How does your favorite planet spin? Does it spin rapidly around a nearly vertical axis, or horizontally, or backwards? The featured video animates NASA images of all eight planets in our Solar System to show them spinning side-by-side for an easy comparison. In the time-lapse video, a day on Earth -- one Earth rotation -- takes just a few seconds. Jupiter rotates the fastest, while Venus spins not only the slowest (can you see it?), but backwards. The inner rocky planets across the top underwent dramatic spin-altering collisions during the early days of the Solar System. Why planets spin and tilt as they do remains a topic of research with much insight gained from modern computer modeling and the recent discovery and analysis of hundreds of exoplanets: planets orbiting other stars.

https://apod.nasa.gov/apod/ap250914.html ( September 14, 2025)

The steerable 60 foot diameter dish antenna of the One-Mile Telescope at Mullard Radio Astronomy Observatory, Cambridge, UK, is pointing skyward in this evocative night-skyscape. To capture the dramatic scene, consecutive 30 second exposures were recorded over a period of 90 minutes. Combined, the exposures reveal a background of gracefully arcing star trails that reflect planet Earth's daily rotation on its axis. The North Celestial Pole, the extension of Earth's axis of rotation into space, points near Polaris, the North Star. That's the bright star that creates the short trail near the center of the concentric arcs. But the historic One-Mile Telescope array also relied on planet Earth's rotation to operate. Exploring the universe at radio wavelengths, it was the first radio telescope to use Earth-rotation aperture synthesis. That technique uses the rotation of the Earth to change the relative orientation of the telescope array and celestial radio sources to create radio maps of the sky at a resolution better than that of the human eye.

https://apod.nasa.gov/apod/ap250913.html ( September 13, 2025)

September's total lunar eclipse is tracked across night skies from both the northern and southern hemispheres of planet Earth in these two dramatic timelapse series. In the northern hemisphere sequence (top panel) the Moon’s trail arcs from the upper left to the lower right. It passes below bright planet Saturn, seen under mostly clear skies from the international campus of Zhejiang University in China at about 30 degrees north latitude. In contrast, the southern hemisphere view from Lake Griffin, Canberra, Australia at 35 degrees south latitude, records the Moon’s trail from the upper right to the lower left. Multiple lightning flashes from thunderstorms near the horizon appear reflected in the lake. Both sequences were photographed with 16mm wide-angle lenses and both cover the entire eclipse, with the darkened red Moon totally immersed in Earth's umbral shadow near center. But the different orientations of the Moon’s path across the sky reveal the perspective shifts caused by the views from northern vs. southern latitudes.

https://apod.nasa.gov/apod/ap250912.html ( September 12, 2025)

The dark, inner shadow of planet Earth is called the umbra. Shaped like a cone extending into space, it has a circular cross section most easily seen during a lunar eclipse. And on the night of September 7/8 the Full Moon passed near the center of Earth's umbral cone, entertaining eclipse watchers around much of our fair planet, including parts of Antarctica, Australia, Asia, Europe, and Africa. Recorded from Zhangjiakou City, China, this timelapse composite image uses successive pictures from the total lunar eclipse, progressing left to right, to reveal the curved cross-section of the umbral shadow sliding across the Moon. Sunlight scattered by the atmosphere into Earth's umbra causes the lunar surface to appear reddened during totality. But close to the umbra's edge, the limb of the eclipsed Moon shows a distinct blue hue. The blue eclipsed moonlight originates as rays of sunlight pass through layers high in the upper stratosphere, colored by ozone that scatters red light and transmits blue. In the total phase of this leisurely lunar eclipse, the Moon was completely within the Earth's umbra for about 83 minutes.

https://apod.nasa.gov/apod/ap250911.html ( September 11, 2025)

It is one of the largest nebulas on the sky -- why isn't it better known? Roughly the same angular size as the Andromeda Galaxy, the Great Lacerta Nebula can be found toward the constellation of the Lizard (Lacerta). The emission nebula is difficult to see with wide-field binoculars because it is so faint, but also usually difficult to see with a large telescope because it is so great in angle -- spanning about three degrees. The depth, breadth, waves, and beauty of the nebula -- cataloged as Sharpless 126 (Sh2-126) -- can best be seen and appreciated with a long duration camera exposure. The featured image is one such combined exposure -- in this case taken over three nights in August through dark skies in Moses Lake, Washington, USA. The hydrogen gas in the Great Lacerta Nebula glows red because it is excited by light from the bright star 10 Lacertae, one of the bright blue stars just to the left of the red-glowing nebula's center. Most of the stars and nebula are about 1,200 light years distant.

https://apod.nasa.gov/apod/ap250910.html ( September 10, 2025)

What's that rising up from the Earth? When circling the Earth on the International Space Station early in July, astronaut Nicole Ayers saw an unusual type of lightning rising up from the Earth: a gigantic jet. The powerful jet appears near the center of the featured image in red, white, and blue. Giant jet lightning has only been known about for the past 25 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 remain active topics of research.

https://apod.nasa.gov/apod/ap250909.html ( September 09, 2025)

