juliensimon/nasa-apod huggingface dataset:
Grand Spiral NGC 5643 (2024-12-26)

Viewed face-on, grand spiral galaxy NGC 5643 has a festive appearance in this colorful cosmic portrait. Some 55 million light-years distant, the galaxy extends for over 100,000 light-years, seen within the boundaries of the southern constellation Lupus. Its inner 40,000 light-years are shown in sharp detail in this composite of Hubble Space Telescope image data. The galaxy's magnificent spiral arms wind from a yellowish central region dominated by light from old stars, while the spiral arms themselves are traced by dust lanes, young blue stars and reddish star forming regions. The bright compact core of NGC 5643 is also known as a strong emitter of radio waves and X-rays. In fact, NGC 5643 is one of the closest examples of the Seyfert class of active galaxies, where vast amounts of dust and gas are thought to be falling into a central massive black hole.
Planet Earth at Twilight (2024-12-27)

No sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual transition to darkness we experience as twilight. With the Sun illuminating the scene from the right, the cloud tops reflect gently reddened sunlight filtered through the dusty troposphere, the lowest layer of the planet's nurturing atmosphere. A clear high altitude layer, visible along the dayside's upper edge, scatters blue sunlight and fades into the blackness of space. This picture was taken from the International Space Station orbiting at an altitude of 211 nautical miles. Of course from home, you can check out the Earth Now.
A December Winter Night (2024-12-28)

Orion seems to come up sideways, climbing over a distant mountain range in this deep skyscape. The wintry scene was captured from southern Poland on the northern hemisphere's long solstice night. Otherwise unseen nebulae hang in the sky, revealed by the camera modified to record red hydrogen-alpha light. The nebulae lie near the edge of the Orion molecular cloud and join the Hunter's familiar belt stars and bright giants Betelgeuse and Rigel. Eye of Taurus the Bull, yellowish Aldebaran anchors the V-shaped Hyades star cluster near top center. Still, near opposition in planet Earth's sky, the Solar System's ruling gas giant Jupiter is the brightest celestial beacon above this horizon's snowy peaks.

Image credit: Włodzimierz Bubak
Methane Bubbles Frozen in Lake Baikal (2024-12-29)

What are these bubbles frozen into Lake Baikal? Methane.  Lake Baikal, a UNESCO World Heritage Site in Russia, is the world's largest (by volume), oldest, and deepest lake, containing over 20% of the world's fresh water. The lake is also a vast storehouse of methane, a greenhouse gas that, if released, could potentially increase the amount of infrared light absorbed by Earth's atmosphere, and so increase the average temperature of the entire planet. Fortunately, the amount of methane currently bubbling out is not climatologically important. It is not clear what would happen, though, were temperatures to significantly increase in the region, or if the water level in Lake Baikal were to drop.  Pictured, bubbles of rising methane froze during winter into the exceptionally clear ice covering the lake.   Jigsaw Challenge: Astronomy Puzzle of the Day

Image credit: Kristina Makeeva
M27: The Dumbbell Nebula (2024-12-30)

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 nebulas 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 shapes are created.    APOD Year in Review: Night Sky Network Presentation for 2024

Image credit: Christopher Stobie
The Twisted Disk of NGC 4753 (2024-12-31)

What do you think this is?  Here’s a clue: it's bigger than a bread box. Much bigger. The answer is that pictured NGC 4753 is a twisted disk galaxy, where unusual dark dust filaments provide clues about its history. No one is sure what happened, but a leading model holds that a relatively normal disk galaxy gravitationally ripped apart a dusty satellite galaxy while its precession distorted the plane of the accreted debris as it rotated.  The cosmic collision is hypothesized to have started about a billion years ago.  NGC 4753 is seen from the side, and possibly would look like a normal spiral galaxy from the top.  The bright orange halo is composed of many older stars that might trace dark matter. The featured Hubble image was recently reprocessed to highlight ultraviolet and red-light emissions.    APOD Year in Review: NASA Night Sky Network Presentation for 2024
Alpha Centauri: The Closest Star System (2025-01-01)

