juliensimon/nasa-apod huggingface dataset:
Moon Rising Between Starships (2021-02-22)

What's that on either side of the Moon? Starships. Specifically, they are launch-and-return reusable rockets being developed by SpaceX to lift cargo and eventually humans from the Earth's surface into space.  The two rockets pictured are SN9 (Serial Number 9) and SN10 which were captured near their Boca Chica, Texas launchpad last month posing below January's full Wolf Moon. The Starships house liquid-methane engines inside rugged stainless-steel shells. SN9 was test-launched earlier this month and did well with the exception of one internal rocket that failed to relight during powered descent.  SN10 continues to undergo ground tests and may be test-launched later this month.

Image credit: John Kraus
Video: Perseverance Landing on Mars (2021-02-23)

What would it look like to land on Mars?  To better monitor the instruments involved in the Entry, Decent, and Landing of the Perseverance Rover on Mars last week, cameras with video capability were included that have now returned their images. The featured 3.5-minute composite video begins with the opening of a huge parachute that dramatically slows the speeding spacecraft as it enters the Martian atmosphere.  Next the heat shield is seen separating and falls ahead. As Perseverance descends, Mars looms large and its surface becomes increasingly detailed.  At just past 2-minutes into the video, the parachute is released and Perseverance begins to land with dust-scattering rockets. Soon the Sky Crane takes over and puts Perseverance down softly, then quickly jetting away. The robotic Perseverance rover will now begin exploring ancient Jezero Crater, including a search for signs that life once existed on Earth's neighboring planet.
Spiral Galaxy M66 from Hubble (2021-02-24)

It’s always nice to get a new view of an old friend.  This stunning Hubble Space Telescope image of nearby spiral galaxy M66 is just that.  A spiral galaxy with a small central bar, M66 is a member of the Leo Galaxy Triplet, a group of three galaxies about 30 million light years from us.  The Leo Triplet is a popular target for relatively small telescopes, in part because M66 and its galactic companions M65 and NGC 3628 all appear separated by about the angular width of a full moon.  The featured image of M66 was taken by Hubble to help investigate the connection between star formation and molecular gas clouds.  Clearly visible are bright blue stars, pink ionized hydrogen clouds -- sprinkled all along the outer spiral arms, and dark dust lanes in which more star formation could be hiding.
A Venus Flyby (2021-02-25)

On a mission to explore the inner heliosphere and solar corona, on July 11, 2020 the Wide-field Imager on board NASA's Parker Solar Probe captured this stunning view of the nightside of Venus at distance of about 12,400 kilometers (7,693 miles). The spacecraft was making the third of seven gravity-assist flybys of the inner planet. The gravity-asssist flybys are designed to use the approach to Venus to help the probe alter its orbit to ultimately come within 6 million kilometers (4 million miles) of the solar surface in late 2025. A surprising image, the side-looking camera seems to peer through the clouds to show a dark feature near the center known as Aphrodite Terra, the largest highland region on the Venusian surface. The bright rim at the edge of the planet is nightglow likely emitted by excited oxygen atoms recombining into molecules in the upper reaches of the atmosphere. Bright streaks and blemishes throughout the image are likely due to energetic charged particles, and dust near the camera reflecting sunlight. Skygazers from planet Earth probably recognize the familiar stars of Orion's belt and sword at lower right.
Mars Perseverance Sol 3 (2021-02-26)

Stitched together on planet Earth, 142 separate images make up this 360 degree panorama from the floor of Jezero Crater on Mars. The high-resolution color images were taken by the Perseverance rover's zoomable Mastcam-Z during mission sol 3, also known as February 21, 2021. In the foreground of Mastcam-Z's view is the car-sized rover's deck. Broad light-colored patches in the martian soil just beyond it were scoured by descent stage rocket engines during the rover's dramatic arrival on February 18. The rim of 45 kilometer-wide Jezero Crater rises in the distance. In the coming sols, Perseverance will explore the ancient lake-delta system in the crater, hunting for signs of past microscopic life and collecting samples for potential future return to planet Earth.
Perseverance Landing Site from Mars Reconnaissance Orbiter (2021-02-27)