This butterfly can hatch planets. The nebula fanning out from the star IRAS 04302+2247 may look like the wings of a butterfly, while the vertical brown stripe down the center may look like the butterfly's body -- but together they indicate an active planet-forming system. The featured picture was captured recently in infrared light by the Webb Space Telescope. Pictured, the vertical disk is thick with the gas and dust from which planets form. The disk shades visible and (most) infrared light from the central star, allowing a good view of the surrounding dust that reflects out light. In the next few million years, the dust disk will likely fragment into rings through the gravity of newly hatched planets. And a billion years from now, the remaining gas and dust will likely dissipate, leaving mainly the planets -- like in our Solar System.

https://apod.nasa.gov/apod/ap250908.html ( September 08, 2025)

How much of planet Earth is made of water? Very little, actually. Although oceans of water cover about 70 percent of Earth's surface, these oceans are shallow compared to the Earth's radius. The featured illustration shows what would happen if all of the water on or near the surface of the Earth were bunched up into a ball. The radius of this ball would be only about 700 kilometers, less than half the radius of the Earth's Moon, but slightly larger than Saturn's moon Rhea which, like many moons in our outer Solar System, is mostly water ice. The next smallest ball depicts all of Earth's liquid fresh water, while the tiniest ball shows the volume of all of Earth's fresh-water lakes and rivers. How any of this water came to be on the Earth and whether any significant amount is trapped far beneath Earth's surface remain topics of research.

https://apod.nasa.gov/apod/ap250907.html ( September 07, 2025)

When the sun sets on September 7, the Full Moon will rise. And on that date denizens around much of our fair planet, including parts of Antarctica, Australia, Asia, Europe, and Africa can witness a total lunar eclipse, with the Moon completely immersed in Earth's shadow. As the bright Full Moon first enters Earth's shadow it will darken, finally taking on a reddish hue during the total eclipse phase. In fact, the color of the Moon during a total lunar eclipse is due to reddened light from sunrises and sunsets around planet Earth. The reddened sunlight is scattered by a dense atmosphere into the planet's otherwise dark central shadow. When the sun set on August 22, this telephoto snapshot of red skies, blue sea, and the Mangiabarche Lighthouse was captured from Sant'Antioco, Sardinia, Italy.

https://apod.nasa.gov/apod/ap250906.html ( September 06, 2025)

Also known as NGC 104, 47 Tucanae is a jewel of the southern sky. Not a star but a dense cluster of stars, it roams the halo of our Milky Way Galaxy along with some 200 other globular star clusters. The second brightest globular cluster (after Omega Centauri) as seen from planet Earth, 47 Tuc lies about 13,000 light-years away. It can be spotted with the naked eye close on the sky to the Small Magellanic Cloud in the constellation of the Toucan. The dense cluster is made up of hundreds of thousands of stars in a volume only about 120 light-years across. Red giant stars on the outskirts of the cluster are easy to pick out as yellowish stars in this sharp telescopic portrait. Tightly packed globular star cluster 47 Tuc is also home to a star with the closest known orbit around a black hole.

https://apod.nasa.gov/apod/ap250905.html ( September 05, 2025)

Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices. This sharp, colorful image reveals the galaxy's boxy, bulging central core cut by obscuring dust lanes that lace NGC 4565's thin galactic plane. NGC 4565 lies around 40 million light-years distant while the spiral galaxy itself spans some 100,000 light-years. That's about the size of our own Milky Way. Easily spotted with small telescopes, deep sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed.

https://apod.nasa.gov/apod/ap250904.html ( September 04, 2025)

How soon do jets form when a supernova gives birth to a neutron star? The Africa Nebula provides clues. This supernova remnant surrounds Circinus X-1, an X-ray emitting neutron star and the companion star it orbits. The image, from the ThunderKAT collaboration on the MeerKAT radio telescope situated in South Africa, shows the bright core-and-lobe structure of Cir X-1’s currently active jets inside the nebula. A mere 4600 years old, Cir X-1 could be the "Little Sister" of microquasarSS 433*. However, the newly discovered bubble exiting from a ring-like hole in the upper right of the nebula, along with a ring to the bottom left, demonstrate that other jets previously existed. Computer simulations indicate those jets formed within 100 years of the explosion and lasted up to 1000 years. Surprisingly, to create the observed bubble, the jets need to be more powerful than young neutron stars were previously thought to produce.

https://apod.nasa.gov/apod/ap250903.html ( September 03, 2025)

The Horsehead Nebula is one of the most famous nebulae on the sky. It is visible as the dark indentation to the orange emission nebula at the far right of the featured picture. The horse-head feature is dark because it is really an opaque dust cloud that lies in front of the bright emission nebula. Like clouds in Earth's atmosphere, this cosmic cloud has assumed a recognizable shape by chance. After many thousands of years, the internal motions of the cloud will surely alter its appearance. The emission nebula's orange color is caused by electrons recombining with protons to form hydrogen atoms. Toward the lower left of the image is the Flame Nebula, an orange-tinged nebula that also contains intricate filaments of dark dust.

https://apod.nasa.gov/apod/ap250902.html ( September 02, 2025)