The closest star system to the Sun is the Alpha Centauri system. Of the three stars in the system, the dimmest -- called Proxima Centauri -- is actually the nearest star. The bright stars Alpha Centauri A and B form a close binary as they are separated by only 23 times the Earth- Sun distance - slightly greater than the distance between Uranus and the Sun. The Alphasystem is not visible in much of the northern hemisphere. Alpha Centauri A, also known as Rigil Kentaurus, is the brightest star in the constellation of Centaurus and is the fourth brightest star in the night sky. Sirius is the brightest even though it is more than twice as far away. By an exciting coincidence, Alpha Centauri A is the same type of star as our Sun, and Proxima Centauri is now known to have a potentially habitable exoplanet.

Image credit: Telescope Live, Heaven's Mirror Observatory; 
Processing: Chris Cantrell
Solar Analemma 2024 (2025-01-02)

Recorded during 2024, this year-spanning series of images reveals a pattern in the seasonal drift of the Sun's daily motion through planet Earth's sky. Known to some as an analemma, the figure-eight curve was captured in exposures taken only at 1pm local time on clear days from Kayseri, Turkiye. Of course the Sun's position on the 2024 solstice dates was at the top and bottom of the curve. They correspond to the astronomical beginning of summer and winter in the north. The points along the curve half-way between the solstices, but not the figure-eight curve crossing point, mark the 2024 equinoxes and the start of spring and fall. Regional peaks and dormant volcano Mount Erciyes lie along the southern horizon in the 2024 timelapse skyscape.

Image credit: Betul Turksoy
Eclipse Pair (2025-01-03)

clipses tend to come in pairs. Twice a year, during an eclipse season that lasts about 34 days, Sun, Moon, and Earth can nearly align. Then the full and new phases of the Moon, separated by just over 14 days, create a lunar and a solar eclipse. But only rarely is the alignment at both new moon and full moon phases during a single eclipse season close enough to produce a pair with both total (or a total and an annular) lunar and solar eclipses. More often, partial eclipses are part of any eclipse season. In fact, the last eclipse season of 2024 produced this fortnight-separated eclipse pair: a partial lunar eclipse on 18 September and an annular solar eclipse on 2 October. The time-lapse composite images were captured from Somerset, UK (left) and Rapa Nui planet Earth. The 2025 eclipse seasons will see a total lunar eclipse on 14 March paired with a partial solar eclipse on 29 March, and a total lunar eclipse on 8 September followed by a partial solar eclipse on 21 September.

Image credit: Josh Dury
Welcome to Perihelion (2025-01-04)

rth's orbit around the Sun is not a circle, it's an ellipse. The point along its elliptical orbit where our fair planet is closest to the Sun is called perihelion. This year perihelion is today, January 4, at 13:28 UTC, only a few hours before this H-alpha picture of the active Sun was taken. At perihelion the Earth was about 147 million kilometers from the Sun. For comparison, at aphelion on last July 3 Earth was at its farthest distance from the Sun, some 152 million kilometers away. But distance from the Sun doesn't determine Earth's seasons. It's only by coincidence that the beginning of southern summer (northern winter) on the December solstice is within 14 days of Earth's perihelion date. And it's only by coincidence that Earth's perihelion date is within 11 days of the historic perihelion of NASA's Parker Solar Probe. Launched in 2018, the Parker Solar Probe flew within 6.2 million kilometers of the Sun's surface on 2024 December 24, breaking its own record for closest perihelion for a spacecraft from planet Earth.