Seen from orbit a day after a dramatic arrival on the martian surface, the Perseverance landing site is identified in this high-resolution view from the Mars Reconnaissance Orbiter. The orbiter's camera image also reveals the location of the Mars 2020 mission descent stage, heat shield, and parachute and back shell that delivered Perseverance to the surface of Mars.  Each annotated inset box spans 200 meters (650 feet) across the floor of Jezero Crater. Perseverance is located at the center of the pattern created by rocket exhaust as the descent stage hovered and lowered the rover to the surface. Following the sky crane maneuver, the descent stage itself flew away to crash at a safe distance from the rover, its final resting place indicated by a dark V-shaped debris pattern. Falling to the surface nearby after their separation in the landing sequence, heat shield, parachute and back shell locations are marked in the high-resolution image from Mars orbit.
The Aurora Tree (2021-02-28)

Yes, but can your tree do this?  Pictured is a visual coincidence between the dark branches of a nearby tree and bright glow of a distant aurora. The beauty of the aurora -- combined with how it seemed to mimic a tree right nearby -- mesmerized the photographer to such a degree that he momentarily forgot to take pictures. When viewed at the right angle, it seemed that this tree had aurora for leaves. Fortunately, before the aurora morphed into a different overall shape, he came to his senses and capture the awe-inspiring momentary coincidence.  Typically triggered by solar explosions, aurora are caused by high energy electrons impacting the Earth's atmosphere around 150 kilometers up.  The unusual Earth-sky collaboration was witnessed in March of 2017 in Iceland.    Almost Hyperspace: Random APOD Generator

Image credit: Alyn Wallace
The Pelican Nebula in Red and Blue (2021-03-01)

The Pelican Nebula is changing.   The entire nebula, officially designated IC 5070, is divided from the larger North America Nebula by a molecular cloud filled with dark dust.  The Pelican, however, is particularly interesting because it is an unusually active mix of star formation and evolving gas clouds.  The featured picture was processed to bring out two main colors, red and blue, with the red dominated by light emitted by interstellar hydrogen. Ultraviolet light emitted by young energetic stars is slowly transforming cold gas in the nebula to hot gas, with the advancing boundary between the two, known as an ionization front, visible in bright red across the image center. Particularly dense tentacles of cold gas remain.  Millions of years from now this nebula might no longer be known as the Pelican, as the balance and placement of stars and gas will surely leave something that appears completely different.   APOD in world languages: Arabic, Bulgarian, Catalan, Chinese (Beijing), Chinese (Taiwan), Croatian, Czech, Dutch, Farsi, French, German, Hebrew, Indonesian, Korean, Montenegrin, Polish, Russian, Serbian, Slovenian,  Spanish, Taiwanese, Turkish, Turkish, and  Ukrainian

Image credit: U. Mishra
Ingenuity: A Mini-Helicopter Now on Mars (2021-03-02)

What if you could fly around Mars?  NASA may have achieved that capability last month with the landing of Perseverance, a rover which included a small flight-worthy companion called Ingenuity, nicknamed Ginny. Even though Ginny is small -- a toaster-sized helicopter with four long legs and two even-longer (1.2-meter) rotors, she is the first of her kind -- there has never been anything like her before.  After being deployed, possibly in April, the car-sized Perseverance ("Percy") will back away to give Ginny ample room to attempt her unprecedented first flight.  In the featured artistic illustration, Ginny's long rotors are depicted giving her the lift she needs to fly into the thin Martian atmosphere and explore the area near Perseverance.  Although Ingenuity herself will not fly very far, she is a prototype for all future airborne Solar-System robots that may fly far across not only Mars, but Titan.
Stars over an Erupting Volcano (2021-03-03)

Mt. Etna has been erupting for hundreds of thousands of years.  Located in Sicily, Italy, the volcano produces lava fountains over one kilometer high.  Mt. Etna is not only one of the most active volcanoes on Earth, it is one of the largest, measuring over 50 kilometers at its base and rising nearly 3 kilometers high.  Pictured erupting last month,  a lava plume shoots upwards, while hot lava flows down the volcano's exterior. Likely satellite trails appear above, while ancient stars dot the sky far in the distance.  This volcanic eruption was so strong that nearby airports were closed to keep planes from flying through the dangerous plume.  The image foreground and background were captured consecutively by the same camera and from the same location.    Please take a short survey in aesthetics & astronomy: Sonification

Image credit: Giuseppe Vella
Mars in Taurus (2021-03-04)