Its surface is the most densely cratered in the Solar System -- but what's inside? Jupiter's moon Callisto is a battered ball of dirty ice that is larger than the planet Mercury. It was visited by NASA's Galileo spacecraft in the 1990s and 2000s, but the recently reprocessed featured image is from a flyby of NASA's Voyager 2 in 1979. The moon would appear darker if it weren't for the tapestry of light-colored fractured surface ice created by eons of impacts. The interior of Callisto is potentially even more interesting because therein might lie an internal layer of liquid water. This potential underground sea is a candidate to harbor life -- similar with sister moons Europa and Ganymede. Callisto is slightly larger than Luna, Earth's Moon, but because of its high ice content is slightly less massive. ESA's JUICE and NASA's Europa Clipper missions are now headed out to Jupiter to better investigate its largest moons.

https://apod.nasa.gov/apod/ap250901.html ( September 01, 2025)

What created this unusual planetary nebula? Dubbed the Pillow Nebula and the Flying Carpet Nebula, NGC 7027 is one of the smallest, brightest, and most unusually shaped planetary nebulas known. Given its expansion rate, NGC 7027 first started expanding, as visible from Earth, about 600 years ago. For much of its history, the planetary nebula has been expelling shells, as seen in blue in the featured image by the Hubble Space Telescope. In modern times, though, for reasons unknown, it began ejecting gas and dust (seen in brown) in specific directions that created a new pattern that seems to have four corners. What lies at the nebula's center is unknown, with one hypothesis holding it to be a close binary star system where one star sheds gas onto an erratic disk orbiting the other star. NGC 7027, about 3,000 light years away, was first discovered in 1878 and can be seen with a standard backyard telescope toward the constellation of the Swan (Cygnus).

https://apod.nasa.gov/apod/ap250831.html ( August 31, 2025)

A young crescent moon can be hard to see. That's because when the Moon shows it's crescent phase (young or old) it can never be far from the Sun in planet Earth's sky. And even though the sky is still bright, a slender sunlit lunar crescent is cleary visible in this early evening skyscape. The telephoto snapshot was captured on August 24, with the Moon very near the western horizon at sunset. Seen in a narrow crescent phase about 1.5 days old, the visible sunlit portion is a mere two percent of the surface of the Moon's familiar nearside. At the Canary Islands Space Centre, a steerable radio dish for communication with spacecraft is titled in the direction of the two percent Moon. The sunset sky's pastel pinkish coloring is partly due to fine sand and dust from the Sahara Desert blown by the prevailing winds.

https://apod.nasa.gov/apod/ap250830.html ( August 30, 2025)

The diffuse hydrogen-alpha glow of emission region Sh2-27 fills this cosmic scene. The field of view spans nearly 3 degrees across the nebula-rich constellation Ophiuchus toward the central Milky Way. A Dark Veil of wispy interstellar dust clouds draped across the foreground is chiefly identified as LDN 234 and LDN 204 from the 1962 Catalog of Dark Nebulae by American astronomer Beverly Lynds. Sh2-27 itself is the large but faint HII region surrounding runaway O-type star Zeta Ophiuchi. Along with the Zeta Oph HII region, LDN 234 and LDN 204 are likely 500 or so light-years away. At that distance, this telescopic frame would be about 25 light-years wide.

https://apod.nasa.gov/apod/ap250829.html ( August 29, 2025)

This well-composed telescopic field of view covers over a Full Moon on the sky toward the high-flying constellation Pegasus. Of course the brighter stars show diffraction spikes, the commonly seen effect of internal supports in reflecting telescopes, and lie well within our own Milky Way galaxy. The faint but pervasive clouds of interstellar dust ride above the galactic plane and dimly reflect the Milky Way's starlight. Known as galactic cirrus or integrated flux nebulae they are associated with the Milky Way's molecular clouds. In fact, the diffuse cloud cataloged as MBM 54, less than a thousand light-years distant, fills the scene. The galaxy seemingly tangled in the dusty cloud is the striking spiral galaxy NGC 7497. It's some 60 million light-years away, though. Seen almost edge-on near the center of the field, NGC 7497's own spiral arms and dust lanes echo the colors of stars and dust in our own Milky Way.

https://apod.nasa.gov/apod/ap250828.html ( August 28, 2025)

That yellow spot -- what is it? It's a young planet outside our Solar System. The featured image from the Very Large Telescope in Chile surprisingly captures a distant scene much like our own Solar System's birth, some 4.5 billion years ago. Although we can't look into the past and see Earth's formation directly, telescopes let us watch similar processes unfolding around distant stars. At the center of this frame lies a young Sun-like star, hidden behind a coronagraph that blocks its bright glare. Surrounding the star is a bright, dusty protoplanetary disk -- the raw material of planets. Gaps and concentric rings mark where a newborn world is gathering gas and dust under its gravity, clearing the way as it orbits the star. Although astronomers have imaged disk-embedded planets before, this is the first-ever observation of an exoplanet actively carving a gap within a disk -- the earliest direct glimpse of planetary sculpting in action.

https://apod.nasa.gov/apod/ap250827.html ( August 27, 2025)