Image credit: Barden Ridge Observatory
Rocket Launch as Seen from the International Space Station (2025-01-05)

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 25th anniversary in 2023. 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.
Colliding Spiral Galaxies from Webb and Hubble (2025-01-06)

Billions of years from now, only one of these two galaxies will remain.  Until then, spiral galaxies NGC 2207 and IC 2163 will slowly pull each other apart, creating tides of matter, sheets of shocked gas, lanes of dark dust, bursts of star formation, and streams of cast-away stars.  The featured image in scientifically assigned colors is a composite of Hubble exposures in visible light and Webb exposures in infrared light. Astronomers predict that NGC 2207, the larger galaxy on the right, will eventually incorporate IC 2163, the smaller galaxy on the left.  In the most recent encounter that about peaked 40 million years ago, the smaller galaxy is swinging around counter-clockwise and is now slightly behind the larger galaxy.  The space between stars is so vast that when galaxies collide, the stars in them usually do not collide.   Jigsaw Challenge: Astronomy Puzzle of the Day
A New Year's Aurora and SAR Arc (2025-01-07)

It was a new year, and the sky was doubly red.  The new year meant that the Earth had returned to its usual place in its orbit on January 1, a place a few days before its closest approach to the Sun.  The first of the two red skyglows, on the left, was a red aurora, complete with vertical rays, caused by a blast from the Sun pushing charged particles into Earth's atmosphere.  The second red glow, most prominent on the far right, was possibly a SAR arc caused by a river of charged particles flowing across Earth's atmosphere.  Although both appear red, the slight color difference is likely due to the aurora being emitted by both oxygen and nitrogen, whereas the higher SAR arc was possibly emitted more purely by atmospheric oxygen. The featured image was taken on January 1 from near Pieve di Cadore in Italy.   Portal Universe: Random APOD Generator

Image credit: Alessandra Masi
Supernova Remnants Big and Small (2025-01-08)

What happens after a star explodes?  A huge fireball of hot gas shoots out in all directions.  When this gas slams into the existing interstellar medium, it heats up so much it glows. Two different supernova remnants (SNRs) are visible in the featured image, taken at the Oukaïmeden Observatory in Morocco.  The blue soccer ball-looking nebula toward the upper left is SNR G179.0+02.6, which appears to be the smaller one.  This supernova, about 11,000 light years distant, detonated about 50,000 years ago. Although composed mostly of hydrogen gas, the blue light is emitted by a trace amount of oxygen.  The seemingly larger SNR, dominating the lower right of the frame, is the Spaghetti Nebula, cataloged as Simeis 147 and sh2-240.  This supernova, only about 3,000 light years away, exploded about 40,000 years ago. Comparatively, even though they appear different sizes, both supernova remnants are not only roughly the same age, but about the same size, too.

Image credit: Stéphane Vetter
(Nuits sacrées)
Peculiar Galaxies of Arp 273 (2025-01-09)

The colorful, spiky stars are in the foreground of this image taken with a small telescope on planet Earth. They lie well within our own Milky Way Galaxy. But the two eye-catching galaxies in the frame lie far beyond the Milky Way, at a distance of over 300 million light-years. The galaxies' twisted and distorted appearance is due to mutual gravitational tides as the pair engage in close encounters. Cataloged as Arp 273 (also as UGC 1810), these galaxies do look peculiar, but interacting galaxies are now understood to be common in the universe. Closer to home, the large spiral Andromeda Galaxy is known to be some 2 million light-years away and inexorably approaching the Milky Way.  In fact the far away peculiar galaxies of Arp 273 may offer an analog of the far future encounter of Andromeda and Milky Way. Repeated galaxy encounters on a cosmic timescale ultimately result in a merger into a single galaxy of stars. From our perspective, the bright cores of the Arp 273 galaxies are separated by only a little over 100,000 light-years.