You can spot Mars in the evening sky tonight. Now home to the Perseverance rover, the Red Planet is presently wandering through the constellation Taurus, close on the sky to the Seven Sisters or Pleiades star cluster. In fact this deep, widefield view of the region captures Mars near its closest conjunction to the Pleiades on March 3. Below center, Mars is the bright yellowish celestial beacon only about 3 degrees from the pretty blue star cluster. Competing with Mars in color and brightness, Aldebaran is the alpha star of Taurus. The red giant star is toward the lower left edge of the frame, a foreground star along the line-of-sight to the more distant Hyades star cluster. Otherwise too faint for your eye to see, the dark, dusty nebulae lie along the edge of the massive Perseus molecular cloud, with the striking reddish glow of NGC 1499, the California Nebula, at the upper right.   Please take a short survey in aesthetics & astronomy: Sonification

Image credit: Petr Horalek
A Little Like Mars (2021-03-05)

The surface of this planet looks a little like Mars. It's really planet Earth though. In a digitally stitched little planet projection, the 360 degree mosaic was captured near San Pedro in the Chilean Atacama desert. Telescopes in domes on the horizon are taking advantage of the arid region's famously dark, clear nights. Taken in early December, a magnificent Milky Way arcs above the horizon for almost 180 degrees around the little planet with Orion prominent in the southern sky. A familiar constellation upside down for northern hemisphere skygazers, Orion shares that southern December night almost opposite the Large and Small Magellanic clouds. But the Red Planet itself is the brightest yellowish celestial beacon in this little planet sky.   Please take a short survey in aesthetics & astronomy: Sonification

Image credit: Robert Barsa
Perseverance Takes a Spin (2021-03-06)

After arriving at Jezero Crater on Mars, Perseverance went for a spin on March 4. This sharp image from the car-sized rover's Navcam shows tracks left by its six wheels in the martian soil. In preparation for operations on the surface of the Red Planet, its first drive lasted about 33 minutes. On a short and successful test drive Perseverance moved forward 4 meters, made a 150 degree turn in place, backed up for 2.5 meters, and now occupies a different parking space at its newly christened Octavia E. Butler Landing location. Though the total travel distance of the rover's first outing was about 6.5 meters (21 feet), regular commutes of 200 meters or more can be expected in the future.   Please take a short survey in aesthetics & astronomy: Sonification
Pillars of the Eagle Nebula in Infrared (2021-03-07)

Newborn stars are forming in the Eagle Nebula.  Gravitationally contracting in pillars of dense gas and dust, the intense radiation of these newly-formed bright stars is causing surrounding material to boil away. This image, taken with the Hubble Space Telescope in near infrared light, allows the viewer to see through much of the thick dust that makes the pillars opaque in visible light.  The giant structures are light years in length and dubbed informally the Pillars of Creation.  Associated with the open star cluster M16, the Eagle Nebula lies about 6,500 light years away.  The Eagle Nebula is an easy target for small telescopes in a nebula-rich part of the sky toward the split constellation Serpens Cauda (the tail of the snake).
Three Tails of Comet NEOWISE (2021-03-08)

What created the unusual red tail in Comet NEOWISE? Sodium.  A spectacular sight back in the summer of 2020, Comet NEOWISE, at times, displayed something more than just a surprisingly striated white dust tail and a pleasingly patchy blue ion tail. Some color sensitive images showed an unusual red tail, and analysis showed much of this third tail's color was emitted by sodium.  Gas rich in sodium atoms might have been liberated from Comet NEOWISE's warming nucleus in early July by bright sunlight, electrically charged by ultraviolet sunlight, and then pushed out by the solar wind. The featured image was captured in mid-July from Brittany, France and shows the real colors. Sodium comet tails have been seen before but are rare -- this one disappeared by late July.  Comet C/2020 F3 (NEOWISE) has since faded, lost all of its bright tails, and now approaches the orbit of Jupiter as it heads back to the outer Solar System, to return only in about 7,000 years.    Astrophysicists: Browse 2,400+ codes in the Astrophysics Source Code Library

Image credit: Nicolas Lefaudeux
Perseverance 360: Unusual Rocks and the Search for Life on Mars (2021-03-09)