Sometimes even the sky surprises you. To see more stars and faint nebulosity in the Pleiades star cluster (M45), long exposures are made. Many times, less interesting items appear on the exposures that were not intended -- but later edited out. These include stuck pixels, cosmic ray hits, frames with bright clouds or Earth's Moon, airplane trails, lens flares, faint satellite trails, and even insect trails. Sometimes, though, something really interesting is caught by chance. That was just the case a few weeks ago in al-Ula, Saudi Arabia when a bright meteor streaked across during an hour-long exposure of the Pleiades. Along with the famous bright blue stars, less famous and less bright blue stars, and blue-reflecting dust surrounding the star cluster, the fast rock fragment created a distinctive green glow, likely due to vaporized metals.

https://apod.nasa.gov/apod/ap250825.html ( August 25, 2025)

At the core of the Crab Nebula lies a city-sized, magnetized neutron star spinning 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 twelve light-years across, the spectacular picture frames the glowing gas, cavities and swirling filaments near the Crab Nebula's center. The featured picture combines visible light from the Hubble Space Telescope in purple, X-ray light from the Chandra X-ray Observatory in blue, and infrared light from the Spitzer Space Telescope in red. Like a cosmic dynamo, the Crab pulsar powers the emission from the nebula, driving a shock wave through surrounding material and accelerating the spiraling electrons. With more mass than the Sun and the density of an atomic nucleus,the spinning pulsar is the collapsed core of a massive star that exploded. The outer parts of the Crab Nebula are the expanding remnants of the star's component gases. The supernova explosion was witnessed on planet Earth in the year 1054.

https://apod.nasa.gov/apod/ap250824.html ( August 24, 2025)

How big is planet Earth's Moon? Compared to other moons of the Solar System, it's number 5 on the largest to smallest ranked list, following Jupiter's moon Ganymede, Saturn's moon Titan, and Jovian moons Callisto and Io. Continuing the list, the Moon comes before Jupiter's Europa and Neptune's Triton. It's also larger than dwarf planets Pluto and Eris. With a diameter of 3,475 kilometers the Moon is about 1/4 the size of Earth though, and that does make it the largest moon when compared to the size of its parent Solar System planet. Of course in this serene, twilight sea and skyscape, August's rising Full Moon still appears small enough to be caught in the nets of an ancient fishing rig. The telephoto snapshot was taken along the Italian Costa dei Trabocchi, on the Adriatic Sea.

https://apod.nasa.gov/apod/ap250823.html ( August 23, 2025)

This colorful telescopic view towards the musical northern constellation Lyra reveals the faint outer halos and brighter central ring-shaped region of M57, popularly known as the Ring Nebula. To modern astronomers M57 is a well-known planetary nebula. With a central ring about one light-year across, M57 is definitely not a planet though, but the gaseous shroud of one of the Milky Way's dying sun-like stars. Roughly the same apparent size as M57, the fainter and more often overlooked barred spiral galaxy at the left is IC 1296. In fact, over 100 years ago IC 1296 would have been known as a spiral nebula. By chance the pair are in the same field of view, and while they appear to have similar sizes they are actually very far apart. At a distance of a mere 2,000 light-years M57 is well within our own Milky Way galaxy. Extragalactic IC 1296 (aka PGC62532) is more like 200,000,000 light-years distant. That's about 100,000 times farther away than M57 but since they appear roughly similar in size, former spiral nebula IC 1296 must also be about 100,000 times larger than planetary nebula M57. Look closely at the sharp 21st century astroimage to spot even more distant background galaxies scattered through the frame.

https://apod.nasa.gov/apod/ap250822.html ( August 22, 2025)

In this predawn skyscape recorded during the early morning hours of August 13, mostly Perseid meteors are raining down on planet Earth. You can easily identify the Perseid meteor streaks. They're the ones with trails that seem to converge on the annual meteor shower's radiant, a spot in the heroic constellation Perseus, located off the top of the frame. That's the direction in Earth's sky that looks along the orbit of this meteor shower's parent, periodic Comet Swift-Tuttle. Of course the scene is a composite, a combination of about 500 digital exposures to capture meteors registered with a single base frame exposure. But all exposures were taken during a period of around 2.5 hours from a wind farm near Mönchhof, Burgenland, Austria. Red lights on the individual wind turbine towers dot the foreground. In their spectacular close conjunction, bright planets Jupiter and Venus are poised above the eastern horizon.

https://apod.nasa.gov/apod/ap250821.html ( August 21, 2025)

What are those curved arcs in the sky? Meteors -- specifically, meteors from this year's Perseid meteor shower. Over the past few weeks, after the sky darkened, many images of Perseid meteors were captured separately and merged into a single frame, taken earlier. 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 vertically through the featured image's center. The limestone arch in the foreground in Dorset, England is known as Durdle Door, a name thought to survive from a thousand years ago.

https://apod.nasa.gov/apod/ap250820.html ( August 20, 2025)

Over 500,000 light years across, NGC 6872 (bottom left) is a truly enormous barred spiral galaxy. At least 5 times the size of our own large Milky Way, NGC 6872 is the largest known spiral galaxy. About 200 million light-years distant toward the southern constellation Pavo, the Peacock, the appearance of this giant galaxy's stretched out spiral arms suggest the wings of a giant bird. So its popular moniker is the Condor galaxy. Lined with massive young, bluish star clusters and star-forming regions, the extended and distorted spiral arms are due to NGC 6872's past gravitational interactions with the nearby smaller galaxy IC 4970, visible here below the giant spiral galaxy's core. Other members of the southern Pavo galaxy group are scattered through this magnificent galaxy group portrait, with the dominant giant elliptical galaxy, NGC 6876, above and right of the soaring Condor galaxy.