Image credit: Dave Doctor
Young Stars, Dark Nebulae (2025-01-10)

An unassuming region in the constellation Taurus holds these dark and dusty nebulae. Scattered through the scene, stars in multiple star systems are forming within their natal Taurus molecular cloud complex some 450 light-years away. Millions of years young and still going through stellar adolescence, the stars are variable in brightness and in the late phases of their gravitational collapse. Known as T-Tauri class stars they tend to be faint and take on a yellowish hue in the image. One of the brightest T-Tauri stars in Taurus, V773 (aka HD283447) is near the center of the telescopic frame that spans over 1 degree. Toward the top is the dense, dark marking on the sky cataloged as Barnard 209.

Image credit: Long Xin
An Evening Sky Full of Planets (2025-01-11)

Only Mercury is missing from a Solar System parade of planets in this early evening skyscape. Rising nearly opposite the Sun, bright Mars is at the far left. The other naked-eye planets Jupiter, Saturn, and Venus, can also be spotted, with the positions of too-faint Uranus and Neptune marked near the arcing trace of the ecliptic plane. On the far right and close to the western horizon after sunset is a young crescent Moon whose surface is partly illuminated by earthshine.  In the foreground of the composite panorama captured on 2 January, planet Earth is represented by Mount Etna's lower Silvestri Crater. Of course Earth's early evening skies are full of planets for the entire month of January. On 13 January, a nearly Full Moon will appear to pass in front of Mars for skywatchers in the continental U.S. and Eastern Canada.

Image credit: Dario Giannobile
Mimas: Small Moon with a Big Crater (2025-01-12)

Whatever hit Mimas nearly destroyed it.  What remains is one of the largest impact craters on one of Saturn's smallest round moons.  Analysis indicates that a slightly larger impact would have destroyed Mimas entirely.  The huge crater, named Herschel after the 1789 discoverer of Mimas, Sir William Herschel, spans about 130 kilometers and is featured here. Mimas' low mass produces a surface gravity just strong enough to create a spherical body but weak enough to allow such relatively large surface features. Mimas is made of mostly water ice with a smattering of rock - so it is accurately described as a big dirty snowball. The featured image was taken during the closest-ever flyby of the robot spacecraft Cassini past Mimas in 2010 while in orbit around Saturn.    Interactive: Take a trek across Mimas  January 14: Zoom APOD Lecture hosted by the Amateur Astronomers of Association of New York
Comet ATLAS Before Sunrise (2025-01-13)

Comet ATLAS is really bright now, but also really close to the Sun. Outside the glow of the Sun, Comet C/2024 G3 (ATLAS) would be one of the more remarkable comet sights of recent years, reflecting about as much sunlight to Earth as Comet Tsuchinshan-ATLAS did in October, and now rivaling even planet Venus. But the giant snowball is now so close to the Sun that it can only be seen through the light of the early morning dawn or the early evening dusk. Today, Comet ATLAS is at perihelion -- its closest ever to the Sun.  Although the future brightness of comets is notoriously hard to predict, there is hope that Comet ATLAS will survive its close pass near the Sun and remain bright enough to be seen with the unaided eye over the next few days -- and possibly a good camera comet for weeks. The featured image was taken early yesterday morning near Tornaľa, Slovakia.   Tomorrow: Zoom APOD Lecture hosted by the Amateur Astronomers of Association of New York

Image credit: Petr Horalek /
Institute of Physics in Opava
North Star: Polaris and Surrounding Dust (2025-01-14)

Why is Polaris called the North Star? First, Polaris is the nearest bright star toward the north spin axis of the Earth.  Therefore, as the Earth turns, stars appear to revolve around Polaris, but Polaris itself always stays in the same northerly direction -- making it the North Star.  Since no bright star is near the south spin axis of the Earth, there is currently no bright South Star.  Thousands of years ago, Earth's spin axis pointed in a slightly different direction so that Vega was the North Star.  Although Polaris is not the brightest star on the sky, it is easily located because it is nearly aligned with two stars in the cup of the Big Dipper. Polaris is near the center of the five-degree wide featured image, a digital composite of hundreds of exposures that brings out faint gas and dust of the Integrated Flux Nebula (IFN) all over the frame. The surface of Cepheid Polaris slowly pulsates, causing the famous star to change its brightness by a few percent over the course of a few days.    Today: Zoom APOD Lecture hosted by the Amateur Astronomers of Association of New York