Is that a fossil?  Looking through recent images of Mars taken by the new Perseverance rover may seem a bit like treasure hunting, with the possibility of fame coming to the first person to correctly identify a petrified bone, a rock imprinted by an ancient plant, or any clear indication that life once existed on Mars.  Unfortunately, even though it is possible that something as spectacular as a skeleton could be identified, most exobiologists think it much more likely that biochemical remnants of ancient single-celled microbes could be found with Perseverance's chemical analyzers.  A key reason is that multicellular organisms may take a greater amount of oxygen to evolve than has ever been present on Mars. That said, nobody's sure, so please feel free to digitally magnify any Perseverance image that interests you -- including the featured 360-degree zoomable image of the rocks and ridges surrounding Perseverance's landing location in Jezero Crater.  And even though NASA-affiliated scientists are themselves studying Perseverance's images, if you see anything really unusual, please post it to popular social media. If your sighting turns out to be particularly intriguing, scientifically, it is likely that NASA will hear about it.
NGC 1499: The California Nebula (2021-03-10)

Could Queen Calafia's mythical island exist in space? Perhaps not, but by chance the outline of this molecular space cloud echoes the outline of the state of California, USA. Our Sun has its home within the Milky Way's Orion Arm, only about 1,000 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. On the featured image, the most prominent glow of the California Nebula is the red light characteristic of hydrogen atoms recombining with long lost electrons, stripped away (ionized) by energetic starlight. The star most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot, bluish Xi Persei just to the right of the nebula.  A regular target for astrophotographers, the California Nebula can be spotted with a wide-field telescope under a dark sky toward the constellation of Perseus, not far from the Pleiades.   New: APOD now available in Arabic from Syria

Image credit: Yannick Akar
Zodiacal Light and Mars (2021-03-11)

Just after sunset on March 7, a faint band of light still reaches above the western horizon in this serene, rural Illinois, night skyscape. Taken from an old farmstead, the luminous glow is zodiacal light, prominent in the west after sunset during planet Earth's northern hemisphere spring. On that clear evening the band of zodiacal light seems to engulf bright yellowish Mars and the Pleiades star cluster. Their close conjunction is in the starry sky above the old barn's roof. Zodiacal light is sunlight scattered by interplanetary dust particles that lie near the Solar System's ecliptic plane. Of course all the Solar System's planets orbit near the plane of the ecliptic, within the band of zodiacal light. But zodiacal light and Mars may have a deeper connection. A recent analysis of serendipitous detections of interplanetary dust by the Juno spacecraft during its Earth to Jupiter voyage suggest Mars is the likely source of the dust that produces zodiacal light.

Image credit: Joshua Rhoades
Messier 81 (2021-03-12)

One of the brightest galaxies in planet Earth's sky is similar in size to our Milky Way Galaxy: big, beautiful Messier 81. Also known as NGC 3031 or Bode's galaxy for its 18th century discoverer, this grand spiral can be found toward the northern constellation of Ursa Major, the Great Bear. The sharp, detailed telescopic view reveals M81's bright yellow nucleus, blue spiral arms, pinkish starforming regions, and sweeping cosmic dust lanes. Some dust lanes actually run through the galactic disk (left of center), contrary to other prominent spiral features though. The errant dust lanes may be the lingering result of a close encounter between M81 and the nearby galaxy M82 lurking outside of this frame. M81's faint, dwarf irregular satellite galaxy, Holmberg IX, can be seen just below the large spiral. Scrutiny of variable stars in M81 has yielded a well-determined distance for an external galaxy -- 11.8 million light-years.

Image credit: Wissam Ayoub
SuperCam Target on Ma'az (2021-03-13)

What's the sound of one laser zapping? There's no need to consult a Zen master to find out, just listen to the first acoustic recording of laser shots on Mars. On Perseverance mission sol 12 (March 2) the SuperCam instrument atop the rover's mast zapped a rock dubbed Ma'az 30 times from a range of about 3.1 meters. Its microphone recorded the soft staccato popping sounds of the rapid series of SuperCam laser zaps. Shockwaves created in the thin martian atmosphere as bits of rock are vaporized by the laser shots make the popping sounds, sounds that offer clues to the physical structure of the target. This SuperCam close-up of the Ma'az target region is 6 centimeters (2.3 inches) across. Ma'az means Mars in the Navajo language.
A Flag Shaped Aurora over Sweden (2021-03-14)