https://apod.nasa.gov/apod/ap250819.html ( August 19, 2025)

This galaxy is not only pretty -- it's useful. A gorgeous spiral some 100 million light-years distant, NGC 1309 lies on the banks of the constellation of the River (Eridanus). NGC 1309 spans about 30,000 light-years, making it about one third the size of our larger Milky Way galaxy. Bluish clusters of young stars and dust lanes are seen to trace out NGC 1309's spiral arms as they wind around an older yellowish star population at its core. Not just another pretty face-on spiral galaxy, observations of NGC 1309's two recent supernovas and multiple Cepheid variable stars contribute to the calibration of the expansion of the Universe. Still, after you get over this beautiful galaxy's grand design, check out the array of more distant background galaxies also recorded in this sharp image from the Hubble Space Telescope.

https://apod.nasa.gov/apod/ap250818.html ( August 18, 2025)

What kind of clouds are these? Although their cause is presently unknown, such unusual atmospheric structures, as menacing as they might seem, do not appear to be harbingers of meteorological doom. Formally recognized as a distinct cloud type only last year, asperitas clouds can be stunning in appearance, unusual in occurrence, and are relatively unstudied. Whereas most low cloud decks are flat bottomed, asperitas clouds appear to have significant vertical structure underneath. Speculation therefore holds that asperitas clouds might be related to lenticular clouds that form near mountains, or mammatus clouds associated with thunderstorms, or perhaps a foehn -- a type of dry downward wind that flows off mountains. Clouds from such a wind called the Canterbury arch stream toward the east coast of New Zealand's South Island. The featured image, taken above Hanmer Springs in Canterbury, New Zealand in 2005, shows great detail partly because sunlight illuminates the undulating clouds from the side.

https://apod.nasa.gov/apod/ap250817.html ( August 17, 2025)

The camera battery died about 2am local time on August 12, while shooting in the bright moonlit skies from a garden in Chastre, Brabant Wallon, Belgium, planet Earth. But not before it captured the frames used to compose this cool animated gif of a brilliant Perseid meteor and a lingering visible trail known as a persistent train. The Perseid meteor, a fast moving speck of dust from the tail of large periodic Comet Swift-Tuttle, was heated to incandescence by ram pressure and vaporized as it flashed through the upper atmosphere at 60 kilometers per second. Compared to the brief flash of the meteor, its wraith-like trail really is persistent. A characteristic of bright meteors, a smoke-like persistent train can often be followed for many minutes wafting in the winds at altitudes of 60 to 90 kilometers.

https://apod.nasa.gov/apod/ap250816.html ( August 16, 2025)

In the predawn sky on August 13, two planets were close. And despite the glare of a waning gibbous Moon, bright Jupiter and even brighter Venus were hard to miss. Their brilliant close conjunction is posing above the eastern horizon in this early morning skyscape. The scene was captured in a single exposure from a site near Gansu, China, with light from both planets reflected in the still waters of a local pond. Also seen against the moonlight were flashes from the annual Perseid Meteor Shower, known for its bright, fast meteors. Near the much anticipated peak of activity, the shower meteors briefly combined with the two planets for a celestial spectacle even in moonlit skies.

https://apod.nasa.gov/apod/ap250815.html ( August 15, 2025)

In 1716, English astronomer Edmond Halley noted, "This is but a little Patch, but it shews itself to the naked Eye, when the Sky is serene and the Moon absent." Of course, M13 is now less modestly recognized as the Great Globular Cluster in Hercules, one of the brightest globular star clusters in the northern sky. Sharp telescopic views like this one reveal the spectacular cluster's hundreds of thousands of stars. At a distance of 25,000 light-years, the cluster stars crowd into a region 150 light-years in diameter. Approaching the cluster core, upwards of 100 stars could be contained in a cube just 3 light-years on a side. For comparison with our neighborhood of the Milky Way, the closest star to the Sun is over 4 light-years away. Early telescopic observers of the great globular cluster also noted a curious convergence of three dark lanes with a spacing of about 120 degrees, seen here just below the cluster center. Known as the propeller in M13, the shape is likely a chance optical effect of the distribution of stars viewed from our perspective against the dense cluster core.

https://apod.nasa.gov/apod/ap250814.html ( August 14, 2025)

What lies in the heart of Orion? Trapezium: four bright stars, that can be found near the center of this sharp cosmic portrait. Gathered within a region about 1.5 light-years in radius, these stars dominate the core of the dense Orion Nebula Star Cluster. Ultraviolet ionizing radiation from the Trapezium stars, mostly from the brightest star Theta-1 Orionis C powers the complex star forming region's entire visible glow. About three million years old, the Orion Nebula Cluster was even more compact in its younger years and a dynamical study indicates that runaway stellar collisions at an earlier age may have formed a black hole with more than 100 times the mass of the Sun. The presence of a black hole within the cluster could explain the observed high velocities of the Trapezium stars. The Orion Nebula's distance of some 1,500 light-years make it one of the closest candidate black holes to Earth.