Image credit: Davide Coverta
Wolf Moon Engulfs Mars (2025-01-15)

Does the Moon ever engulf Mars? Yes, but only in the sense that it moves in front, which happens on rare occasions.  This happened just yesterday, though, as seen from some locations in North America and western Africa.  This occultation was notable not only because the Moon was a fully lit Wolf Moon, but because Mars was near its largest and brightest, moving to opposition -- the closest to the Earth in its orbit -- only tomorrow.  The engulfing, more formally called an occultation, typically lasts about an hour. The featured image was taken from near Chicago, Illinois, USA just as Earth's largest satellite was angularly moving away from the much more distant red planet. Our  Moon occasionally moves in front of all of the Solar System's planets.  Given the temporary alignment of orbital planes, the next time our Moon eclipses Mars will be a relatively soon February 9.   Growing Gallery: Moon-Mars Occultation in January 2025

Image credit: Imran Sultan
M83: The Southern Pinwheel (2025-01-16)

Beautiful and bright spiral galaxy M83 lies a some twelve million light-years away, near the southeastern tip of the very long constellation Hydra. Prominent spiral arms traced by dark dust lanes and blue star clusters lend this galaxy its popular name, The Southern Pinwheel.  Still, reddish star forming regions that dot this cosmic pinwheel's spiral arms have suggested another nickname, the Thousand-Ruby Galaxy. A mere 40,000 light-years across, smaller than the Milky Way, M83 is a member of a group of galaxies that includes active galaxy Centaurus A. In fact, the core of M83 itself is bright at x-ray energies, showing a high concentration of neutron stars and black holes left from an intense burst of star formation. This sharp color image also features spiky foreground Milky Way stars and distant background galaxies. The image data was captured with the Dark Energy Camera and Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory.
Supernova Remnant Cassiopeia A (2025-01-17)

Massive stars in our Milky Way Galaxy live spectacular lives.  Collapsing from vast cosmic clouds, their nuclear furnaces ignite and create heavy elements in their cores. After only a few million years for the most massive stars, the enriched material is blasted back into interstellar space where star formation can begin anew. The expanding debris cloud known as Cassiopeia A is an example of this final phase of the stellar life cycle. Light from the supernova explosion that created this remnant would have been first seen in planet Earth's sky about 350 years ago, although it took that light 11,000 years to reach us. This sharp NIRCam image from the James Webb Space Telescope shows the still hot filaments and knots in the supernova remnant. The whitish, smoke-like outer shell of the expanding blast wave is about 20 light-years across. A series of light echoes from the massive star's cataclysmic explosion are also identified in Webb's detailed images of the surrounding interstellar medium.
Full Moon, Full Mars (2025-01-18)

On January 13 a Full Moon and a Full Mars were close, both bright and opposite the Sun in planet Earth's sky. In fact Mars was occulted, passing behind the Moon, when viewed from some locations in North America and northwest Africa.  As seen from Richmond, Virginia, USA, this composite image sequence follows the evening lunar occultation before, during, and after the much anticipated celestial spectacle. The telescopic time series is constructed from an exposure made every two minutes while tracking the Moon over the hours encompassing the event. As a result, the Red Planet's trajectory seems to follow a gently curved path due to the Moon's slightly different rate of apparent motion. The next lunar occultation of bright planet Mars will be on February 9 when the moon is in a waxing gibbous phase. Lunar occultations are only ever visible from a fraction of the Earth's surface, though. The February 9 occultation of Mars will be seen from parts of Russia, China, eastern Canada, Greenland and other (mostly northern) locations, but a close conjunction of a bright Moon with Mars will be more widely visible from planet Earth.   Growing Gallery: Moon-Mars Occultation in January 2025

Image credit: David Bowman