stones here? One the more famous stone circles is the Duddo Five Stones of Northumberland, England.  Set in the open near the top of a modest incline, a short hike across empty fields will bring you to unusual human -sized stones that are unlike anything surrounding them. The grooved, pitted, and deeply weathered surfaces of the soft sandstones are consistent with being placed about 4000 years ago -- but placed for reasons now unknown.  The featured image -- a composite of two consecutive images taken from the same location -- was captured last October under a starry sky when the Earth was passing near Mars, making the red planet unusually large and bright.  Mars remains visible at sunset, although increasingly close to the horizon over the next few months.   APOD via Instagram in: English, Indonesian, Persian, and Portuguese

Image credit: Ged Kivlehan
Aurorae and Lightning on Jupiter (2021-03-24)

Why does so much of Jupiter's lightning occur near its poles? Similar to Earth, Jupiter experiences both aurorae and lightning. Different from Earth, though, Jupiter's lightning usually occurs near its poles -- while much of Earth's lightning occurs near its equator. To help understand the difference, NASA's Juno spacecraft, currently orbiting Jupiter, has observed numerous aurora and lightning events. The featured image, taken by Juno's Stellar Reference Unit camera on 2018 May 24, shows Jupiter's northern auroral oval and several bright dots and streaks. An eye-catching event is shown in the right inset image -- which is a flash of Jupiter's lightning -- one of the closest images of aurora and lightning ever. On Earth (which is much nearer to the Sun than Jupiter), sunlight is bright enough to create, by itself, much stronger atmospheric heating at the equator than the poles, driving turbulence, storms, and lightning. On Jupiter, in contrast, atmospheric heating comes mostly from its interior (as a remnant from its formation), leading to the hypothesis that more intense equatorial sunlight  reduces temperature differences between upper atmospheric levels, hence reducing equatorial lightning-creating storms.   APOD via Facebook in: in English, Catalan and Portuguese
Curiosity: Sol 3048 (2021-03-25)

Before Perseverance there was Curiosity. In fact, the Curiosity rover accomplished the first sky crane maneuver touchdown on Mars on August 5, 2012. March 2, 2021 marked Curiosity's 3,048th martian day operating on the surface of the Red Planet. This 360 degree panorama from sol 3048 is a mosaic of 149 frames from Curiosity's Mastcam above the rover's deck. It includes 23 frames of icy, thin, high clouds drifting through the martian sky. The cloudy sky frames were recorded throughout that martian day and are digitally stitched together in the panoramic view. Near center is a layered and streaked Mont Mercou. The peak of central Mount Sharp, rising over 5 kilometers above the floor of Gale Crater, is in the distant background on the left.
The Medusa Nebula (2021-03-26)

Braided and serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star is the faint one near the center of the overall bright crescent shape. In this deep telescopic view, fainter filaments clearly extend above and right of the bright crescent region. The Medusa Nebula is estimated to be over 4 light-years across.

Image credit: Josep Drudis
Exploring the Antennae (2021-03-27)

Some 60 million light-years away in the southerly constellation Corvus, two large galaxies are colliding. Stars in the two galaxies, cataloged as NGC 4038 and NGC 4039, very rarely collide in the course of the ponderous cataclysm that lasts for hundreds of millions of years. But the galaxies' large clouds of molecular gas and dust often do, triggering furious episodes of star formationi near the center of the cosmic wreckage. Spanning over 500 thousand light-years, this stunning view also reveals new star clusters and matter flung far from the scene of the accident by gravitational tidal forces. The remarkably sharp ground-based image includes narrowband data that highlights the characteristic red glow of atomic hydrogen gas in star-forming regions. The suggestive overall visual appearance of the extended arcing structures gives the galaxy pair its popular name - The Antennae.