https://apod.nasa.gov/apod/ap250813.html ( August 13, 2025)

Where are all of these meteors coming from? In terms of direction on the sky, the pointed answer is the constellation of Perseus. That is why the meteor shower that peaks tonight is known as the Perseids -- the meteors all appear to come from a radiant toward Perseus. In terms of parent body, though, the sand-sized debris that makes up the Perseids meteors come from Comet Swift-Tuttle. The comet follows a well-defined orbit around our Sun, and the part of the orbit that approaches Earth is superposed in front of Perseus. Therefore, when Earth crosses this orbit, the radiant point of falling debris appears in Perseus. Featured here, a composite image taken over six nights and containing over 100 meteors from 2024 August Perseids meteor shower shows many bright meteors that streaked over the Bieszczady Mountains in Poland. This year's Perseids, usually one of the best meteor showers of the year, will compete with a bright moon that will rise, for many locations, soon after sunset.

https://apod.nasa.gov/apod/ap250812.html ( August 12, 2025)

What's that strange light down the road? Dust orbiting the Sun. At certain times of the year, a band of sun-reflecting dust from the inner Solar System appears prominently just after sunset -- or just before sunrise -- and is called zodiacal light. Although the origin of this dust is still being researched, a leading hypothesis holds that zodiacal dust originates mostly from faint Jupiter-family comets and slowly spirals into the Sun. Recent analysis of dust emitted by Comet 67P, visited by ESA's robotic Rosetta spacecraft, bolsters this hypothesis. Pictured when climbing a road up to Teide National Park in the Canary Islands of Spain, a bright triangle of zodiacal light appeared in the distance soon after sunset. Captured on June 21, 2019, the scene includes bright Regulus, the alpha star of the constellation Leo, standing above center toward the left. The Beehive Star Cluster (M44) can be spotted below center, closer to the horizon and also immersed in the zodiacal glow.

https://apod.nasa.gov/apod/ap250810.html ( August 10, 2025)

Discovered on July 1 with the NASA-funded ATLAS (Asteroid Terrestrial-impact Last Alert System) survey telescope in Rio Hurtado, Chile, 3I/ATLAS is so designated as the third known interstellar object to pass through our Solar System. It follows 1I/ʻOumuamua in 2017 and the comet 2I/Borisov in 2019. Also known as C/2025 N1, 3I/ATLAS is a comet. A teardrop-shaped cloud of dust, ejected from its icy nucleus warmed by increasing sunlight, is seen in this sharp image from the Hubble Space Telescope captured on July 21. Background stars are streaked in the exposure as Hubble tracked the fastest comet ever recorded on its journey toward the inner solar system. An analysis of the Hubble image indicates the solid nucleus, hidden from direct view, is likely less that 5.6 kilometers in diameter. This comet's interstellar origin is clear from its orbit, determined to be an eccentric, highly hyperbolic orbit that does not loop back around the Sun and will return 3I/ATLAS to interstellar space. Not a threat to planet Earth, the inbound interstellar interloper is now within the Jupiter's orbital distance of the Sun, while its closest approach to the Sun will bring it just inside the orbital distance of Mars.

https://apod.nasa.gov/apod/ap250809.html ( August 09, 2025)

One of the all-time historic skyscapes occured in July 1054, when the Crab Supernova blazed into the dawn sky. Chinese court astrologers first saw the Guest Star on the morning of 4 July 1054 next to the star Tianguan (now cataloged as Zeta Tauri). The supernova peaked in late July 1054 a bit brighter than Venus, and was visible in the daytime for 23 days. The Guest Star was so bright that every culture around the world inevitably discovered the supernova independently, although only nine reports survive, including those from China, Japan, and Constantinople. This iPhone picture is from Signal Hill near Tucson on the morning of 26 July 2025, faithfully re-creates the year 1054 Dawn of the Crab, showing the sky as seen by Hohokam peoples. The planet Venus, as a stand-in for the supernova, is close to the position of what is now the Crab Nebula supernova remnant. Step outside on a summer dawn with bright Venus, and ask yourself "What would you have thought in ancient times when suddenly seeing the Dawn of the Crab?"

https://apod.nasa.gov/apod/ap250808.html ( August 08, 2025)

This stunning starfield spans about three full moons (1.5 degrees) across the heroic northern constellation of Perseus. It holds the famous pair of open star clusters, h and Chi Persei. Also cataloged as NGC 869 (right) and NGC 884, both clusters are about 7,000 light-years away and contain stars much younger and hotter than the Sun. Separated by only a few hundred light-years, the clusters are both 13 million years young based on the ages of their individual stars, evidence that both clusters were likely a product of the same star-forming region. Always a rewarding sight in binoculars or small telescopes, the Double Cluster is even visible to the unaided eye from dark locations.

https://apod.nasa.gov/apod/ap250807.html ( August 07, 2025)