It appeared, momentarily, like a 50-km tall banded flag.  In mid-March of 2015, an energetic Coronal Mass Ejection directed toward a clear magnetic channel to Earth led to one of the more intense geomagnetic storms of recent years. A visual result was wide spread auroras being seen over many countries near Earth's magnetic poles.  Captured over Kiruna, Sweden, the image features an unusually straight auroral curtain with the green color emitted low in the Earth's atmosphere, and red many kilometers higher up. It is unclear where the rare purple aurora originates, but it might involve an unusual blue aurora at an even lower altitude than the green, seen superposed with a much higher red.  Now past Solar Minimum, colorful nights of auroras over Earth are likely to increase.   Follow APOD: Through the Free NASA App

Image credit: Mia Stålnacke
Meteor Fireballs in Light and Sound (2021-03-15)

Yes, but have you ever heard a meteor? Usually, meteors are too far away to make any audible sound.  However, a meteor will briefly create an ionization trail that can reflect a distant radio signal. If the geometry is right, you may momentarily hear -- through your radio -- a distant radio station even over static.  In the featured video, the sounds of distant radio transmitters were caught reflecting from large meteor trails by a sensitive radio receiver -- at the same time the bright streaks were captured by an all-sky video camera. In the video, the  bright paths taken by four fireballs across the sky near Lamy, New Mexico, USA, are shown first.  Next, after each static frame, a real-time video captures each meteor streaking across the sky, now paired with the sound recorded from its radio reflection.  Projecting a meteor trail down to the Earth may lead to finding its impact site (if any), while projecting its trail back into the sky may lead to identifying its parent comet or asteroid.   Almost Hyperspace: Random APOD Generator

Image credit: Thomas Ashcraft 
(Radio Fireball Observatory)
IC 1318: The Butterfly Nebula in Gas and Dust (2021-03-16)

In the constellation of the swan near the nebula of the pelican lies the gas cloud of the butterfly next to a star known as the hen.  That star, given the proper name Sadr, is just to the right of the featured frame, but the central Butterfly Nebula, designated IC 1318, is shown in high resolution. The intricate patterns in the bright gas and dark dust are caused by complex interactions between interstellar winds, radiation pressures, magnetic fields, and gravity. The featured telescopic view captures IC 1318's characteristic emission from ionized sulfur, hydrogen, and oxygen atoms mapped to the red, green, and blue hues of the popular Hubble Palette. The portion of the Butterfly Nebula pictured spans about 100 light years and lies about 4000 light years away.

Image credit: Alan Pham
The Surface of Venus from Venera 14 (2021-03-17)

If you could stand on Venus -- what would you see?  Pictured is the view from Venera 14, a robotic Soviet lander which parachuted and air-braked down through the thick Venusian atmosphere in March of 1982. The desolate landscape it saw included flat rocks, vast empty terrain, and a featureless sky above Phoebe Regio near Venus' equator. On the lower left is the spacecraft's penetrometer used to make scientific measurements, while the light piece on the right is part of an ejected lens-cap.  Enduring temperatures near 450 degrees Celsius and pressures 75 times that on Earth, the hardened Venera spacecraft lasted only about an hour. Although data from Venera 14 was beamed across the inner Solar System almost 40 years ago, digital processing and merging of Venera's unusual images continues even today.  Recent analyses of infrared measurements taken by ESA's orbiting Venus Express spacecraft indicate that active volcanoes may currently exist on Venus.

Image credit: Donald Mitchell
Stardust in the Perseus Molecular Cloud (2021-03-18)

Clouds of stardust drift through this deep skyscape, across the Perseus molecular cloud some 850 light-years away. Dusty nebulae reflecting light from embedded young stars stand out in the nearly 2 degree wide telescopic field of view. With a characteristic bluish color reflection nebula NGC 1333 is at center, vdB 13 at top right, with rare yellowish reflection nebula vdB 12 near the top of the frame. Stars are forming in the molecular cloud, though most are obscured at visible wavelengths by the pervasive dust. Still, hints of contrasting red emission from Herbig-Haro objects, the jets and shocked glowing gas emanating from recently formed stars, are evident in NGC 1333. The chaotic environment may be similar to one in which our own Sun formed over 4.5 billion years ago. At the estimated distance of the Perseus molecular cloud, this cosmic scene would span about 40 light-years.

Image credit: Kerry-Ann Lecky Hepburn