Image credit: Bernard Miller
SuitSat-1: A Spacesuit Floats Free (2021-03-28)

A spacesuit floated away from the International Space Station 15 years ago, but no investigation was conducted.  Everyone knew that it was pushed by the space station crew.   Dubbed Suitsat-1, the unneeded Russian Orlan spacesuit filled mostly with old clothes was fitted with a faint radio transmitter and released to orbit the Earth. The suit circled the Earth twice before its radio signal became unexpectedly weak. Suitsat-1 continued to orbit every 90 minutes until it burned up in the Earth's atmosphere after a few weeks.  Pictured, the lifeless spacesuit was photographed in 2006 just as it drifted away from  space station.    Portal Universe: Random APOD Generator
M64: The Evil Eye Galaxy (2021-03-29)

Who knows what evil lurks in the eyes of galaxies? The Hubble knows -- or in the case of spiral galaxy M64 -- is helping to find out. Messier 64, also known as the Evil Eye or Sleeping Beauty Galaxy, may seem to have evil in its eye because all of its stars rotate in the same direction as the interstellar gas in the galaxy's central region, but in the opposite direction in the outer regions. Captured here in great detail by the Earth-orbiting Hubble Space Telescope, enormous dust clouds obscure the near-side of M64's central region, which are laced with the telltale reddish glow of hydrogen associated with star formation.  M64 lies about 17 million light years away, meaning that the light we see from it today left when the last common ancestor between humans and chimpanzees roamed the Earth.  The dusty eye and bizarre rotation are likely the result of a billion-year-old merger of two different galaxies.
Red Sprite Lightning over the Andes (2021-03-30)

What are those red filaments in the sky? They are a rarely seen form of lightning confirmed only about 30 years ago: red sprites. Recent research has shown that following a powerful positive cloud-to-ground lightning strike, red sprites may start as 100-meter balls of ionized air that shoot down from about 80-km high at 10 percent the speed of light. They are quickly followed by a group of upward streaking ionized balls. The featured image was taken earlier this year from Las Campanas observatory in Chile over the Andes Mountains in Argentina. Red sprites take only a fraction of a second to occur and are best seen when powerful thunderstorms are visible from the side.    APOD via Instagram in: English, Indonesian, Persian, and Portuguese

Image credit: Yuri Beletsky
(Carnegie
Las Campanas Observatory,
TWAN)
M87's Central Black Hole in Polarized Light (2021-03-31)

To play on Carl Sagan’s famous words "If you wish to make black hole jets, you must first create magnetic fields." The featured image represents the detected intrinsic spin direction (polarization) of radio waves.  The polarizationi is produced by the powerful magnetic field surrounding the supermassive black hole at the center of elliptical galaxy M87. The radio waves were detected by the Event Horizon Telescope (EHT), which combines data from radio telescopes distributed worldwide.  The polarization structure, mapped using computer generated flow lines, is overlaid on EHT’s famous black hole image, first published in 2019. The full 3-D magnetic field is complex.  Preliminary analyses indicate that parts of the field circle around the black hole along with the accreting matter, as expected.  However, another component seemingly veers vertically away from the black hole.  This component could explain how matter resists falling in and is instead launched into M87’s jet.
Rocket Launch as Seen from the Space Station (2021-04-01)

Have you ever seen a rocket launch -- from space?  A close inspection of the featured time-lapse video will reveal a rocket rising to Earth orbit as seen from the International Space Station (ISS).  The Russian Soyuz-FG rocket was launched in November 2018 from the Baikonur Cosmodrome in Kazakhstan, carrying a Progress MS-10 (also 71P) module to bring needed supplies to the ISS.  Highlights in the 90-second video (condensing about 15-minutes) include city lights and clouds visible on the Earth on the lower left, blue and gold bands of atmospheric airglow running diagonally across the center, and distant stars on the upper right that set behind the Earth. A lower stage can be seen falling back to Earth as the robotic supply ship fires its thrusters and begins to close on the ISS, a space laboratory that celebrated its 20th anniversary in 2018. Astronauts who live aboard the Earth-orbiting ISS conduct, among more practical duties, numerous science experiments that expand human knowledge and enable future commercial industry in low Earth orbit.
NGC 3521: Galaxy in a Bubble (2021-04-02)

Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like M66 and M65. It's hard to overlook in this colorful cosmic portrait, though. Spanning some 50,000 light-years the galaxy sports characteristic patchy, irregular spiral arms laced with dust, pink star forming regions, and clusters of young, blue stars. Remarkably, this deep image also finds NGC 3521 embedded in gigantic bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have undergone mergers with NGC 3521 in the distant past.