What's that green streak in front of the Andromeda galaxy? A meteor. While photographing the Andromeda galaxy in 2016, near the peak of the PerseidMeteorShower, a small pebble from deep space crossed right in front of our Milky Way Galaxy's far-distant companion. The small meteor took only a fraction of a second to pass through this 10-degree field. The meteor flared several times while braking violently upon entering Earth's atmosphere. The green color was created, at least in part, by the meteor's gas glowing as it vaporized. Although the exposure was timed to catch a Perseid meteor, the orientation of the imaged streak seems a better match to a meteor from the Southern Delta Aquariids, a meteor shower that peaked a few weeks earlier. Not coincidentally, the Perseid Meteor Shower peaks next week, although this year the meteors will have to outshine a sky brightened by a nearly full moon.

https://apod.nasa.gov/apod/ap250806.html ( August 06, 2025)

Why is this nebula so complex? The Webb Space Telescope has imaged a nebula in great detail that is thought to have emerged from a Sun-like star. NGC 6072 has been resolved into one of the more unusual and complex examples of planetary nebula. The featured image is in infrared light with the red color highlighting cool hydrogen gas. Study of previous images of NGC 6072 indicated several likely outflows and two disks inside the jumbled gas, while the new Webb image resolves new features likely including one disk's edge protruding on the central left. A leading origin hypothesis holds that the nebula's complexity is caused or enhanced by multiple outbursts from a star in a multi-star system near the center.

https://apod.nasa.gov/apod/ap250805.html ( August 05, 2025)

What are these gigantic blue arcs near the Andromeda Galaxy (M31)? Discovered in 2022 by amateur astronomers, the faint arcs -- dubbed SDSO 1 -- span nearly the same angular size as M31 itself. At first, their origin was a mystery: are they actually near the Andromeda Galaxy, or alternatively near to our Sun? Now, over 550 hours of combined exposure and a collaboration between amateur and professional astronomers has revealed strong evidence for their true nature: SDSO 1 is not intergalactic, but a new class of planetary nebula within our galaxy. Dubbed a Ghost Planetary Nebula (GPN), SDSO 1 is the first recognized member of a new subclass of faded planetary nebulas, along with seven others also recently identified. Shown in blue are extremely faint oxygen emission from the shock waves, while the surrounding red is a hydrogen-emitting trail that indicates the GPN's age.

https://apod.nasa.gov/apod/ap250804.html ( August 04, 2025)

In about a week the Perseid Meteor Shower will reach its maximum. Grains of icy rock will streak across the sky as they evaporate during entry into Earth's atmosphere. These grains were shed from Comet Swift-Tuttle. The Perseids result from the annual crossing of the Earth through Comet Swift-Tuttle's orbit, and are typically the most active meteor shower of the year. Although it is hard to predict the level of activity in any meteor shower, in a clear dark sky an observer might see a meteor a minute. This year's Perseids peak just a few days after full moon, and so some faint meteors will be lost to the lunar skyglow. Meteor showers in general are best seen from a relaxing position, away from lights. Featured here is a meteor caught exploding during the 2015 Perseids above Austria next to the central band of our Milky Way Galaxy.

https://apod.nasa.gov/apod/ap250803.html ( August 03, 2025)

Taken on July 29 and July 30, a registered and stacked series of exposures creates this dreamlike view of a northern summer night. Multiple firefly flashes streak across the foreground as the luminous Milky Way arcs above the horizon in the Sierra de Órganos national park of central Mexico, The collection of bright streaks aligned across the sky toward the upper left in the timelapse image are Delta Aquariid meteors. Currently active, the annual Delta Aquarid meteor shower shares August nights though, overlapping with the better-known Perseid meteor shower. This year that makes post-midnight, mostly moonless skies in early August very popular with late night skygazers. How can you tell a Delta Aquariid from a Perseid meteor? The streaks of Perseid meteors can be traced back to an apparent radiant in the constellation Perseus. Delta Aquariids appear to emerge from the more southerly constellation Aquarius, beyond the top left of this frame. Of course, the bioluminescent flashes of fireflies are common too on these northern summer nights. But how can you tell a firefly from a meteor? Just try to catch one.

https://apod.nasa.gov/apod/ap250802.html ( August 02, 2025)

A small, dark, nebula looks isolated near the center of this telescopic close-up. The wedge-shaped cosmic cloudlet lies within a relatively crowded region of space though. About 7,000 light-years distant and filled with glowing gas and an embedded cluster of young stars, the region is known as M16 or the Eagle Nebula. Hubble's iconic images of the Eagle Nebula include the famous star-forming Pillars of Creation, towering structures of interstellar gas and dust 4 to 5 light-years long. But this small dark nebula, known to some as a Bok globule, is a fraction of a light-year across. The Bok globule stands out in silhouette against the expansive background of M16's diffuse glow. Found scattered within emission nebulae and star clusters, Bok globules are small interstellar clouds of cold molecular gas and obscuring dust that also form stars within their dense, collapsing cores.

https://apod.nasa.gov/apod/ap250801.html ( August 01, 2025)

A long time ago in a galaxy 50 million light-years away, a star exploded. Light from that supernova was first detected by telescopes on planet Earth on July 14th though, and the extragalactic transient is now known to astronomers as supernova 2025rbs. Presently the brightest supernova in planet Earth's sky, 2025rbs is a Type Ia supernova, likely caused by the thermonuclear detonation of a white dwarf star that accreted material from a companion in a binary star system. Type Ia supernovae are used as standard candles to establish the distance scale of the universe. The host galaxy of 2025rbs is NGC 7331. Itself a bright spiral galaxy in the northern constellation Pegasus, NGC 7331 is often touted as an analog to our own Milky Way.

https://apod.nasa.gov/apod/ap250731.html ( July 31, 2025)

Our Sun frequently erupts in loops. Hot solar plasma jumps off the Sun's surface into prominences, with the most common type of prominence being a simple loop. The loop shape originates from the Sun's magnetic field, which is traced by spiraling electrons and protons. Many loops into the Sun's lower corona are large enough to envelop the Earth and are stable enough to last days. They commonly occur near active regions that also include dark sunspots. The featured panel shows four loops, each of which was captured near the Sun's edge during 2024 and 2025. The images were taken by a personal telescope in Mantova, Italy and in a very specific color of light emitted primarily by hydrogen. Some solar prominences suddenly break open and eject particles into the Solar System, setting up a space weather sequence that can affect the skies and wires of Earth.

https://apod.nasa.gov/apod/ap250730.html ( July 30, 2025)

Is the Helix Nebula looking at you? No, not in any biological sense, but it does look quite like an eye. The Helix Nebula is so named because it also appears that you are looking down the axis of a helix. In actuality, it is now understood to have a surprisingly complex geometry, including radial filaments and extended outer loops. The Helix Nebula (aka NGC 7293) is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The featured picture, taken in red, green, and blue but highlighted by light emitted primarily by hydrogen was created from 12 hours of exposure through a personal telescope located in Greece. A close-up of the inner edge of the Helix Nebula shows complex gas knots the origin of which are still being researched.

https://apod.nasa.gov/apod/ap250729.html ( July 29, 2025)

Have you ever watched a lightning storm in awe? You're not alone. Details of what causes lightning are still being researched, but it is known that inside some clouds, internal updrafts cause collisions between ice and snow that slowly separate charges between cloud tops and bottoms. The rapid electrical discharges that are lightning soon result. Lightning usually takes a jagged course, rapidly heating a thin column of air to about three times the surface temperature of the Sun. The resulting shock wave starts supersonically and decays into the loudsound known as thunder. On average, around the world, about 6,000 lightning bolts occur between clouds and the Earth every minute. Pictured in July 2019 in a two-image composite, lightning stems from communication antennas near the top of Volcán de Agua (Volcano of Water) in Guatemala.

https://apod.nasa.gov/apod/ap250727.html ( July 27, 2025)

Globular star cluster Omega Centauripacks about 10 million stars much older than the Sun into a volume some 150 light-years in diameter. Also known as NGC 5139, at a distance of 15,000 light-years it's the largest and brightest of 200 or so known globular clusters that roam the halo of our Milky Way galaxy. Though most star clusters consist of stars with the same age and composition, the enigmatic Omega Cen exhibits the presence of different stellar populations with a spread of ages and chemical abundances. In fact, Omega Cen may be the remnant core of a small galaxy merging with the Milky Way. With a yellowish hue, Omega Centauri's red giant stars are easy to pick out in this sharp telescopic view. A two-decade-long exploration of the dense star cluster with the Hubble Space Telescope has revealed evidence for a massive black hole near the center of Omega Centauri.

https://apod.nasa.gov/apod/ap250726.html ( July 26, 2025)

Meteors from the Kappa Cygnid meteor shower are captured in this time-lapse composite skyscape. The minor meteor shower, with a radiant not far from its eponymous star Kappa Cygni, peaks in mid-August, almost at the same time as the much better-known and better-observed Perseid meteor shower. But, seen to have a peak rate of only about 3 meteors per hour, Kappa Cygnids are vastly outnumbered by the more popular, prolific Perseid shower's meteors that emanate from the heroic constellation Perseus. To capture dozens of Kappa Cygnids, this long term astro-imaging project compiled meteors in exposures selected from over 51 August nights during the years 2012 through 2024. Most of the exposures with identified Kappa Cygnid meteors were made in August 2021, a high point of the shower's known 7-year activity cycle. All twelve years worth of Kappa Cygnids are registered against a base sea and night skyscape of the Milky Way above Elafonisi Beach, Crete, Greece, also recorded in August of 2021.

https://apod.nasa.gov/apod/ap250725.html ( July 25, 2025)

Every 15 years or so, Saturn's rings are tilted edge-on to our line of sight. As the bright, beautiful ring system grows narrower and fainter it becomes increasingly difficult to see for denizens of planet Earth. But it does provide the opportunity to watch transits of Saturn's moons and their dark shadows across the ringed gas giant's still bright disk. Of course Saturn's largest moon Titan is the easiest to spot in transit. In this telescopic snapshot from July 18, Titan itself is at the upper left, casting a round dark shadow on Saturn's banded cloudtops above the narrow rings. In fact Titan's transit season is in full swing now with shadow transits every 16 days corresponding to the moon's orbital period. Its final shadow transit will be on October 6, though Titan's pale disk will continue to cross in front of Saturn as seen from telescopes on planet Earth every 16 days through January 25, 2026.

https://apod.nasa.gov/apod/ap250724.html ( July 24, 2025)