Image credit: Eric Benson
Ingenuity on Sol 39 (2021-04-03)

The Mars Ingenuity Helicopter, all four landing legs down, was captured here on sol 39 (March 30) slung beneath the belly of the Perseverance rover. The near ground level view is a mosaic of images from the WATSON camera on the rover's SHERLOC robotic arm. Near the center of the frame the experimental helicopter is suspended just a few centimeters above the martian surface. Tracks from Perseverance extend beyond the rover's wheels with the rim of Jezero crater visible about 2 kilometers in the distance. Ingenuity has a weight of 1.8 kilograms or 4 pounds on Earth. That corresponds to a weight of 0.68 kilograms or 1.5 pounds on Mars. With rotor blades spanning 1.2 meters it will attempt to make the first powered flight of an aircraft on another planet in the thin martian atmosphere, 1 percent as dense as Earth's, no earlier than April 11.
In, Through, and Beyond Saturn's Rings (2021-04-04)

Four moons are visible on the featured image -- can you find them all? First -- and farthest in the background -- is Titan, the largest moon of Saturn and one of the larger moons in the Solar System.  The dark feature across the top of this perpetually cloudy world is the north polar hood. The next most obvious moon is bright Dione, visible in the foreground, complete with craters and long ice cliffs. Jutting in from the left are several of Saturn's expansive rings, including Saturn's A ring featuring the dark Encke Gap. On the far right, just outside the rings, is Pandora, a moon only 80-kilometers across that helps shepherd Saturn's F ring. The fourth moon?  If you look closely inside Saturn's rings, in the Encke Gap, you will find a speck that is actually Pan. Although one of Saturn's smallest moons at 35-kilometers across, Pan is massive enough to help keep the Encke gap relatively free of ring particles. After more than a decade of exploration and discovery, the Cassini spacecraft ran low on fuel in 2017 and was directed to enter Saturn's atmosphere, where it surely melted.
Veil Nebula: Wisps of an Exploded Star (2021-04-05)

Wisps like this are all that remain visible of a Milky Way star.  About 7,000 years ago that star exploded in a supernova leaving the Veil Nebula. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history.  Today, the resulting supernova remnant, also known as the Cygnus Loop, has faded and is now visible only through a small telescope directed toward the constellation of the Swan (Cygnus). The remaining Veil Nebula is physically huge, however, and even though it lies about 1,400 light-years distant, it covers over five times the size of the full Moon.  The featured picture is a Hubble Space Telescope mosaic of six images together covering a span of only about two light years, a small part of the expansive supernova remnant. In images of the complete Veil Nebula, even studious readers might not be able to identify the featured filaments.
Mars and the Pleiades Beyond Vinegar Hill (2021-04-06)

Is this just a lonely tree on an empty hill? To start, perhaps, but look beyond.  There, a busy universe may wait to be discovered. First, physically, to the left of the tree, is the planet Mars. The red planet, which is the new home to NASA's Perseverance rover, remains visible this month at sunset above the western horizon. To the tree's right is the Pleiades, a bright cluster of stars dominated by several bright blue stars. The featured picture is a composite of several separate foreground and background images taken within a few hours of each other, early last month, from the same location on Vinegar Hill in Milford, Nova Scotia, Canada. At that time, Mars was passing slowly, night after night, nearly in front of the distant Seven Sisters star cluster. The next time Mars will pass angularly as close to the Pleiades as it did in March will be in 2038.

Image credit: Kristine Richer
Threads of NGC 1947 (2021-04-07)

Found in far southern skies, deep within the boundaries of the constellation Dorado, NGC 1947 is some 40 million light-years away. In silhouette against starlight, obscuring lanes of cosmic dust thread across the peculiar galaxy's bright central regions. Unlike the rotation of stars, gas, and dust tracing the arms of spiral galaxies, the motions of dust and gas don't follow the motions of stars in NGC 1947 though. Their more complicated disconnected motion suggest this galaxy's visible threads of dust and gas may have come from a donor galaxy, accreted by NGC 1947 during the last 3 billion years or so of the peculiar galaxy's evolution. With spiky foreground Milky Way stars and even more distant background galaxies scattered through the frame, this sharp Hubble image spans about 25,000 light-years near the center of NGC 1947.
3D Ingenuity (2021-04-08)

The multicolor, stereo imaging Mastcam-Z on the Perseverance rover zoomed in to captured this 3D close-up (get out your red/blue glasses) of the Mars Ingenuity helicopter on mission sol 45, April 5. That's only a few sols before the technology demonstrating Ingenuity will attempt to fly in the thin martian atmosphere, making the first powered flight on another planet. The historic test flight is planned for no earlier than Sunday, April 11.  Casting its shadow on the martian surface, Ingenuity is standing alone on four landing legs next to the rover's wheel tracks. The experimental helicopter's solar panel, charging batteries that keep it warm through the cold martian nights and power its flight, sits above its two 1.2 meter (4 foot) long counter-rotating blades.
Messier 106 (2021-04-09)

Close to the Great Bear (Ursa Major) and surrounded by the stars of the Hunting Dogs (Canes Venatici), this celestial wonder was discovered in 1781 by the metric French astronomer Pierre Mechain. Later, it was added to the catalog of his friend and colleague Charles Messier as M106. Modern deep telescopic views reveal it to be an island universe - a spiral galaxy around 30 thousand light-years across located only about 21 million light-years beyond the stars of the Milky Way. Along with a bright central core, this stunning galaxy portrait, a composite of image data from amateur and professional telescopes, highlights youthful blue star clusters and reddish stellar nurseries tracing the galaxy's spiral arms. It also shows off remarkable reddish jets of glowing hydrogen gas. In addition to small companion galaxy NGC 4248 at bottom right, background galaxies can be found scattered throughout the frame. M106, also known as NGC 4258, is a nearby example of the Seyfert class of active galaxies, seen across the spectrum from radio to X-rays. Active galaxies are powered by matter falling into a massive central black hole.

Image credit: Robert Gendler
Zodiacal Night (2021-04-10)

An intense band of zodiacal light is captured in this serene mountain and night skyscape from April 7. The panoramic view was recorded after three hours of hiking from a vantage looking west after sunset across the Pyrenees in southern France. At 2838 meters altitude, Mont Valier is the tallest peak near center. In the sky above, the familiar stars of Orion and the northern winter Milky Way are approaching the rugged western horizon. At the shoulder of Orion, Betelgeuse is one of three bright yellowish celestial beacons. It forms a triangle with fellow red giant star Aldebaran located below Betelgeuse and to the right, and the red planet Mars. Mars shines just under the band of the Milky Way, still immersed in the bright zodiacal light.   Tournament Earth: Vote for your favorite image from NASA's Earth Observatory

Image credit: Jean-Francois
Graffand
When Black Holes Collide (2021-04-11)

What happens when two black holes collide? This extreme scenario occurs in the centers of many merging galaxies and multiple star systems. The featured video shows a computer animation of the final stages of such a merger, while highlighting the gravitational lensing effects that would appear on a background starfield. The black regions indicate the event horizons of the dynamic duo, while a surrounding ring of shifting background stars indicates the position of their combined Einstein ring. All background stars not only have images visible outside of this Einstein ring, but also have one or more companion images visible on the inside. Eventually the two black holes coalesce.  The end stages of such a merger is now known to produce a strong blast of gravitational radiation, providing a new way to see our universe.    This Week is: Black Hole Week at NASA

Image credit: Simulating Extreme Spacetimes
Collaboration